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Background: The aim of this study was to evaluate the inter-fraction reproducibility and intra-fraction stability of breast radiotherapy using voluntary deep-inspiration breath hold (DIBH) and free breathing (FB) based on an optical surface imaging system (OSIS). Methods: Seventeen patients (510 breath-hold sessions) treated using a field-in-field (FiF) technique and twenty patients (600 breath-free sessions) treated with a volume-modulated arc therapy (VMAT) technique were included in this retrospective study. All the patients were positioned with the guidance of CBCT and OSIS, and also monitored with OSIS throughout the whole treatment session. Eight setup variations in three directions were extracted from the treatment reports of OSIS for all sessions and were subsequently manually introduced to treatment plans, resulting in a total of 296 perturbed plans. All perturbed plans were recalculated, and the dose volume histograms (DVH) for the target and organs at risk (OAR) were analyzed. Results: The OSIS and CBCT for both DIBH and FB treatments showed a good agreement of less than 0.30 cm in each direction. The intra-fraction respiratory motion data during DIBH were −0.06 ± 0.07 cm, 0.12 ± 0.15 cm, and 0.12 ± 0.12 cm in the lateral, longitudinal, and vertical directions, respectively; for FB, the respiratory motion data were −0.02 ± 0.12 cm, 0.08 ± 0.18 cm, and 0.14 ± 0.20 cm, respectively. For the target, DIBH plans were more sensitive to setup errors; the mean deviations in D95 for CTV were 39.78 Gy–40.17 Gy for DIBH and 38.46 Gy–40.52 Gy for FB, respectively. For the OARs, the mean deviations of V10, V20, and Dmean to the heart; V5, V20, and Dmean to the ipsilateral lung; and Dmean to the breast were lower for the FB plan compared with the DIBH plan. Conclusion: Based on OSIS, our results indicate that both DIBH and FB can provide good reproducibility in the inter-fractions and stability in the intra-fractions. When the patient respiratory motion is large, the FB technology has greater possibility for the undercoverage of the target volume, while DIBH technology is more likely to result in increases in dose to OARs (the lung, heart, and contralateral breast). [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to analyze and estimate planning risk volume (PRV) margin for heart in deep inspiration breath hold (DIBH)-based left breast radiotherapy. Materials and Methods: Fifty left-sided cancer breast cases treated with volumetric modulated arc radiotherapy were included in this retrospective study. Treatment plans were created using the Eclipse treatment planning system from Varian Medical System. The treatment was delivered on TrueBeam linear accelerator (Varian). Onboard cone-beam computed tomography (CBCT) images were generated and image registration between the planning computed tomography images and the CBCT images was performed before treatment delivery. The registration provided the shifts (errors) values in 6° of freedom, namely three translational and three rotational. From the shift values, the systematic and random errors were estimated which were used to estimate PRV margin for the heart after incorporating the rotational errors with the translational errors. Results: The systematic error values after incorporating rotational errors with translational errors were 0.13 cm (lateral) and 0.11 cm (cranio caudal [CC] and anterioposterior each), and the random error values were 0.16 cm (lateral) and 0.13 cm (CC and anterioposterior each). Based on these values, the PRV margins for the heart in all three directions were 0.24 cm (lateral), 0.20 cm (CC), and 0.19 cm (anterioposterior). Conclusion: As per our institutional practice, the 2 mm value for PRV margin for the heart in all the three directions would suffice for appropriate sparing of the heart during DIBH-based radiation therapy.

Abstract Background The aim of this study was to evaluate the inter-fraction reproducibility and intra-fraction stability of breast radiotherapy using voluntary deep-inspiration breath hold (DIBH) and free breathing (FB) based on an optical surface imaging system (OSIS). Methods Seventeen patients (510 breath-hold sessions) treated using a field-in-field (FiF) technique and twenty patients (600 breath-free sessions) treated with a volume-modulated arc therapy (VMAT) technique were included in this retrospective study. All the patients were positioned with the guidance of CBCT and OSIS, and also monitored with OSIS throughout the whole treatment session. Eight setup variations in three directions were extracted from the treatment reports of OSIS for all sessions and were subsequently manually introduced to treatment plans, resulting in a total of 296 perturbed plans. All perturbed plans were recalculated, and the dose volume histograms (DVH) for the target and organs at risk (OAR) were analyzed. Results The OSIS and CBCT for both DIBH and FB treatments showed a good agreement of less than 0.30 cm in each direction. The intra-fraction respiratory motion data during DIBH were −0.06 ± 0.07 cm, 0.12 ± 0.15 cm, and 0.12 ± 0.12 cm in the lateral, longitudinal, and vertical directions, respectively; for FB, the respiratory motion data were −0.02 ± 0.12 cm, 0.08 ± 0.18 cm, and 0.14 ± 0.20 cm, respectively. For the target, DIBH plans were more sensitive to setup errors; the mean deviations in D95 for CTV were 39.78 Gy–40.17 Gy for DIBH and 38.46 Gy–40.52 Gy for FB, respectively. For the OARs, the mean deviations of V10, V20, and Dmean to the heart; V5, V20, and Dmean to the ipsilateral lung; and Dmean to the breast were lower for the FB plan compared with the DIBH plan. Conclusion Based on OSIS, our results indicate that both DIBH and FB can provide good reproducibility in the inter-fractions and stability in the intra-fractions. When the patient respiratory motion is large, the FB technology has greater possibility for the undercoverage of the target volume, while DIBH technology is more likely to result in increases in dose to OARs (the lung, heart, and contralateral breast).

Deep inspiration breath-hold (DIBH) has proven effective in minimizing radiation exposure to organs at risk (OARs) in right-sided breast cancer patients requiring regional nodal irradiation (RNI). However, there has been no dosimetric evaluation comparing DIBH techniques to free-breathing (FB) conditions on the TrueBeam (TB) HD linear accelerator (LINAC). To address this gap and accommodate breast cancer patients requiring RNI on the TB HD LINAC, an innovative method involving a 90-degree rotation of the regional lymph nodes' field during treatment planning was devised. The study focused on a 39-year-old woman who underwent right breast-conserving radical surgery and subsequently required postoperative adjuvant radiotherapy. Both noncontrast FB and DIBH computed tomography (CT) scans were performed using a CT simulator. Due to limitations in MLC field length, a 90-degree rotation was employed for planning the regional lymph nodes' field on the TB LINAC. Patient positioning accuracy was ensured by aligning based on body surface under both FB and DIBH conditions, facilitated by an optical surface management system (OSMS). The target volume and OARs were meet the dose limit on the TB HD LINAC. Noteworthy reductions in radiation exposure to the right lung and liver were evident with DIBH. The mean dose reduction rate for the right lung was 11.9%, while the mean dose reduction rate for the liver was 68.9%. Parameters such as V5, V20, V30, and mean dose (Dmean) also demonstrated decreases with DIBH compared to FB. This case report underscores the potential of TB HD LINAC for formulating treatment approaches for breast cancer involving RNI. Furthermore, it emphasizes the effectiveness of DIBH radiotherapy in mitigating doses to OARs when implemented on the TB LINAC. [ABSTRACT FROM AUTHOR]

Abstract Objectives The study aims to emphasize the clinical importance of the Deep Inspiration Breath Hold (DIBH) technique by quantifying its dosimetric advantages over Free Breathing (FB) in reducing radiation exposure to the heart, liver, and lungs for right-sided breast cancer patients. This evidence supports its potential for routine clinical use to mitigate radiation-induced toxicity. Methods A systematic retrieval of controlled trials comparing DIBH and FB techniques in postoperative radiotherapy for right-sided breast cancer was conducted utilizing the PubMed, Embase, Cochrane Library, and Web of Science databases. The primary outcomes assessed included the doses of adjacent normal tissues (heart, liver, and lungs). Summary standardized mean differences (SMD) along with 95% confidence intervals (CI) were computed, respectively. StataMP 17 software was selected to perform data analysis. Results The study encompassed an analysis of 313 patients derived from seven online studies, comprising 168 individuals in the DIBH group and 269 individuals in the FB group. The findings indicated that the DIBH group received significantly lower irradiation doses to the heart, liver, and lungs in comparison to the FB group, with statistical significance (heart dose: SMD = -0.63, 95% CI -0.85 to -0.41, P

Abstract Introduction The currently accepted best practice radiation treatment for left breast cancer patients is Deep Inspiration Breath Hold (DIBH) where patients hold a deep breath to reduce late cardiac and pulmonary effects from treatment. DIBH can be challenging and induce or exacerbate anxiety in patients due to the perceived pressure to reduce radiation treatment side effects. This study explored the experiences of patients treated with Deep Inspiration Breath Hold Radiation Therapy (DIBH‐RT) to improve patient‐centred care and inform the design of multimedia educational tools for future patients undergoing DIBH. Methods This descriptive qualitative study was underpinned by a social constructivist approach to create new educational and patient care approaches based on previous patients' experiences. Semi‐structured interviews were conducted with patients who had completed DIBH‐RT for breast cancer. Data was analysed with reflexive thematical analysis. Results Twenty‐two patients were interviewed with five key themes identified: (1) informational needs, (2) care needs, (3) autonomy, (4) DIBH performance influencers and (5) other centredness. Recommendations were derived from these themes to improve future treatments of DIBH patients. These recommendations revolved around improvements to education, patient‐centred care and strategies to improve self‐efficacy with breath holding. Conclusion Patients offer a wealth of knowledge regarding their lived experiences with treatment which can enhance future patients' experiences if incorporated into their education and care. Eliciting patients' views of their DIBH‐RT treatment highlighted the need to improve patient self‐efficacy with DIBH through familiarity with their planned treatment from new multimedia education, and foster patient care to enhance their experience.

