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Purpose: To evaluate the intra‐fractional tumor motion in lung stereotactic body radiotherapy (SBRT) with deep inspiration breath‐hold (DIBH), and to investigate the adequacy of the current planning target volume (PTV) margins. Methods: Twenty‐eight lung SBRT patients with DIBH were selected in this study. Among the lesions, twenty‐three were at right or left lower lobe, two at right middle lobe, and three at right or left upper lobe. Post‐treatment gated cone‐beam computed tomography (CBCT) was acquired to quantify the intra‐fractional tumor shift at each treatment. These obtained shifts were then used to calculate the required PTV margin, which was compared with the current applied margin of 5 mm margin in anterior‐posterior (AP) and right‐left (RL) directions and 8 mm in superior‐inferior (SI) direction. The beam delivery time was prolonged with DIBH. The actual beam delivery time with DIBH (Tbeam_DIBH) was compared with the beam delivery time without DIBH (Tbeam_wo_DIBH) for the corresponding SBRT plan. Results: A total of 113 treatments were analyzed. At six treatments (5.3%), the shifts exceeded the tolerance defined by the current PTV margin. The average shifts were 0.0 ± 1.9 mm, 0.1±1.5 mm, and ‐0.5 ± 3.7 mm in AP, RL, and SI directions, respectively. The required PTV margins were determined to be 4.5, 3.9, and 7.4 mm in AP, RL, and SI directions, respectively. The average Tbeam_wo_DIBH and Tbeam_DIBH were 2.4 ± 0.4 min and 3.6 ± 1.5 min, respectively. The average treatment slot for lung SBRT with DIBH was 25.3 ± 7.9 min. Conclusion: Intra‐fractional tumor motion is the predominant source of treatment uncertainties in CBCT‐guided lung SBRT with DIBH. The required PTV margin should be determined based on data specific to each institute, considering different techniques and populations. Our data indicate that our current applied PTV margin is adequate, and it is possible to reduce further in the RL direction. The time increase of Tbeam_DIBH, relative to the treatment slot, is not clinically significant. [ABSTRACT FROM AUTHOR]

Purpose: The use of volumetric modulated arc therapy (VMAT), simultaneous integrated boost (SIB), and hypofractionated regimen requires adequate patient setup accuracy to achieve an optimal outcome. The purpose of this study was to assess the setup accuracy of patients receiving left‐sided breast cancer radiotherapy using deep inspiration breath‐hold technique (DIBH) and surface guided radiotherapy (SGRT) and to calculate the corresponding setup margins. Methods: The patient setup accuracy between and within radiotherapy fractions was measured by comparing the 6DOF shifts made by the SGRT system AlignRT with the shifts made by kV‐CBCT. Three hundred and three radiotherapy fractions of 23 left‐sided breast cancer patients using DIBH and SGRT were used for the analysis. All patients received pre‐treatment DIBH training and visual feedback during DIBH. An analysis of variance (ANOVA) was used to test patient setup differences for statistical significance. The corresponding setup margins were calculated using the van Herk's formula. Results: The intrafractional patient setup accuracy was significantly better than the interfractional setup accuracy (p < 0.001). The setup margin for the combined inter‐ and intrafractional setup error was 4, 6, and 4 mm in the lateral, longitudinal, and vertical directions if based on SGRT alone. The intrafractional error contributed ≤1 mm to the calculated setup margins. Conclusion: With SGRT, excellent intrafractional and acceptable interfractional patient setup accuracy can be achieved for the radiotherapy of left‐sided breast cancer using DIBH and modern radiation techniques. This allows for reducing the frequency of kV‐CBCTs, thereby saving treatment time and radiation exposure. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to investigate, from a dosimetric perspective, whether helical Tomotherapy (HT) during free breathing (FB) can serve as an alternative technique for treating left-sided breast cancer patients who are unable to comply with the deep inspiration breath hold (DIBH) technique. Material and Methods: For this purpose, the CT images of 20 left breast-only cancer patients acquired in both FB and DIBH phases were utilized. The left breast was contoured as the target volume, while the heart, LAD, ipsilateral and contralateral lungs, and contralateral breast were contoured as organs at risk on the CT images obtained in both DIBH and FB. Planning with the volumetric modulated arc therapy (VMAT) technique was performed on the CT scans obtained in the DIBH (VMAT-DIBH), while planning with the HT technique was carried out on the CT scans obtained in the FB (HT-FB). Subsequently, dosimetric comparison of the plans were done in terms of target coverage and preservation of normal tissues. Results: Both techniques achieved the desired target coverage; however, in terms of D2, Vpres values, Conformity Number (CN), and Homogeneity Index (HI), the HT-FB technique was found to be superior. While the mean doses to the heart were similar for both techniques, doses to the LAD and left lung were found to be superior in plans generated with the HT-FB technique. When compared in terms of contralateral breast and right lung protection, VMAT-DIBH technique was found to be significantly superior. Conclusion: The treatment of left breast-only patients with the HT-FB technique has been observed to provide similar heart protection and better LAD and ipsilateral lung protection compared to the VMAT-DIBH technique without compromising target coverage. However, when the HT-FB technique is used, doses to the contralateral lung and contralateral breast should be carefully evaluated.