Objectives: The study aims to emphasize the clinical importance of the Deep Inspiration Breath Hold (DIBH) technique by quantifying its dosimetric advantages over Free Breathing (FB) in reducing radiation exposure to the heart, liver, and lungs for right-sided breast cancer patients. This evidence supports its potential for routine clinical use to mitigate radiation-induced toxicity. Methods: A systematic retrieval of controlled trials comparing DIBH and FB techniques in postoperative radiotherapy for right-sided breast cancer was conducted utilizing the PubMed, Embase, Cochrane Library, and Web of Science databases. The primary outcomes assessed included the doses of adjacent normal tissues (heart, liver, and lungs). Summary standardized mean differences (SMD) along with 95% confidence intervals (CI) were computed, respectively. StataMP 17 software was selected to perform data analysis. Results: The study encompassed an analysis of 313 patients derived from seven online studies, comprising 168 individuals in the DIBH group and 269 individuals in the FB group. The findings indicated that the DIBH group received significantly lower irradiation doses to the heart, liver, and lungs in comparison to the FB group, with statistical significance (heart dose: SMD = -0.63, 95% CI -0.85 to -0.41, P < 0.05; liver dose: SMD = -1.15, 95% CI -1.91 to -0.38, P < 0.05; lung dose: SMD = -0.79, 95% CI -1.23 to -0.35, P < 0.05). Conclusion: This meta-analysis indicated that the application of DIBH during postoperative radiotherapy for right-sided breast cancer markedly decreases radiation exposure to the heart, liver, and lungs, while maintaining consistent tumor dose coverage. Clinical trial number: Not applicable. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to analyze and estimate planning risk volume (PRV) margin for heart in deep inspiration breath hold (DIBH)-based left breast radiotherapy. Materials and Methods: Fifty left-sided cancer breast cases treated with volumetric modulated arc radiotherapy were included in this retrospective study. Treatment plans were created using the Eclipse treatment planning system from Varian Medical System. The treatment was delivered on TrueBeam linear accelerator (Varian). Onboard cone-beam computed tomography (CBCT) images were generated and image registration between the planning computed tomography images and the CBCT images was performed before treatment delivery. The registration provided the shifts (errors) values in 6° of freedom, namely three translational and three rotational. From the shift values, the systematic and random errors were estimated which were used to estimate PRV margin for the heart after incorporating the rotational errors with the translational errors. Results: The systematic error values after incorporating rotational errors with translational errors were 0.13 cm (lateral) and 0.11 cm (cranio caudal [CC] and anterioposterior each), and the random error values were 0.16 cm (lateral) and 0.13 cm (CC and anterioposterior each). Based on these values, the PRV margins for the heart in all three directions were 0.24 cm (lateral), 0.20 cm (CC), and 0.19 cm (anterioposterior). Conclusion: As per our institutional practice, the 2 mm value for PRV margin for the heart in all the three directions would suffice for appropriate sparing of the heart during DIBH-based radiation therapy. [ABSTRACT FROM AUTHOR]

Introduction: The currently accepted best practice radiation treatment for left breast cancer patients is Deep Inspiration Breath Hold (DIBH) where patients hold a deep breath to reduce late cardiac and pulmonary effects from treatment. DIBH can be challenging and induce or exacerbate anxiety in patients due to the perceived pressure to reduce radiation treatment side effects. This study explored the experiences of patients treated with Deep Inspiration Breath Hold Radiation Therapy (DIBH‐RT) to improve patient‐centred care and inform the design of multimedia educational tools for future patients undergoing DIBH. Methods: This descriptive qualitative study was underpinned by a social constructivist approach to create new educational and patient care approaches based on previous patients' experiences. Semi‐structured interviews were conducted with patients who had completed DIBH‐RT for breast cancer. Data was analysed with reflexive thematical analysis. Results: Twenty‐two patients were interviewed with five key themes identified: (1) informational needs, (2) care needs, (3) autonomy, (4) DIBH performance influencers and (5) other centredness. Recommendations were derived from these themes to improve future treatments of DIBH patients. These recommendations revolved around improvements to education, patient‐centred care and strategies to improve self‐efficacy with breath holding. Conclusion: Patients offer a wealth of knowledge regarding their lived experiences with treatment which can enhance future patients' experiences if incorporated into their education and care. Eliciting patients' views of their DIBH‐RT treatment highlighted the need to improve patient self‐efficacy with DIBH through familiarity with their planned treatment from new multimedia education, and foster patient care to enhance their experience. [ABSTRACT FROM AUTHOR]

Background: Daily image-guided radiotherapy (IGRT) and deep inspiration breath hold (DIBH) technique are recommended for locoregional RT of breast cancer. The optimal workflow for a combination of surface-guided RT (SGRT) with DIBH technique is of current clinical interest. Materials and methods: The setup accuracy at three hospitals was evaluated using different SGRT workflows. A total of 150 patients (2269 image pairs) were analyzed in three groups: patient setup with the AlignRT® SGRT system in Tampere (Site 1, n = 50), the Catalyst™ SGRT system in Turku (Site 2, n = 50) and the Catalyst™ SGRT system in Jönköping (Site 3, n = 50). Each site used their routine workflow with SGRT-based setup and IGRT positioning. Residual errors of the bony chest wall, thoracic vertebra (Th 1) and humeral head were evaluated using IGRT images. Results: Systematic residual errors in the cranio-caudal (CC) direction and in pitch were generally larger at Site 2 than those at Sites 1 and 3 (p = 0.01-0.7). With daily IGRT, only a small difference (p = 0.01-0.9) was observed in residual random errors of bony structures in other directions between sites. Conclusion: The introduction of SGRT and the use of daily IGRT lead to small residual errors when combining the best work- flow practices from different hospitals. Our multicenter evaluation led to improved workflow by tightening the SGRT tolerances on Site 2 and fixation modification. Because of mainly small random errors, systematic posture errors in the images need to be corrected after posture correction with new setup surfaces. We recommend tight SGRT tolerances, good fixation and correction of systematic errors. [ABSTRACT FROM AUTHOR]

The clinical use of surface imaging has increased dramatically, with demonstrated utility for initial patient positioning, real-time motion monitoring, and beam gating in a variety of anatomical sites. The Therapy Physics Subcommittee and the Imaging for Treatment Verification Working Group of the American Association of Physicists in Medicine commissioned Task Group 302 to review the current clinical uses of surface imaging and emerging clinical applications. The specific charge of this task group was to provide technical guidelines for clinical indications of use for general positioning, breast deep-inspiration breath hold treatment, and frameless stereotactic radiosurgery. Additionally, the task group was charged with providing commissioning and on-going quality assurance (QA) requirements for surface-guided radiation therapy (SGRT) as part of a comprehensive QA program including risk assessment. Workflow considerations for other anatomic sites and for computed tomography simulation, including motion management, are also discussed. Finally, developing clinical applications, such as stereotactic body radiotherapy (SBRT) or proton radiotherapy, are presented. The recommendations made in this report, which are summarized at the end of the report, are applicable to all video-based SGRT systems available at the time of writing.

Background: The objective was to compare dosimetry in left-sided breast cancer (LSBC) patients receiving deep inspiration breath hold (DIBH) radiotherapy (RT) with free-breathing (FB) treatment plans. Materials and methods: Voluntary DIBH with a spirometer-based video-assisted system and CT-simulation were performed under FB and DIBH conditions on 40 LSBC patients, segmented according Duane's atlas. IMRT plans kept the same dosimetric goals on FB and DIBH conditions. Target, lungs and heart volumes were measured. Planning target volume (PTV) dose distribution, organs at risk (OARs) dose/volume parameters, including cardiac substructures, were calculated. Results: Lungs and left-lung volumes increased in DIBH conditions (ΔV = 1637.8 ml ± 555.3 and 783.5 ml ± 286.4, respectively). Heart volume slightly decreased in apnea (p = 0.04), but target volumes, CTV and PTV were similar in FB or DIBH plans. PTV dose coverage was similar irrespective of respiratory conditions (median D50% = 41.1 Gy vs 41.0 Gy, p = 0.665; V95% = 96.9% vs. 97%). Mean dose for the whole heart (MHD), left ventricle (LV), and LV segments were significantly reduced in DIBH plans. V20 values for heart subvolumes were significantly different only for those that received considerable doses (apical and anterior). DIBH plans provided significantly smaller doses (Dmax, D2%, and V20) to the LAD artery. Conclusion: Important dosimetric improvements can be achieved with DIBH technique for LSBC patients, reducing the dose to the LAD artery and heart, particularly to the segments closer to the chest wall. Apical/anterior LV segments, should be considered as separate organ at risk in breast RT. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the impact of deep inspiration breath hold (DIBH) on the positioning of thoracic structures and provide treatment planning recommendations for internal mammary chain (IMC) irradiation in breast cancer patients. Thirty-two breast cancer patients from our database underwent both DIBH and free breathing (FB) treatment planning. Contouring of the axillary lymph node clinical target volumes (CTVs: level I, II, III, IV, and IMC according to ESTRO), the internal mammary artery (IMA), the heart, and the left anterior descending artery (LAD) was performed. The following were then analyzed: the distance between the IMA and the heart, the craniocaudal distance in which IMC-CTV and heart coexist, the craniocaudal distance between the lower end of the of level III and IV and the upper end of the heart. Several significant geometric differences were observed between DIBH and FB that explain the efficacy of the DIBH for regional nodal irradiation. In >80% of patients the cranial origin of the LAD lies below the lower edge of the IMC-CTV in DIBH. In addition the slices in which the heart/LAD and IMC-CTV coexist decrease during DIBH. The IMA-heart distance is significantly larger in DIBH. Also the craniocaudal distance between the lower border of the CTV level III and IV and the upper border of the heart is larger in DIBH. The observed mechanisms during DIBH contribute significantly to the dose reduction in regional nodal irradiation. To further enhance the benefits of DIBH for the irradiation of the IMC-CTV, it is recommended to implement steep dose gradients in the caudal plane. [ABSTRACT FROM AUTHOR]

Background: We aim to present our linear accelerator-based workflow for pancreatic stereotactic ablative radiotherapy (SABR) in order to address the following issues: intrafractional organ motion management, Cone Beam CT (CBCT) image quality, residual errors with dosimetric consequences, treatment time, and clinical results.Methods: Between 2016 and 2021, 14 patients with locally advanced pancreatic cancer were treated with induction chemotherapy and SABR using volumetric modulated arc therapy (VMAT). Internal target volume (ITV) concept (5), phase-gated (4), or breath hold (5) techniques were used. Treatment was verified by CBCT before and after irradiation, while tumor motion was monitored and controlled by kV triggered imaging and beam hold using peritumoral surgical clips. Beam interruptions and treatment time were recorded. The CBCT image quality was scored and supplemented by an agreement analysis (Krippendorff’s-α) of breath-hold CBCT images to determine the position of OARs relative to the planning risk volumes (PRV). Residual errors and their dosimetry impact were also calculated. Progression free (PFS) and overall survival (OS) were assessed by the Kaplan-Meier analysis with acute and late toxicity reporting (CTCAEv4).Results: On average, beams were interrupted once (range: 0–3) per treatment session on triggered imaging. The total median treatment time was 16.7 ± 10.8 min, significantly less for breath-hold vs. phase-gated sessions (18.8 ± 6.2 vs. 26.5 ± 13.4, p < 0.001). The best image quality was achieved by breath hold CBCT. The Krippendorff’s-α test showed a strong agreement among five radiation therapists (mean K-α value: 0.8 (97.5%). The mean residual errors were

Purpose To examine whether the use of surface-guided radiation therapy (SGRT) improved accuracy of patient setup determined by the quantity of images required for image-guided radiation therapy (IGRT). Methods This study used a quantitative research design to collect data after IGRT at a radiation therapy treatment center via randomized sampling. Patients undergoing IGRT were categorized into 2 treatment groups for this study: IGRT with SGRT and IGRT without SGRT. Radiation therapy fractions (N = 263) were analyzed according to treatment site, use of SGRT, use of cone-beam computed tomography (CBCT), total quantity of CBCT images, use of 2-D imaging (megavoltage [MV] or kilovoltage [kV]), and total quantity of 2-D images (MV or kV). Results When SGRT was used for patient setups, 100% of fractions to the lung, 100% to the esophagus, 93.8% to the abdomen, 100% to the chest wall, and 82.6% to the breast required 1 image to verify patient setup for IGRT. When SGRT was not used for patient setup, 100% of treatments (ie, fractions) to the head and neck, 7.7% to the brain, 50.0% to the extremity, 9.1% to gynecological sites, and 0% to the rectum, pelvis and prostate required 2 or more images to verify patient setup for IGRT. Discussion Concerns about increased exposure to ionizing radiation through repeat imaging during IGRT were explored in this study to determine if the use of SGRT might correlate with decreased dependency on traditional IGRT methods. IGRT is a standardized requirement for sufficient visual verification of anatomic positioning before initiating radiation therapy. SGRT is preferred for breast and chest wall setups to eliminate the need for more than 1 CBCT or 2-D image for positioning verification. To decrease repeat radiation exposure of healthy tissue surrounding the target volume from IGRT, alternative methods to ensure proper patient alignment, such as SGRT, should be explored further. Conclusion The use of SGRT for patient setup is beneficial in reducing dependence on IGRT, particularly in reducing the quantity of images required to verify adequate patient positioning for the initiation of radiation therapy. [ABSTRACT FROM AUTHOR]

ExacTrac Dynamic (ETD) provides a Deep Inspiration Breath Hold (DIBH) workflow for breast patients. Stereoscopic x-ray imaging combined with optical and thermal mapping allows localisation against simulation imaging, alongside surface guided breath hold monitoring. This work aimed to determine appropriate imaging parameters, the optimal Hounsfield Unit (HU) threshold for patient contour generation and workflow evaluation via end-to-end (E2E) positioning using a custom breast DIBH phantom. After localisation via existing Image Guidance (IG), stereoscopic imaging was performed with a range of parameters to determine best agreement. Similarly, residual errors in prepositioning were minimised using a range of HU threshold contours. E2E positioning was completed for clinical workflows allowing residual isocentre position error measurement and existing IG comparison. Parameters of 60 kV and 25mAs were determined appropriate for patient imaging and HU thresholds between −600 HU and −200 HU enabled adequate prepositioning. The average and standard deviation in residual isocentre position error was 1.0 ± 0.9 mm, 0.4 ± 1.0 mm and 0.1 ± 0.5 mm in the lateral, longitudinal and vertical directions, respectively. Errors measured using existing IG were −0.6 ± 1.1 mm, 0.5 ± 0.7 mm and 0.2 ± 0.4 mm in the lateral, longitudinal and vertical directions, and 0.0 ± 1.0o, 0.5 ± 1.7o and −0.8 ± 1.8o for pitch roll and yaw. The use of bone weighted matching increased residual error, while simulated reduction of DIBH volume maintained isocentre positioning accuracy despite anatomical changes. This initial testing indicated suitability for clinical implementation during DIBH breast treatments. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate three techniques of irradiation of left-sided breast cancer patients, three-dimensional conformal radiotherapy (3D-CRT), hybrid Intensity-Modulated Radiotherapy (h-IMRT), and hybrid Volumetric-Modulated Arc Therapy (h-VMAT, h-ARC), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim was to estimate the projected relative risk of radiation-induced secondary cancers for hybrid techniques. Three treatment plans were prepared in 3D-CRT, h-IMRT, and h-VMAT techniques for each of the 40 patients, who underwent CT simulation in deep inspiration breath-hold (DIBH). For hybrid techniques, plans were created by combining 3D-CRT and dynamic fields with an 80%/20% dose ratio for 3D-CRT and IMRT or VMAT. Cumulative dose–volume histograms were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], left and right lung [LL, RL], right breast [RB]). Projected risk ratios for secondary cancers were estimated relative to 3D-CRT using the organ equivalent dose (OED) concept for the Schneider's linear exponential, plateau, and full mechanistic dose–response model. All plans fulfilled the PTV criterium: V95%≥95%. Compared to 3D-CRT, both hybrid techniques showed significantly better target coverage (PTV: V95%>98%, p < 0.001), and the best conformality was achieved by h-ARC plans (CI: 1.18 ± 0.09, p < 0.001). Compared to 3D-CRT and h-ARC, h-IMRT increased the average sum of monitor units (MU) over 129.9% (p < 0.001). H-ARC increased the mean dose of contralateral organs and the LL V5Gy parameter (p < 0.001). Both hybrid techniques significantly reduced the Dmax of the heart by 5 Gy. Compared to h-IMRT, h-ARC increased secondary cancer projected relative risk ratios for LL, RL, and RB by 18, 152, and 81%, respectively. The results confirmed that both hybrid techniques provide better target quality and OARs sparing than 3D-CRT. Hybrid VMAT delivers less MU compared to hybrid IMRT but may increase the risk of radiation-induced secondary malignancies. [ABSTRACT FROM AUTHOR]

Abstract Background Deep inspiration breath hold (DIBH) reduces radiotherapy cardiac dose for left-sided breast cancer patients. The primary aim of the BRAVEHeart (Breast Radiotherapy Audio Visual Enhancement for sparing the Heart) trial is to assess the accuracy and usability of a novel device, Breathe Well, for DIBH guidance for left-sided breast cancer patients. Breathe Well will be compared to an adapted widely available monitoring system, the Real-time Position Management system (RPM). Methods BRAVEHeart is a single institution prospective randomised trial of two DIBH devices. BRAVEHeart will assess the DIBH accuracy for Breathe Well and RPM during left-sided breast cancer radiotherapy. After informed consent has been obtained, 40 patients will be randomised into two equal groups, the experimental arm (Breathe Well) and the control arm (RPM with in-house modification of an added patient screen). The primary hypothesis of BRAVEHeart is that the accuracy of Breathe Well in maintaining the position of the chest during DIBH is superior to the RPM system. Accuracy will be measured by comparing chest wall motion extracted from images acquired of the treatment field during breast radiotherapy for patients treated using the Breathe Well system and those using the RPM system. Discussion The Breathe Well device uses a depth camera to monitor the chest surface while the RPM system monitors a block on the patient’s abdomen. The hypothesis of this trial is that the chest surface is a better surrogate for the internal chest wall motion used as a measure of treatment accuracy. The Breathe Well device aims to deliver an easy-to-use implementation of surface monitoring. The findings from the study will help inform the technology choice for other centres performing DIBH. Trial registration ClinicalTrials.gov NCT02881203 . Registered on 26 August 2016.