Purpose: This study explored whether a free-breathing mean heart dose (FB-MHD) of 4 Gy is a reliable dose threshold for selecting left breast cancer patients after modified radical mastectomy suitable for deep inspiration breath-hold (DIBH) and developed anatomical indicators to predict FB-MHD for rapid selection. Materials and methods: Twenty-three patients with left breast cancer treated with DIBH were included to compare FB and DIBH plans. The patients were divided into the high-risk (FB-MHD ≥ 4 Gy) and low-risk (FB-MHD

Cardioprotection is valued in radiotherapy for patients with left-sided breast cancer. Deep inspiration breath-hold (DIBH) technique can achieve cardioprotection well. However, during DIBH, the extent to which the heart enters the radiation field is affected by the movement of the thorax and diaphragm. The aim of this study was to analyze the correlation between the maximum distance of the heart entering the field (maximum heart distance, MHD) and thoracic diameter changes and diaphragmatic descent in left-sided breast cancer patients during DIBH.

Purpose/background: The aim of this study was to evaluate pencil beam scanning (PBS) proton therapy (PT) in deep inspiration breath-hold (DIBH) for mediastinal lymphoma patients, by retrospectively evaluating plan robustness to the clinical target volume (CTV) and organs at risk (OARs) on repeated CT images acquired throughout treatment. Methods: Sixteen mediastinal lymphoma patients treated with PBS-PT in DIBH were included. Treatment plans (TPs) were robustly optimized on the CTV (7 mm/4.5%). Repeated verification CTs (vCT) were acquired during the treatment course, resulting in 52 images for the entire patient cohort. The CTV and OARs were transferred from the planning CT to the vCTs with deformable image registration and the TPs were recalculated on the vCTs. Target coverage and OAR doses at the vCTs were compared to the nominal plan. Deviation in lung volume was also calculated. Results: The TPs demonstrated high robust target coverage throughout treatment with D98%,CTV deviations within 2% for 14 patients and above the desired requirement of 95% for 49/52 vCTs. However, two patients did not achieve a robust dose to CTV due to poor DIBH reproducibility, with D98%,CTV at 78 and 93% respectively, and replanning was performed for one patient. Adequate OAR sparing was achieved for all patients. Total lung volume variation was below 10% for 39/52 vCTs. Conclusion: PBS PT in DIBH is generally a robust technique for treatment of mediastinal lymphomas. However, closely monitoring the DIBH-reproducibility during treatment is important to avoid underdosing CTV and achieve sufficient dose-sparing of the OARs.

Background and purpose: Proton therapy for breast cancer is usually given in free breathing (FB). With the use of deep inspiration breath-hold (DIBH) technique, the location of the heart is displaced inferiorly, away from the internal mammary nodes and, thus, the dose to the heart can potentially be reduced. The aim of this study was to explore the potential benefit of proton therapy in DIBH compared to FB for highly selected patients to reduce exposure of the heart and other organs at risk. We aimed at creating proton plans with delivery times feasible with treatment in DIBH. Material and methods: Sixteen patients with left-sided breast cancer receiving loco-regional proton therapy were included. The FB and DIBH plans were created for each patient using spot-scanning proton therapy with 2–3 fields, robust and single field optimization. For the DIBH plans, minimum monitor unit per spot and spot spacing were increased to reduce treatment delivery time. Results: All plans complied with target coverage constraints. The median mean heart dose was statistically significant reduced from 1.1 to 0.6 Gy relative biological effectiveness (RBE) by applying DIBH. No statistical significant difference was seen for mean dose and V17Gy RBE to the ipsilateral lung. The median treatment delivery time for the DIBH plans was reduced by 27% compared to the FB plans without compromising the plan quality. Interpretation: The median absolute reduction in dose to the heart was limited. Proton treatment in DIBH may only be relevant for a subset of these patients with the largest reduction in heart exposure.

Personalized precision irradiation of patients with left‐sided breast cancer is possible by examining the setup errors of 3‐ and 4‐mm gated window widths for those treated with deep inspiration breath‐hold (DIBH) treatment. An observational study was performed via a retrospective analysis of 250 cone‐beam computed tomography (CBCT) images of 60 left‐breast cancer patients who underwent whole‐breast radiotherapy with the DIBH technique between January 2021 and 2022 at our hospital. Among them, 30 patients had a gated window width of 3 mm, while the remaining 30 had a gated window width of 4 mm; both groups received radiotherapy using DIBH technology. All patients underwent CBCT scans once a week, and the setup errors in the left‐right (x‐axis), inferior‐superior (y‐axis), and anterior‐posterior (z‐axis) directions were recorded. The clinical‐to‐planning target volume (CTV‐PTV) margins of the two gating windows were calculated using established methods. The setup error in the Y direction was 1.69 ± 1.33 mm for the 3‐mm – wide gated window and 2.42 ± 3.02 mm for the 4‐mm – wide gated window. The two groups had statistically significant differences in the overall mean setup error (Dif 0.7, 95% CI 0.15–1.31, t = 2.48, p= 0.014). The Z‐direction setup error was 2.32 ± 2.12 mm for the 3‐mm – wide gated window and 3.15 ± 3.34 mm for the 4‐mm – wide gated window. The overall mean setup error was statistically significant between the two groups (Dif 0.8, 95% CI 0.13–1.53, t= 2.34, p = 0.020). There was no significant difference in the X‐direction setup error (p > 0.05). Therefore, the CTV‐PTV margin values for a 3‐mm gated window width in the X, Y, and Z directions are 5.51, 5.15, and 7.28 mm, respectively; those for a 4‐mm gated window width in the X, Y, and Z directions are 5.52, 8.16, and 10.21 mm, respectively. The setup errors of the 3‐mm – wide gating window are smaller than those of the 4‐mm – wide gating window in the three dimensions. Therefore, when the patient's respiratory gating window width is reduced, the margin values of CTV‐PTV can be reduced to increase the distance between the PTV and the organs at risk (OARs), which ensures adequate space for the dose to decrease, resulting in lower dose exposure to the OARs (heart, lungs, etc.), thus sparing the OARs from further damage. However, some patients with poor pulmonary function or unstable breathing amplitudes must be treated with a slightly larger gating window. Therefore, this study lays a theoretical basis for personalized precision radiotherapy, which can save time and reduce manpower in the delivery of clinical treatment to a certain extent. Another potential benefit of this work is to bring awareness to the potential implications of a slightly larger gating window during treatment without considering the resulting dosimetric impact. [ABSTRACT FROM AUTHOR]