Purpose: to predict eligibility for deep inspiration breath-hold (DIBH) radiotherapy (RT) treatment of patients with left breast cancer from analysis of respiratory signal, using Deep Bidirectional Long Short-Term Memory (BLSTM) recurrent neural networks. Methods: The respiratory traces from 36 patients who underwent DIBH RT were collected. The patients' RT treatment plans were generated for both DIBH and free-breathing (FB) modalities. The patients were divided into two classes (patient eligible or not), based on the decrease of maximum dose to the left anterior descending (LAD) artery achieved with DIBH, compared to that achieved with FB and ΔDL. Patients with ΔDL > median value of ΔDL within the patient cohort were assumed to be those selected for DIBH. A BLSTM-RNN was trained for classification of patients eligible for DIBH by analysis of their respiratory signals, as acquired during acquisition of the pre-treatment computed tomography (CT), for selecting the window for DIBH. The dataset was split into training (60%) and test groups (40%), and the hyper-parameters, including the number of hidden layers, the optimizer, the learning rate, and the number of epochs, were selected for optimising model performance. The BLSTM included 2 layers of 100 neural units, each followed by a dropout layer with 20% dropout, and was trained in 35 epochs using the Adam optimizer, with an initial learning rate of 0.0003. Results: The system achieved accuracy, specificity, and sensitivity of, F1 score and area under the receiving operating characteristic curve (AUC) of 71.4%, 66.7%, 80.1%, 72.4%, and 69.4% in the test dataset, respectively. Conclusions: The proposed BLSTM-RNN classified patients in the test set eligible for DIBH with good accuracy. These results look promising for building an accurate and robust decision system to provide automated assistance to the radiotherapy team in assigning patients to DIBH. [ABSTRACT FROM AUTHOR]

Purpose: Deep inspiration breath hold (DIBH) is used with adjuvant radiation therapy after left breast cancer surgery to reduce radiation dose to the heart. In this study we determined whether thoracic DIBH (T-DIBH) or abdominal DIBH (A-DIBH) should be selected based on patient background. Methods: Three-dimensional conformal radiation therapy plans were created under the same conditions using free breathing (FB), T-DIBH, and A-DIBH CT scans of patients who had previously undergone treatment at our hospital. Results: A-DIBH decreased the left lung dose compared to FB. In comparing T-DIBH and A-DIBH, the heart maximum and left lung doses were significantly lower in A-DIBH. The differences in the heart mean dose (Dmean) between FB, and T-DIBH and A-DIBH were correlated with the cardiothoracic ratio, heart volume, and left lung volume. The difference in the heart Dmean and the left lung dose of T-DIBH and A-DIBH correlated with the forced vital capacity (FVC). Conclusions: A-DIBH is preferable over T-DIBH with respect to the heart and left lung doses; however, with respect to the heart Dmean, T-DIBH was more effective in reducing the dose in some cases, and the FVC was a relevant factor in this study. [ABSTRACT FROM AUTHOR]

Background: Deep inspiration breath hold (DIBH) reduces radiotherapy cardiac dose for left-sided breast cancer patients. The primary aim of the BRAVEHeart (Breast Radiotherapy Audio Visual Enhancement for sparing the Heart) trial is to assess the accuracy and usability of a novel device, Breathe Well, for DIBH guidance for left-sided breast cancer patients. Breathe Well will be compared to an adapted widely available monitoring system, the Real-time Position Management system (RPM). Methods: BRAVEHeart is a single institution prospective randomised trial of two DIBH devices. BRAVEHeart will assess the DIBH accuracy for Breathe Well and RPM during left-sided breast cancer radiotherapy. After informed consent has been obtained, 40 patients will be randomised into two equal groups, the experimental arm (Breathe Well) and the control arm (RPM with in-house modification of an added patient screen). The primary hypothesis of BRAVEHeart is that the accuracy of Breathe Well in maintaining the position of the chest during DIBH is superior to the RPM system. Accuracy will be measured by comparing chest wall motion extracted from images acquired of the treatment field during breast radiotherapy for patients treated using the Breathe Well system and those using the RPM system. Discussion: The Breathe Well device uses a depth camera to monitor the chest surface while the RPM system monitors a block on the patient's abdomen. The hypothesis of this trial is that the chest surface is a better surrogate for the internal chest wall motion used as a measure of treatment accuracy. The Breathe Well device aims to deliver an easy-to-use implementation of surface monitoring. The findings from the study will help inform the technology choice for other centres performing DIBH. Trial registration: ClinicalTrials.govNCT02881203. Registered on 26 August 2016. [ABSTRACT FROM AUTHOR]

Hayley B Stowe,1 Neal D Andruska,1 Francisco Reynoso,1 Maria Thomas,1 Carmen Bergom1– 3 1Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; 2Cardio-Oncology Center of Excellence, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; 3Alvin J. Siteman Center, Washington University School of Medicine in St. Louis, St. Louis, MO, USACorrespondence: Carmen Bergom, Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA, Email cbergom@wustl.eduAbstract: Adjuvant radiation therapy is a critical component of breast cancer management. However, when breast cancer patients receive incidental radiation to the heart, there is an increased risk of cardiac disease and mortality. This is most common for patients with left-sided breast cancers and those receiving nodal irradiation as part of treatment. The overall risk of cardiac toxicity increases 4– 16% with each Gray increase in mean heart radiation dose, with data suggesting that no lower limit exists which would eliminate cardiac risk entirely. Radiation techniques have improved over time, leading to lower cardiac radiation exposure than in the past. This decline is expected to reduce the incidence of radiation-induced heart dysfunction in patients. Deep inspiration breath hold (DIBH) is one such technique that was developed to reduce the risk of cardiac death and coronary events. DIBH is a non-invasive approach that capitalizes on the natural physiology of the respiratory cycle to increase the distance between the heart and the therapeutic target throughout the course of radiation therapy. DIBH has been shown to decrease the mean incidental radiation doses to the heart and left anterior descending coronary artery by approximately 20– 70%. In this review, we summarize different techniques for DIBH and discuss recent data on this technique.Keywords: deep inspiration breath hold, breast cancer, radiation, active breathing control, real-time position management, heart

This study compared the reproducibility of chestwall and heart position using surface‐guided versus RPM (real‐time position management)‐guided deep inspiration breath hold (DIBH) radiotherapy for left sided breast cancer. Forty DIBH patients under either surface‐guided radiotherapy (SGRT) or RPM guidance were studied. For patients treated with tangential fields, reproducibility was measured as the displacements in central lung distance (CLD) and heart shadow to field edge distance (HFD) between pretreatment MV (megavoltage) images and planning DRRs (digitally reconstructed radiographs). For patients treated with volumetric modulated arc therapy (VMAT), sternum to isocenter (ISO) distance (StID), spine to rib edge distance (SpRD), and heart shadow to central axis (CAX) distance (HCD) between pretreatment kV images and planning DRRs were measured. These displacements were compared between SGRT and RPM‐guided DIBH. In tangential patients, the mean absolute displacements of SGRT versus RPM guidance were 0.19 versus 0.23 cm in CLD, and 0.33 versus 0.62 cm in HFD. With respect to planning DRR, heart appeared closer to the field edge by 0.04 cm with surface imaging versus 0.62 cm with RPM. In VMAT patients, the displacements of surface imaging versus RPM guidance were 0.21 versus 0.15 cm in StID, 0.24 versus 0.19 cm in SpRD, and 0.72 versus 0.41 cm in HCD. Heart appeared 0.41 cm further away from CAX with surface imaging, whereas 0.10 cm closer to field CAX with RPM. None of the differences between surface imaging and RPM guidance was statistically significant. In conclusion, the displacements of chestwall were small and were comparable with SGRT‐ or RPM‐guided DIBH. The position deviations of heart were larger than those of chestwall with SGRT or RPM. Although none of the differences between SGRT and RPM guidance were statistically significant, there was a trend that the position deviations of heart were smaller and more favorable with SGRT than with RPM guidance in tangential patients. [ABSTRACT FROM AUTHOR]

Purpose: Beam gating with deep inspiration breath hold (DIBH) usually depends on some external surrogate to infer internal target movement, and the exact internal movement is unknown. In this study, we tracked internal targets and characterized residual motion during DIBH treatment, guided by a surface imaging system, for gastrointestinal cancer. We also report statistics on treatment time. Methods and materials: We included 14 gastrointestinal cancer patients treated with surface imaging‐guided DIBH volumetrically modulated arc therapy, each with at least one radiopaque marker implanted near or within the target. They were treated in 25, 15, or 10 fractions. Thirteen patients received treatment for pancreatic cancer, and one underwent separate treatments for two liver metastases. The surface imaging system monitored a three‐dimensional surface with ± 3 mm translation and ± 3° rotation threshold. During delivery, a kilovolt image was automatically taken every 20° or 40° gantry rotation, and the internal marker was identified from the image. The displacement and residual motion of the markers were calculated. To analyze the treatment efficiency, the treatment time of each fraction was obtained from the imaging and treatment timestamps in the record and verify system. Results: Although the external surface was monitored and limited to ± 3 mm and ± 3°, significant residual internal target movement was observed in some patients. The range of residual motion was 3–21 mm. The average displacement for this cohort was 0–3 mm. In 19% of the analyzed images, the magnitude of the instantaneous displacement was > 5 mm. The mean treatment time was 17 min with a standard deviation of 4 min. Conclusions: Precaution is needed when applying surface image guidance for gastrointestinal cancer treatment. Using it as a solo DIBH technique is discouraged when the correlation between internal anatomy and patient surface is limited. Real‐time radiographic verification is critical for safe treatments. [ABSTRACT FROM AUTHOR]