Objective: To explore the advantages of dosimetry and the treatment efficiency of tangent-arc technology in deep inspiration breath-hold radiotherapy for breast cancer. Methods: Forty patients with left-sided breast cancer who were treated in our hospital from May 2020 to June 2021 were randomly selected and divided into two groups. The first group's plan was a continuous semi-arc that started at 145° (± 5°) and stopped at 325° (± 5°). The other group's plan, defined as the tangent-arc plan, had two arcs: the first arc started at 145° (± 5°) and stopped at 85° (± 5°), and the second arc started at 25° (± 5°) and stopped at 325° (± 5°). We compared the target dose, dose in organs at risk (OARs), and treatment time between the two groups. Results: The target dose was similar between the continuous semiarc and tangent-arc groups. The V5 of the right lung was significantly different between the two groups (Dif 5.52, 95% confidence interval 1.92-9.13, t=3.10, P=0.004), with the patients in the continuous semi-arc and tangent-arc groups having lung V5 values of (9.16 ± 1.62)%, and (3.64 ± 0.73)%, respectively. The maximum dose to the spinal cord was (1835.88 ± 222.17) cGy in the continuous semi-arc group and (599.42 ± 153.91) cGy in the tangent-arc group, yielding a significant difference between the two groups (Dif 1236.46, 95% confidence interval 689.32-1783.6, t=4.57, P<0.001). The treatment times was (311.70 ± 60.45) s for patients in the continuous semi-arc group and (254.66 ± 40.73) s for patients in the tangent-arc group, and there was a significant difference in the mean number of treatment times between the two groups (Dif 57.04, 95% confidence interval 24.05-90.03, t=3.5, P=0.001). Conclusion: Both the continuous semi-arc and tangent-arc plans met the clinical prescription dose requirements. The OARs received less radiation with the tangent-arc plan than the continuous semi-arc plan, especially for the lung measured as V5) and the spinal cord (measured as the maximum dose). Tangentarc plan took significantly less time than the continuous semi-arc, which can greatly improve treatment efficiency. Therefore, tangent-arc plans are superior continuous semi-arc plans for all cases. [ABSTRACT FROM AUTHOR]

This study aimed to identify high-risk factors for high cardiac radiation exposure, based on anatomical measurements taken from planning CT images of patients with left-sided breast cancer who underwent breast-conserving surgery and received radiotherapy. We retrospectively analyzed 45 patients with left-sided breast cancer who underwent whole-breast radiotherapy, either under free breathing (27/45) or deep inspiratory breath-holding (DIBH) (18/45), after breast-conserving surgery. Six anatomical parameters were measured from planning CT images, including treatment planning target volume (PTV), cardiopulmonary volume ratio (CVR), maximum cardiac margin distance, the relative distance between inferior boundaries of heart and PTV (DBIB(H2P)), axial cardiac contact distance, and para-sagittal cardiac contact distance (CCDps). Multiple linear regression analysis was performed using SPSS software to explore the correlation between the six parameters, body mass index (BMI), and the mean heart dose (MHD). Receiver operating characteristic (ROC) analysis was performed to evaluate the predictive power of the selected predictor of cardiac dose exposure. Significant correlations were observed between the MHD of patients and the CVR, DBIB(H2P), and CCDps parameters. Among them, the CVR was the most important predictor of cardiac dose exposure, with an area under the curve of 0.915 and a cut-off value of 0.17. The study results indicated that CVR, DBIB(H2P), and CCDps are the primary parameters associated with the risk of cardiac dose exposure, with CVR being the most significant predictor. Further prospective studies are required to determine whether these parameters can be used to identify patients who would benefit from the DIBH technique. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effectiveness of a new patient-setup procedure using surface-guided imaging during the coronavirus disease 2019 (COVID-19) pandemic for left-sided whole-breast irradiation with deep inspiration breath-hold. Two setup procedures were compared regarding patient positioning accuracy for the first 22 patients. The first was a traditional setup (T-setup) procedure that used a surface-guided system after patient setup with traditional skin marks and lasers. The second procedure involved a new setup (N-setup) that used only a surface-guided system. The positioning accuracy of the remaining 23 patients was assessed using a setup that combined marker reduction and the N-setup procedure. No significant difference was observed in positioning accuracy between the two setups. The positioning accuracy of the marker-reduction setup was within 3 mm in all directions. The N-setup procedure may be a useful strategy for preventing infection during or after the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Breast cancer has been the leading cause of morbidity among women for many years. In 2020, it accounted for nearly 24% of all registered cancers in the female Polish population. Key risk factors for breast cancer include female gender, age, genetic factors, and factors related to the levels of sex hormones. However, there is a need for more precise research taking into account the impact of certain chemical substances, especially medications. A primary symptom of breast cancer is a lump in the breast; therefore, self-examination and preventive screenings such as mammography and breast ultrasound are crucial. Breast cancer cells exhibit distinctive molecular markers on their surface, resulting in the categorization of the disease into biological subtypes, which continue to evolve with advancing knowledge. In the realm of surgical treatment, efforts persist to limit axillary lymph node dissection (ALND) and prevent the occurrence and treatment of lymphedema. In the field of surgical treatment, there is still a pursuit to limit the performance of axillary lymph node dissection (ALND) and prevent the occurrence of lymphedema, which could be treated by utilizing microsurgical procedures e.g. lymphovenous anastomosis (LVA). Treatment for breast cancer includes, in addition to standard chemotherapy and hormone therapy, the use of immunotherapy. The latest drugs are immunconjugates, which are a combination of a monoclonal antibody with a cytostatic agent. Promising outcomes are linked to treatments focused on identified genetic mutations in cancer cells. Ongoing studies contribute to the discovery of drug targets, enabling the introduction of novel molecularly targeted therapies. These approaches facilitate achieving longer disease stabilization even in patients with metastases. Radiation therapy remains a crucial method for treating breast cancer. Due to precise planning, based on increasingly advanced imaging methods and the application of deep inspiration breath-hold (DIBH) techniques, adverse effects of radiation are limited. [ABSTRACT FROM AUTHOR]