Background and Purpose: &#xD;This study presents machine learning (ML) models that predict if deep inspiration breath hold (DIBH) is needed based on lung dose in right-sided breast cancer patients during the initial computed tomography (CT) appointment. &#xD;Materials and methods. &#xD;Anatomic distances were extracted from a single-institution dataset of free breathing (FB) CT scans from locoregional right-sided breast cancer patients. Models were developed using combinations of anatomic distances and ML classification algorithms (gradient boosting, k-nearest neighbors, logistic regression, random forest, and support vector machine) and optimized over 100 iterations using stratified 5-fold cross-validation. Models were grouped by the number of anatomic distances used during development; those with the highest validation accuracy were selected as final models. Final models were compared based on their predictive ability, measurement collection efficiency, and robustness to simulated user error during measurement collection. &#xD;Results. &#xD;This retrospective study included 238 patients treated between 2016 and 2021. Model development ended once eight anatomic distances were included, and the validation accuracy plateaued. The best performing model used logistic regression with four anatomic distances achieving 80.5% average testing accuracy, with minimal false negatives and positives (< 27%). The anatomic distances required for prediction were collected within 3 minutes and were robust to simulated user error during measurement collection, changing accuracy by < 5%. &#xD;Conclusion. &#xD;Our logistic regression model using four anatomic distances provided the best balance between efficiency, robustness, and ability to predict if DIBH was needed for locoregional right-sided breast cancer patients.&#xD., (Creative Commons Attribution license.)

This paper aims to provide guidance and a framework for commissioning tests and tolerances for the ExacTrac Dynamic image-guided and surface-guided radiotherapy (SGRT) system. ExacTrac Dynamic includes a stereoscopic X-ray system, a structured light projector, stereoscopic cameras, thermal camera for SGRT, and has the capability to track breath holds and internal markers. The system provides fast and accurate image guidance and intrafraction guidance for stereotactic radiosurgery and stereotactic ablative radiotherapy. ExacTrac Dynamic was commissioned on a recently installed Elekta Versa HD. Commissioning tests are described including safety, isocenter calibration, dosimetry, image quality, data transfer, SGRT stability, SGRT localization, gating, fusion, implanted markers, breath hold, and end-to-end testing. Custom phantom designs have been implemented for assessment of the deep inspiration breath-hold workflow, the implanted markers workflow, and for gating tests where remote-controlled movement of a phantom is required. Commissioning tests were all found to be in tolerance, with maximum translational and rotational deviations in SGRT of 0.3 mm and 0.4°, respectively, and X-ray image fusion reproducibility standard deviation of 0.08 mm. Tolerances were based on published documents and upon the performance characteristics of the system as specified by the vendor. The unique configuration of ExacTrac Dynamic requires the end user to design commissioning tests that validate the system for use in the clinical implementation adopted in the department. As there are multiple customizable workflows available, tests should be designed around these workflows, and can be ongoing as workflows are progressively introduced into departmental procedures.

This paper aims to provide guidance and a framework for commissioning tests and tolerances for the ExacTrac Dynamic image‑guided and surface‑guided radiotherapy (SGRT) system. ExacTrac Dynamic includes a stereoscopic X‑ray system, a structured light projector, stereoscopic cameras, thermal camera for SGRT, and has the capability to track breath holds and internal markers. The system provides fast and accurate image guidance and intrafraction guidance for stereotactic radiosurgery and stereotactic ablative radiotherapy. ExacTrac Dynamic was commissioned on a recently installed Elekta Versa HD. Commissioning tests are described including safety, isocenter calibration, dosimetry, image quality, data transfer, SGRT stability, SGRT localization, gating, fusion, implanted markers, breath hold, and end‑to‑end testing. Custom phantom designs have been implemented for assessment of the deep inspiration breath‑hold workflow, the implanted markers workflow, and for gating tests where remote‑controlled movement of a phantom is required. Commissioning tests were all found to be in tolerance, with maximum translational and rotational deviations in SGRT of 0.3 mm and 0.4°, respectively, and X‑ray image fusion reproducibility standard deviation of 0.08 mm. Tolerances were based on published documents and upon the performance characteristics of the system as specified by the vendor. The unique configuration of ExacTrac Dynamic requires the end user to design commissioning tests that validate the system for use in the clinical implementation adopted in the department. As there are multiple customizable workflows available, tests should be designed around these workflows, and can be ongoing as workflows are progressively introduced into departmental procedures. [ABSTRACT FROM AUTHOR]

The aim of TROG 14.04 was to assess the feasibility of deep inspiration breath hold (DIBH) and its impact on radiation dose to the heart in patients with left-sided breast cancer undergoing radiotherapy. Secondary end points pertained to patient anxiety and cost of delivering a DIBH programme. The study comprised two groups – left-sided breast cancer patients engaging DIBH and right-sided breast cancer patients using free breathing through radiotherapy. The primary end point was the feasibility of DIBH, defined as left-sided breast cancer patients' ability to breath hold for 15 s, decrease in heart dose in DIBH compared with the free breathing treatment plan and reproducibility of radiotherapy delivery using mid-lung distance (MLD) assessed on electronic portal imaging as the surrogate. The time required for treatment delivery, patient-reported outcomes and resource requirement were compared between the groups. Between February and November 2018, 32 left-sided and 30 right-sided breast cancer patients from six radiotherapy centres were enrolled. Two left-sided breast cancer patients did not undergo DIBH (one treated in free breathing as per investigator choice, one withdrawn). The mean heart dose was reduced from 2.8 Gy (free breathing) to 1.5 Gy (DIBH). Set-up reproducibility in the first week of treatment assessed by MLD was 1.88 ± 1.04 mm (average ± 1 standard deviation) for DIBH and 1.59 ± 0.93 mm for free breathing patients. Using a reproducibility cut-off for MLD of 2 mm (1 standard deviation) as per study protocol, DIBH was feasible for 67% of DIBH patients. Radiotherapy delivery using DIBH took about 2 min longer than for free breathing. Anxiety was not significantly different in DIBH patients and decreased over the course of treatment in both groups. Although DIBH was shown to require about 2 min longer per treatment slot, it has the potential to reduce heart dose in left-sided breast cancer patients by nearly a half, provided careful assessment of breath hold reproducibility is carried out. • Deep inspiration breath hold (DIBH) was assessed in a prospective, multicentre trial as a means of reproducibly reducing dose to the heart. • DIBH was confirmed in plans of 30 patients from six institutions to reduce dose to the heart by about 45% compared with free breathing. • DIBH added about 2 min to the treatment time compared with right-sided breast patients treated in the same institutions using free breathing. • There was no difference in anxiety assessed on a visual analogue scale between DIBH patients compared with free breathing patients. [ABSTRACT FROM AUTHOR]

To evaluate the dosimetric advantages of incorporating the deep inspiration breath hold (DIBH) technique into left breast cancer volumetric modulated arc therapy (VMAT) treatment under Halcyon Linac and to investigate the correlation between mean heart dose (MHD) and distance from the heart to target volumes in left breast cancer VMAT treatment. Fifteen Post-lumpectomy, left-sided breast patients treated between January 2017 and October 2020 were selected. Two plans were generated for each patient using Eclipse treatment planning system (TPS) with the prescription of 50.4 Gy to planning target volume (PTV) breast and 58.8 Gy to PTV boost in 28 fractions. For each patient, DIBH and free breathing (FB) VMAT treatment plans under Halcyon Linac were generated. Dosimetric parameters, monitor unit and beam-on time of both DIBH and FB groups were compared. Three-dimensional distances from heart surface to each target volume were measured on computed tomography images using the TPS contouring tool and their correlation with MHD was evaluated by Pearson's correlation coefficient (r). Comparable target coverage was shown in both groups. Mean dose to heart, left anterior descending artery, and left ventricle in Halcyon-DIBH-VMAT group were significantly reduced by 0.49 Gy, 1.19 Gy, and 0.57 Gy, respectively, compared to Halcyon-FB-VMAT (p < 0.001). A significant lung dose reduction was also achieved in Halcyon-DIBH-VMAT group. There was also a strong negative correlation between MHD and distance from heart surface to PTV boost in both FB and DIBH group (r = −0.741, p < 0.001), but not observed for distance from heart surface to PTV breast. Incorporating DIBH into left breast cancer VMAT treatment under Halcyon Linac demonstrated significant cardiac and lung dose reduction. It was also demonstrated that MHD had a strong negative correlation with distance from heart surface to PTV boost but relatively independent of distance from heart surface to PTV breast. Recognizing the distance from the heart surface to PTV boost as the main factor in affecting MHD could potentially facilitate clinical treatment planning workflow and decision. [ABSTRACT FROM AUTHOR]

Breast with supraclavicular fossa (Br+SCF) radiotherapy treatments can utilise a monoisocentric technique to concurrently treat the breast area (tangent fields) and supraclavicular area (opposing fields). The region where these treatment areas adjoin is known as the junction region, field junction, or match line. Dose variations that may occur about the junction region, due to geometrical inaccuracies, are typically feathered out in patient free-breathing treatments. However, there is limited information on how dose at the junction is influenced in deep inspiration breath hold (DIBH) treatments. This study aims to investigate dose variation at the field junction for a patient population undertaking a DIBH Br+SCF treatment course. GAFChromic EBT3 film was used to record the dose across the junction at skin surface for approximately one third of the 25 fraction treatment course for 11 patients undergoing DIBH Br+SCF treatment. Single fraction and summated fraction profiles for each patient were compared to profiles in the treatment planning system and assessed the: (1) local dose variations, (2) position of the 50% dose gradient, and (3) relative dose at the nominal junction. Local dose variations of 10% or greater, position displacement of the junction greater than 5 mm, and relative dose differences at the match line greater than 10% can be found within single fraction dose profiles. When these single fractions are summed over the treatment course, the position variations reduce to 2 mm and dose variations reduced to within 10% for 10 of the 11 patients. Only one of 11 patients recorded a summed dose difference greater than ±10% over their treatment, recording 76% ± 8% of the planned dose in this region. This was due to a small overall position displacement of 1.8 ± 1.6 mm from the nominal junction. A feathering of the dose at the junction is present for DIBH Br+SCF patient treatments. The feathering effect is sufficient, in the majority of cases studied, to reduce any differences in dose and displacement present in single fractions. This work also demonstrates that there may be exceptions from this observed behavior that should be considered. Further study in this area using a larger patient cohort is recommended. [ABSTRACT FROM AUTHOR]

Many institutions worldwide currently deliver left breast radiotherapy in free breathing mode, mostly due to the unavailability of a Deep Inspiration Breath Hold technique (DIBH). This study aims at quantifying the error in dose delivery (compared to treatment plan) due to respiratory motion in free breathing irradiation of left breast or chest wall. Since subfields often consist in small, fine-tuned, highly targeted fields, slight intrafractional target motion may compromise their subtle benefit. Thus we analyzed the respiratory motion effect on target dose coverage, dose homogeneity and left lung dose. Treatment plans for twenty left breast or chest wall cancer patients previously treated at our center were retrieved and retrospectively planned with the introduction of an appropriate shift in isocenter location to simulate free breathing target motion. No clinically significant dosimetric changes were found in all twenty cases when breathing motion was accounted for. Changes in target dose coverage (V95%), in target maximum dose (D2%) and in V20Gy lung dose were respectively less than 1.5%, 0.3% and 2.6%. The findings suggest that breast irradiation in free breathing mode does not undermine the dosimetric merits of the field-in-field technique and does not produce clinically significant dosimetric differences in dose delivery for target and lung compared to plan. • Breathing has a negligible effect on dose delivery accuracy in breast cancer radiotherapy. • Free breathing during breast radiotherapy treatment does not invalidate the use of field-in-field technique. • The dosimetric error from free breathing breast motion during radiotherapy treatment is clinically negligible. [ABSTRACT FROM AUTHOR]

Patients with left breast cancer who undergo radiotherapy have a non-negligible risk of developing radiation-induced cardiovascular disease (CVD). Cardioprotection can be achieved through better treatment planning protocols and through respiratory gating techniques, including deep inspiration breath hold (DIBH). Several dosimetric studies have shown that DIBH reduces the cardiac dose, but clinical data confirming this effect is limited. The aim of the study was to compare the mean heart dose (MHD) in patients with left breast cancer who underwent radiotherapy at our institution as we transitioned from non-gated free-breathing (FB) radiotherapy to gated radiotherapy (FB-GRT), and finally to DIBH.

Objectives: Modern breast cancer techniques, such as the deep inspiration breath-hold (DIBH) technique has been applied for left-sided breast cancer. Whether the DIBH regimen is the optimal solution for left-sided breast cancer remains unclear. This meta-analysis aims to elucidate the differences of DIBH and free-breathing (FB) for patients receiving radiotherapy for left-sided breast cancer and provide a practical reference for clinical practice. Methods: Relevant research available on PubMed, Embase, Cochrane Library, and the Web of Science published before November 30, 2021 was independently and systematically examined by two investigators. Data were extracted from eligible studies for assessing their qualities and calculating the standardized mean difference (SMD) and 95% confidence intervals (CIs) using Review Manager software 5.4 (RevMan 5.4). Results: Forty-one studies with a total of 3599 left-sided breast cancer patients were included in the meta-analysis. Compared with FB, DIBH reduced heart dose (D mean, D max, V30, V10, V5), left anterior descending branch (LAD) dose (D mean, D max), ipsilateral lung dose (D mean, V20, V10, V5), and heart volume significantly. Lung volume increased greatly, and a statistically significant difference. For contralateral breast mean dose, DIBH has no obvious advantage over FB. The funnel plot suggested this study has no significant publication bias. Conclusions: Although DIBH has no obvious advantage over FB in contralateral breast mean dose, it can significantly reduce heart dose, LAD dose, ipsilateral lung dose, and heart volume. Conversely, it can remarkably increase the ipsilateral lung volume. This study suggests that soon DIBH could be more widely utilized in clinical practice because of its excellent dosimetric performance. [ABSTRACT FROM AUTHOR]

Significant advances in technology have allowed radiation therapy to be administered in a way that minimizes cardiac dose and the risk of late cardiovascular complications while providing tumor control. Various treatment methods can be used to reduce the heart dose in the treatment of breast cancer and thoracic tumors with radiation. Deep inspiration breath hold technique, application of radiotherapy in the prone position, accelerated partial breast irradiation are frequently used methods in the treatment of breast cancer. Intensity-modulated radiotherapy and proton therapy have been shown to reduce the cardiac dose in many diseases such as breast cancer, lung cancer, esophageal cancer, mesothelioma, bilateral lung irradiation, lymphoma, and craniospinal irradiation. The best cardioprotective technique should be used by evaluating patient characteristics (age, comorbid diseases, and patient's anatomy) and technical possibilities. [ABSTRACT FROM AUTHOR]

Deep inspiration breath hold (DIBH) has dosimetric advantages for lung cancer patients treated with external beam therapy, but is difficult for many patients to perform. Proton therapy permits sparing of the downstream organs at risk (OAR). We compared conventionally fractionated proton (p) and photon(x) plans on both free breathing (FB) and DIBH planning CTs to determine the effect of DIBH with proton therapy. We evaluated 24 plans from 6 lung cancer patients treated with photon DIBH on a prospective protocol. All patients were re-planned using pencil beam scanning (PBS) proton therapy. New plans were generated for FB datasets with both modalities. All plans were renormalized to 60 Gy. We evaluated dosimetric parameters for heart, lung and esophagus. We also compared FB p to DIBH x parameters to quantify how FB p plans compare to DIBH x plans. Significant differences were found for lung metrics V20 and mean lung dose between FB and DIBH plans regardless of treatment modality. Furthermore, lung metrics for FB p were comparable or superior to DIBH x , suggesting that FB protons may be a viable alternative for those patients that cannot perform DIBH with IMRT. The heart dose metrics were significantly different for the 5 out of 6 patients where the PTV overlapped the heart as DIBH moved heart out of the high dose volume. Heart dose metrics were further reduced by proton therapy. DIBH offers similar relative advantages for lung sparing for PBS as it does for IMRT but the magnitude of the DIBH related gains in OAR sparing were smaller for PBS than IMRT. FB p plans offer similar or better lung and heart sparing compared to DIBH x plans. For IMRT patients who have difficulty performing DIBH, FB protons may offer an alternative. [ABSTRACT FROM AUTHOR]

Introduction: One of the most feared side effects of radiotherapy (RT) in the setting of breast cancer (BC) patients is cardiac toxicity. This side effect can jeopardize the quality of life (QoL) of long-term survivors. The impact of modern techniques of RT such as deep inspiration breath hold (DIBH) have dramatically changed this setting. We report and discuss the results of the literature overview of this paper. Materials and methods: Literature references were obtained with a PubMed query, hand searching, and clinicaltrials.gov. Results: We reported and discussed the toxicity of RT and the improvements due to the modern techniques in the setting of BC patients. Conclusions: BC patients often have a long life expectancy, thus the RT should aim at limiting toxicities and at the same time maintaining the same high cure rates. Further studies are needed to evaluate the risk–benefit ratio to identify patients at higher risk and to tailor the treatment choices. [ABSTRACT FROM AUTHOR]

Vision-RT system is one of the most effective methods for real-time estimation of target location in external beam radiotherapy. Vision-RT tracks the patient’s surface before and during radiation therapy to improve treatment accuracy. Using proprietary 3D stereo camera units, Vision-RT system tracks the skin surface, compares it to the ideal position, and can automatically signal to the treatment delivery system. The purpose of this study is to investigate the accuracy of Vision RT guided deep inspiration breath-hold left-sided breast cancer radiotherapy. Five patients with left-sided breast cancer were treated by Vision RT guided deep inspiration breath-hold at Aarhus university hospital. Based on the results, in one out of five patients, the undesired heart extended to 0.6-0.9 cm into the treatment fields in 5 out of 15 treatment fractions. Moreover, the required PTV margin to account for patient setup error and intra-fractional error of the first and second treatment field was 2.38 mm, 3 mm and 4.12 mm, respectively.