Background and purpose: Real-time treatment monitoring with the electronic portal imaging device (EPID) can conceptually provide a more accurate assessment of the quality of deep inspiration breath-hold (DIBH) and patient movement during tangential breast radiotherapy (RT). A system was developed to measure two geometrical parameters, the lung depth (LD) and the irradiated width (named here skin distance, SD), along three user-selected lines in MV EPID images of breast tangents. The purpose of this study was to test the system during tangential breast RT with DIBH. Materials and methods: Measurements of LDs and SDs were carried out in real time. DIBH was guided with a commercial system using a marker block. Results from 17 patients were assessed. Mean midline LDs, , per tangent were compared to the planned mLDs; differences between the largest and smallest observed () per tangent were calculated. Results: For 56% (162/288) of the tangents tested, were outside the tolerance window. All but one patient had at least one fraction showing this behaviour. The largest difference found between an and its planned mLD was −16.9 mm. The accuracy of patient positioning and the quality of marker-block-based DIBH guidance contributed to the differences. Fractions with patient position verification using a single EPID image taken before treatment showed a lower rate (34%), suggesting reassessment of setup procedures. Conclusions: Real-time treatment monitoring of the internal anatomy during DIBH delivery of tangential breast RT is feasible and useful. The new system requires no additional radiation for the patient.

Purpose: The purpose of this study was to compare two techniques of irradiation of left-sided breast cancer patients who underwent breast-conserving surgery, three-dimensional conformal radiotherapy technique (3D-CRT) and volumetric modulated arc therapy (VMAT), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim of the study was estimation of the projected risk of radiation-induced secondary cancer for both radiotherapy techniques. Materials and methods: For 25 patients who underwent CT simulation in deep inspiration breath-hold (DIBH), three treatment plans were generated: one using a three-dimensional conformal radiotherapy technique and two using volumetric modulated arc therapy. First VMAT-DIBH geometry consisted of three partial arcs (ARC-DIBH 3A) and second consisted of four partial arcs (ARC-DIBH 4A). Cumulative dose–volume histograms (DVHs) were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], ipsilateral and contralateral lung [IL, CL], and contralateral breast [CB]). Normal tissue complication probabilities (NTCPs) and organ equivalent doses (OEDs) were calculated using the differential DVHs. Excess absolute risks (EARs) for second cancers were estimated using Schneider's full mechanistic dose–response model. Results: All plans fulfilled the criterium for PTV V95% ≥ 95%. The PTV coverage, homogeneity, and conformity indices were significantly better for VMAT-DIBH. VMAT showed a significantly increased mean dose and V5Gy for all OARs, but reduced LAD Dmax by 15 Gy. For IL, CL, and CB, the 3D-CRT DIBH method achieved the lowest values of EAR: 28.38 per 10,000 PYs, 2.55 per 10,000 PYs, and 4.48 per 10,000 PYs (p < 0.001), compared to 40.29 per 10,000 PYs, 15.62 per 10,000 PYs, and 23.44 per 10,000 PYs for ARC-DIBH 3A plans and 41.12 per 10,000 PYs, 15.59 per 10,000 PYs, and 22.73 per 10,000 PYs for ARC-DIBH 4A plans. Both techniques provided negligibly low NTCPs for all OARs. Conclusion: The study shows that VMAT-DIBH provides better OAR sparing against high doses. However, the large low-dose-bath (≤ 5 Gy) is still a concern due to the fact that a larger volume of normal tissues exposed to lower doses may increase a radiation-induced risk of secondary cancer. [ABSTRACT FROM AUTHOR]