ObjectivesModern breast cancer techniques, such as the deep inspiration breath-hold (DIBH) technique has been applied for left-sided breast cancer. Whether the DIBH regimen is the optimal solution for left-sided breast cancer remains unclear. This meta-analysis aims to elucidate the differences of DIBH and free-breathing (FB) for patients receiving radiotherapy for left-sided breast cancer and provide a practical reference for clinical practice.MethodsRelevant research available on PubMed, Embase, Cochrane Library, and the Web of Science published before November 30, 2021 was independently and systematically examined by two investigators. Data were extracted from eligible studies for assessing their qualities and calculating the standardized mean difference (SMD) and 95% confidence intervals (CIs) using Review Manager software 5.4 (RevMan 5.4).ResultsForty-one studies with a total of 3599 left-sided breast cancer patients were included in the meta-analysis. Compared with FB, DIBH reduced heart dose (Dmean, Dmax, V30, V10, V5), left anterior descending branch (LAD) dose (Dmean, Dmax), ipsilateral lung dose (Dmean, V20, V10, V5), and heart volume significantly. Lung volume increased greatly, and a statistically significant difference. For contralateral breast mean dose, DIBH has no obvious advantage over FB. The funnel plot suggested this study has no significant publication bias.ConclusionsAlthough DIBH has no obvious advantage over FB in contralateral breast mean dose, it can significantly reduce heart dose, LAD dose, ipsilateral lung dose, and heart volume. Conversely, it can remarkably increase the ipsilateral lung volume. This study suggests that soon DIBH could be more widely utilized in clinical practice because of its excellent dosimetric performance.

Purpose: to predict eligibility for deep inspiration breath-hold (DIBH) radiotherapy (RT) treatment of patients with left breast cancer from analysis of respiratory signal, using Deep Bidirectional Long Short-Term Memory (BLSTM) recurrent neural networks. Methods: The respiratory traces from 36 patients who underwent DIBH RT were collected. The patients’ RT treatment plans were generated for both DIBH and free-breathing (FB) modalities. The patients were divided into two classes (patient eligible or not), based on the decrease of maximum dose to the left anterior descending (LAD) artery achieved with DIBH, compared to that achieved with FB and ΔDL. Patients with ΔDL > median value of ΔDL within the patient cohort were assumed to be those selected for DIBH. A BLSTM-RNN was trained for classification of patients eligible for DIBH by analysis of their respiratory signals, as acquired during acquisition of the pre-treatment computed tomography (CT), for selecting the window for DIBH. The dataset was split into training (60%) and test groups (40%), and the hyper-parameters, including the number of hidden layers, the optimizer, the learning rate, and the number of epochs, were selected for optimising model performance. The BLSTM included 2 layers of 100 neural units, each followed by a dropout layer with 20% dropout, and was trained in 35 epochs using the Adam optimizer, with an initial learning rate of 0.0003. Results: The system achieved accuracy, specificity, and sensitivity of, F1 score and area under the receiving operating characteristic curve (AUC) of 71.4%, 66.7%, 80.1%, 72.4%, and 69.4% in the test dataset, respectively. Conclusions: The proposed BLSTM-RNN classified patients in the test set eligible for DIBH with good accuracy. These results look promising for building an accurate and robust decision system to provide automated assistance to the radiotherapy team in assigning patients to DIBH.

Background: In the context of left breast cancer radiotherapy, long term cardiopulmonary toxicity has been well-documented, significant efforts have been undertaken to mitigate such toxicity by using 4D gating, deep inspiration breath-hold(DIBH) and active breath control(ABC) techniques., Purpose: To evaluate and compare the cardio-pulmonary radiation doses incurred during postmastectomy radiotherapy (PMRT) in two distinct breathing conditions such as DIBH and Free Breathing (FB), with a specific focus on the left chest wall with comprehensive regional nodal irradiation., Materials and Methods: A prospective dosimetric study was conducted on 15 patients who received adjuvant loco-regional radiotherapy of chest-wall (CW), supraclavicular fossa(SCF), and internal mammary region(IMC), with or without axilla. Two sets of planning CT scans were taken in DIBH and FB conditions. The dosimetric difference between DIBH CT and FB CT plans analyzed using Wilcoxon signed-rank test, employing SPSS software version 21.0., Results: Comparison of DIBH and FB parameters for target coverage revealed a statistically significant advantage with DIBH in SCF(D95, V90, p<0.017) and IMC(D98, V90 & V95, p<0.03). Dosimetric characteristics of heart and LAD exhibited statistically significant lower doses with DIBH (V20, V25, and Dmean, p<0.001) compared to FB plans. Lung doses were similar with no discernible advantage of one technique over the other. Other OARs such as contralateral breast (p=0.027) and esophagus (p=0.001) received lower doses with the DIBH technique while the spinal cord (p=0.691) and thyroid(p=0.496) showed no significant difference. Maximum heart distance (p= 0.001), central lung distance (p= 0.011) and Haller index (p= 0.001) exhibited statistical significance between the two techniques, whereas chest wall separation showed no significant statistical difference (p=0.629)., Conclusion: DIBH demonstrates a substantial reduction in cardiac and LAD doses compared to the FB technique. This study underscores the efficacy of DIBH as a viable strategy for mitigating cardiac and LAD radiation doses in left-sided breast cancer patients undergoing PMRT of chest wall with comprehensive regional nodes.

Background: The present study was to investigate the usefulness of deep inspiration breath hold (DIBH) in bilateral breast patients using 6MV flattened beam (FB) and flattening filter free beam (FFFB). Materials and methods: Twenty bilateral breast cancer patients were simulated, using left breast patients treated with DIBH technique. CT scans were performed in the normal breathing (NB) and DIBH method. Three-dimensional conformal radiotherapy (3DCRT) and volumetric arc therapy (VMAT) plans were generated. Results: In our study the best organ at risk (OAR) sparing is achieved in the 3DCRT DIBH plan with adequate PTV coverage (V95 ≥ 47.5 Gy) as compared to 6MV FB and FFFB VMAT DIBH plans. The DIBH scan plan reduces the heart mean dose significantly at the rate of 49% in 3DCRT (p = 0.00) and 22% in VMAT (p = 0.010). Similarly, the DIBH scan plan produces lesser common lung mean dose of 18% in 3DCRT (p = 0.011) and 8% in VMAT (0.007) as compared to the NB scan. The conformity index is much better in VMAT FB (1.04 ± 0.04 vs. 1.04 ± 0.05), p =1.00 and VMAT FFFB (1.04 ± 0.05 vs. 1 ± 0.24, p = 0.345) plans as compared to 3DCRT (1.63 ± 0.2 vs. 1.47 ± 0.28, p = 0.002). The homogeneity index of all the plans is less than 0.15. The global dmax is more in VMAT FFFB DIBH plan (113.7%). The maximum MU noted in the NB scan plan (478 vs. 477MU, 1366 vs. 1299 MU and 1853 vs. 1788 MU for 3DCRT, VMAT FB and VMAT FFFB technique as compared to DIBH scan. Conclusion: We recommend that the use of DIBH techniques for bilateral breast cancer patients significantly reduces the radiation doses to OARs in both 3DCRT and VMAT plans. [ABSTRACT FROM AUTHOR]

The purpose of this case study is to describe an external beam radiation therapy planning technique for carcinoma of the left breast. A female patient on protocol NSABP B-51/RTOG 1304 presented with unusual anatomy and large habitus. Deep inspiration breath-hold (DIBH) IMRT was used in conjunction a DIBH-3D conformal radiotherapy (3DCRT) tangential boost plan to meet the dose criteria for protocol compliance. Traditionally 3DCRT planning using a DIBH technique would be used for both billing authorization and as DIBH-IMRT involves a longer treatment time and more difficulty in terms of patient compliance; however, the patient tolerated the treatment very well. The subsequent treatment plan met all criteria per protocol with the exception of the ipsilateral lung, which passed with acceptable variation. [ABSTRACT FROM AUTHOR]

Background: Dosimetric parameters of the planning target volume (PTV) and organs at risk (OARs) were compared among 3 different radiotherapy (RT) modalities in left breast cancer patients after breast-conserving surgery (BCS). Methods: Eleven patients with left breast cancer after BCS were enrolled and underwent CT simulation in the free breathing (FB) and deep inspiration breath-hold (DIBH) position. Three-dimensional conformal RT (3DCRT) and volumetric modulated arc therapy (VMAT) plans were generated for each patient in the DIBH positions. A 3DCRT plan was also created in the FB position. A dose-volume histogram (DVH) was used to analyze each evaluation index of PTV and OARs. The principal outcomes were PTV dose, heart dose, right breast dose, left anterior descending coronary artery (LADCA) dose, and left lung dose. Results: For 3DCRT plans, significant dose reductions were demonstrated in all evaluation parameters of the heart, LADCA, and left lung doses in the DIBH position compared with those in the FB position (P < 0.05). In the DIBH position, significant dose reductions were found in the heart and LADCA in VMAT plans compared to those in 3DCRT plans (P < 0.05). For the right breast, VMAT reduced Dmean significantly (0.32 Gy vs 0.08 Gy, P < 0.01). There were no significant differences between 3DCRT and VMAT plans for the left lung dose in the DIBH position. The indicators of PTV had no significant difference between the 3 plans. Conclusion: DIBH and VMAT could reduce dosimetric parameters of the OARs in left breast cancer patients after BCS. RT plans for left breast cancer after BCS can be optimized by DIBH and VMAT techniques to minimize radiation-induced toxicity. [ABSTRACT FROM AUTHOR]