Background and purpose: In lung Stereotactic Body Radiotherapy (SBRT) respiratory management is used to reduce target motion due to respiration. This study aimed (1) to estimate intrafraction shifts through a Cone Beam Computed Tomography (CBCT) acquired during the first treatment arc when deep inspiration breath-hold (DIBH) was performed using spirometry-based (SB) or surface-guidance (SG) systems and (2) to analyze the obtained results depending on lesion localization. Material and methods: A sample of 157 patients with 243 lesions was analyzed. A total of 860 and 410 fractions were treated using SB and SG. Averaged intrafraction shifts were estimated by the offsets obtained when registering a CBCT acquired during the first treatment arc with the planning CT. Offsets were recorded in superior-inferior (SI), left–right (LR) and anterior-posterior (AP). Significance tests were applied to account for differences in average offsets and variances between DIBH systems. Systematic and random errors were computed. Results: Average offset moduli were 2.4 ± 2.2 mm and 3.5 ± 2.6 mm for SB and SG treatments (p 0.3). However, variances were statistically smaller for SB than for SG (p

Background and purpose: Radiotherapy (RT) is an important part in the treatment of gastric lymphomas and the prognosis after radiotherapy is very good with a good chance of long-term survival, so prevention of long-term adverse effects is important. In patients with gastric lymphomas cardiac late effects are of most concern. The aim of this study was to assess if the dose to the heart could be reduced with deep inspiration breath-hold (DIBH) without compromising the dose to the target or increasing the risk of other late effects. Methods and patients: Fifteen patients with gastric lymphoma were included. RT plans were made using DIBH and Free breathing (FB) scans. Clinical target volume (CTV) was the stomach plus 1 cm margin. The heart and surrounding organs at risk (OAR) were contoured. Two sets of plan comparisons were made, one with 1 cm CTV to planning target volume (PTV) margin in both DIBH and FB and one set with an additional 5 mm CTV to PTV margin in cranio-caudal direction with FB. Datasets were analysed with Wilcoxon signed rank test for non-parametric paired data. Results: All patients tolerated the procedures and were treated with volumetric arc therapy technique in DIBH. Target coverage was kept equal between FB and DIBH, while a statistically significant reduction of the estimated does to the heart was seen with DIBH. Median mean heart dose was reduced from 7.1 Gy (5.7–12) to a median of 3.2 Gy (1.2–7.0) and heart V20 from a median of 54 (17–106) cm3 to 15. (0.0–78) cm3. The estimated mean doses to the liver, duodenum, pancreas and spinal cord were at the same level. Conclusion: This clinical trial of RT with DIBH for gastric lymphomas showed that the heart dose could be reduced without compromising PTV coverage. The doses to abdominal OARs were similar with FB and DIBH.

Abstract Background This study aimed to investigate preoperative spirometry and BMI as early predictors of the mean heart and lung dose (MHD, MLD) in deep inspiration breath-hold (DIBH) radiotherapy. Methods Left-sided breast cancer patients underwent breast-conserving surgery followed by DIBH radiotherapy enrolled. Patients who were not available for preoperative spirometry were excluded. One hundred eligible patients were performed free-breathing (FB-) CT and DIBH-CT for plan comparison. We completed the correlative and multivariate analysis to develop the linear regression models for dose prediction. The residuals were calculated to explore the unpreferable subgroups and compare the prediction accuracy. Results Among the parameters, vital capacity (VC) and BMI showed the strongest negative correlation with MHD (r = − 0.33) and MLD (r = − 0.34), respectively. They were also significant in multivariate analysis (P