• Multi-atlases can be used for contouring of cardiac structures in planning CT scans. • Atlas accuracy was at least similar to interobserver delineation variation. • Atlas performance depends on the breathing technique used in planning CT scans. • Separate atlases for scans made in DIBH and FB could benefit atlas performance. Developing NTCP-models for cardiac complications after breast cancer (BC) radiotherapy requires cardiac dose-volume parameters for many patients. These can be obtained by using multi-atlas based automatic segmentation (MABAS) of cardiac structures in planning CT scans. We investigated the relevance of separate multi-atlases for deep inspiration breath hold (DIBH) and free breathing (FB) CT scans. BC patients scanned in DIBH (n = 10) and in FB (n = 20) were selected to create separate multi-atlases consisting of expert panel delineations of the whole heart, atria and ventricles. The accuracy of atlas-generated contours was validated with expert delineations in independent datasets (n = 10 for DIBH and FB) and reported as Dice coefficients, contour distances and dose-volume differences in relation to interobserver variability of manual contours. Dependency of MABAS contouring accuracy on breathing technique was assessed by validation of a FB atlas in DIBH patients and vice versa (cross-validation). For all structures the FB and DIBH atlases resulted in Dice coefficients with their respective reference contours ≥ 0.8 and average contour distances ≤ 2 mm smaller than slice thickness of (CTs). No significant differences were found for dose-volume parameters in volumes receiving relevant dose levels (WH, LV and RV). Accuracy of the DIBH atlas was at least similar to, and for the ventricles better than, the interobserver variation in manual delineation. Cross-validation between breathing techniques showed a reduced MABAS performance. Multi-atlas accuracy was at least similar to interobserver delineation variation. Separate atlases for scans made in DIBH and FB could benefit atlas performance because accuracy depends on breathing technique. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate thoracic surface motion from chest wall expansion during free breathing (FB) and deep inspiration breath hold (DIBH) methods, measured with and without 4-dimensional computed tomography (4D-CT) simulation, using equipment developed in-house. The respiratory amplitude and chest wall expansion were evaluated at 5 levels of the thorax, (the sterno-clavicular joint (SCJ), the second level, the intermammary line (IML), the fourth level and the caudal end of the xiphoid process (XP)) using radiopaque wires and potentiometers, with a CT scan simultaneously. This study included 25 examinees (10 volunteers performed FB, 10 volunteers performed DIBH and 5 patients performed FB). For low and irregular respiration, coaching was used, and its impact was evaluated for both breathing methods, FB and DIBH. The breathing amplitude performed with FB between volunteers and patients was not detectable at the SCJ; increasing to the abdomen, 3 mm vs 2 mm (p = 0.326) at the second level; 6 mm vs 4 mm (p = 0.042) at the IML; 10 mm vs 8 mm (p < 0.01) at the fourth level; and 23 mm vs 19 mm (p < 0.001) at the XP. Contrary to the DIBH, where breathing amplitude was greater at 2 first levels 18 mm (SCJ) and 20 mm (second level), decreasing to the abdomen, 14 mm (IML); 11 mm (fourth level); and 10 mm (XP). Chest wall expansion was not detected at the SCJ, while at other levels measured from 1 to 7 mm. Coaching was improve breathing amplitude, for both methods, FB (3 mm) and DIBH (5 mm). The location of amplification is different depending on the breathing method and the in-house phantom was useful to check the amplification level. [ABSTRACT FROM AUTHOR]

Background: The deep inspiration breath hold (DIBH) technique is effective for heart dose reduction in patients with left-sided breast cancer. In deep breathing, some women breathe in thoracic respiration; and others, in abdominal respiration. This study evaluated differences in dose reduction in organs at risk (OAR) and reproducibilities of the target and OAR between thoracic DIBH (T-DIBH) and abdominal DIBH (A-DIBH). Methods: Fourteen patients with left-sided breast cancer who had planned to receive whole-breast irradiation were included. Computed tomography (CT) was performed in free breathing (FB), T-DIBH, and A-DIBH, and the dosimetric indexes of the target and OAR for three treatment plans were compared. In T-DIBH and A-DIBH, two series CTs were taken in each breathing method and the displacements of the target and heart were calculated. Results: The averaged mean heart doses (MHDs) were 1.5 Gy and 1.6 Gy in T-DIBH and A-DIBH, respectively, significantly lower than 2.7 Gy in FB (p < 0.001 for both breathing methods). Between T-DIBH and A-DIBH, no significant difference in MHD was found (p = 0.95); however, the percentage increase in lung volume positively moderately correlated with the reduction in MHD (R = 0.68). The three-dimensional target displacements were 2.3 mm in T-DIBH and 2.0 mm in A-DIBH (p = 0.64). The three-dimensional heart displacements were 1.7 mm in T-DIBH and 1.8 mm in A-DIBH (p = 0.85). Conclusion: The present study demonstrates that the MHD and reproducibility did not differ between T-DIBH and A-DIBH. However, the superior breathing method for increasing lung volume should be determined for each patient. [ABSTRACT FROM AUTHOR]

Abstract Background Adjuvant radiotherapy is the standard treatment after breast-conserving surgery. According to meta-analyses, adjuvant 3d-conventional irradiation reduces the risk of local recurrence and thereby improves long-term survival by 5–10%. However, there is an unintended exposure of organs such as the heart, lungs and contralateral breast. Irradiation of the left breast has been related to long-term effects like increased rates of coronary events as well as second cancer induction. Modern radiotherapy techniques such as tangential intensity modulated radiotherapy (t-IMRT) and tangential volumetric modulated arc therapy (t-VMAT) and particularly deep inspiration breath hold (DIBH) technique have been developed in order to improve coverage of target volume and to reduce dose to normal tissue. The aim of this study was to compare t-IMRT-plans with t-VMAT-plans in DIBH position for left-sided breast irradiation in terms of normal tissue exposure, i.e. of lungs, heart, left anterior descending coronary artery (LADCA), as well as homogeneity (HI) and conformity index (CI) and excess absolute risk (EAR) for second cancer induction for organs at risk (OAR) after irradiation. Methods Twenty patients, diagnosed with left-sided breast cancer and treated with breast-preserving surgery, were included in this planning study. For each patient DIBH-t-IMRT plan using 5 to 7 beams and t-VMAT plan using four rotations were generated to achieve 95% dose coverage to 95% of the volume. Data were evaluated on the basis of dose-volume histograms: Cardiac dose and LADCA (mean and maximum dose, D25% and D45%), dose to ipsilateral and contralateral lung (mean, D20%, D30%), dose to contralateral breast (mean dose), total monitor units, V5% of total body and normal tissue integral dose (NTID). In addition, homogeneity index and conformity index, as well as the excess absolute risk (EAR) to estimate the risk of second malignancy were calculated. Results T-IMRT showed a significant reduction in mean cardiac dose of 26% (p = 0.002) compared to t-VMAT, as well as a significant reduction in the mean dose to LADCA of 20% (p = 0.03). Following t-IMRT, mean dose to the left lung was increased by 5% (p = 0.006), whereas no significant difference was found in the mean dose to the right lung and contralateral breast between the two procedures. Monitor units were 31% (p = 0.000004) lower for t-IMRT than for t-VMAT. T-IMRT technique significantly reduced normal tissue integral dose (NTID) by 19% (p = 0.000005) and the V5% of total body by 24% (p = 0.0007). In contrast, t-VMAT improved CI and HI by 2% (p = 0.001) and 0.4% (p = 0.00001), respectively. EAR with t-IMRT was significantly lower, especially for contralateral lung and contralateral breast (2–5/10,000 person years) but not for ipsilateral lung. Conclusion Compared to t-VMAT, t-IMRT in left-sided breast irradiation significantly reduced dose to organs at risk as well as normal tissue integral dose, and V5% total body. EAR with t-IMRT was significantly lower for contralateral lung and contralateral breast. T-VMAT, however, achieved better homogeneity and conformity. This may be relevant in individual cases where sufficient coverage of medial lymphatic target volumes is warranted.

Abstract Background Although there have been many attempts to increase the therapeutic ratio of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), only a few planning studies have reported the efficacy of the modern radiotherapy technique till date. Therefore, we performed the dosimetric comparison among 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) plans, using deep-inspiration breath hold (DIBH) or free-breathing (FB) techniques, to determine the most optimal plan for gastric MALToma. Methods We evaluated 9 patients with gastric MALToma for whom 3D-CRT, step-and-shoot IMRT (SIMRT), volumetric-modulated arc therapy (VMAT), and tomotherapy plans with identical prescribed doses were generated using DIBH or FB computed tomography (CT). Planning target volume (PTV) coverage and non-target doses were calculated for each plan and compared with plan quality metric (PQM) scores. Results All 72 plans of 9 patients satisfied our dosimetric goals, and the IMRT plans and 3D-CRT plans had similarly good conformity index values with no differences related to respiratory movement. IMRT plans yielded significantly better doses to the organs-at-risk, and DIBH plans yielded significantly lower liver, heart, and lung Dmean and spinal cord Dmax with smaller irradiated volumes compared to FB plans. For the mean PQM scores, VMAT-DIBH and SIMRT-DIBH yielded the best scores, whereas 3D plans provided reduced beam monitor unit values. Conclusion Our findings demonstrate that modern RT technologies (DIBH with VMAT or SIMRT) could potentially provide excellent target coverage for gastric MALToma while reducing doses to organs-at-risk. However, the relevance of the most optimal plan considering clinical outcomes should be confirmed further in a larger patient cohort.