Purpose: To investigate the possibility to be able to offer left sided breast cancer patients, not suitable for DIBH, an organ at risk saving treatment. Materials and Methods: Twenty patients receiving radiotherapy for left breast cancer in DIBH were enrolled in the study. Planning CT scans were acquired in the same supine treatment position in FB and DIBH. 3DCRT_DIBH plans were designed and optimized using two parallel opposed tangent beams (with some additional segments) for the breast and chest wall and anterior-posterior fields for regional lymph nodes irradiation. Additionally, FB helical tomotherapy plans were optimized to minimize heart and lung dose. All forty plans were optimized with at least 95% of the total CTV covered by the 95% of prescribed dose of 50 Gy in 25 fractions. Results: HT_FB plans showed significantly better dose homogeneity and conformity compared to the 3DCRT_DIBH specially for regional nodal irradiation. The heart mean dose was almost comparable in 3DCRT_DIBH and HT_FB while the volume (%) of the heart receiving 25 Gy had a statistically significant reduction from 7.90 ± 3.33 in 3DCRT_DIBH to 0.88 ± 0.66 in HT_FB. HT_FB was also more effective in left descending artery (LAD) mean dose reduction about 100% from 30.83 ± 9.2 Gy to 9.7 ± 3.1. The ipsilateral lung volume receiving 20 Gy has a further reduction of 43 % in HT_FB compared with 3DCRT_DIBH. For low dose comparison, 3DCRT_DIBH was superior for contralateral organ sparing compared to the HT_FB due to the limited angle for dose delivery. Conclusion: For patients who cannot be a candidate for DIBH for any reason, HT in free breathing may be a good alternative and provides heart and ipsilateral lung dose sparing, however with the cost of increased dose to contralateral breast and lung.

Background and purpose: Deep inspiration breath-hold (DIBH) is a technique that is widely utilised to spare the heart and lungs during breast radiotherapy. In this study, a method was developed to validate directly the intrafraction accuracy of DIBH during breast volumetric modulated arc therapy (VMAT) via internal chest wall (CW) monitoring. Materials and methods: In-house software was developed to automatically extract and compare the treatment position of the CW in cine-mode electronic portal image device (EPID) images with the planned CW position in digitally reconstructed radiographs (DRR) for breast VMAT treatments. Feasibility of this method was established by evaluating the percentage of total dose delivered to the target volume when the CW was sufficiently visible for monitoring. Geometric accuracy of the approach was quantified by applying known displacements to an anthropomorphic thorax phantom. The software was used to evaluate (offline) the geometric treatment accuracy for ten patients treated using real-time position management (RPM)-guided DIBH. Results: The CW could be monitored within the tangential sub-arcs which delivered a median 89% (range 73% to 97%) of the dose to target volume. The phantom measurements showed a geometric accuracy within 1 mm, with visual inspection showing good agreement between the software-derived and user-determined CW positions. For the RPM-guided DIBH treatments, the CW was found to be within ±5 mm of the planned position in 97% of EPID frames in which the CW was visible. Conclusion: An intrafraction monitoring method with sub-millimetre accuracy was successfully developed to validate target positioning during breast VMAT DIBH.

Purpose: To evaluate normal lung and heart tissue doses for treatment of left-sided breast cancer in deep inspiration breath-hold (DIBH) and free breathing (FB) as a function of breast size and diaphragm displacement using 4D-XCAT digital phantom in a simulation study. Materials and Methods: 4D-XCAT digital phantom was used to create 36 left-sided breast cancer digital phantom datasets with different breast height (BH) of 40, 50, and 60 mm, breast length (BL) of 16, 17, and 18 mm, and diaphragm excursion of 20, 25, 30, and 35 mm. For each dataset, DIBH and FB treatment plans were prepared using planning computerized radiotherapy-three dimensional (PCRT-3D) treatment planning system (TPS) with superposition computational algorithm. Dose differences in DIBH and FB plans were assessed in terms of mean lung dose (MLD), the lung volume receiving ≤20 Gy (V20), normal tissue complication probability (NTCP) of the lung, mean heart dose (MHD), and the heart volume receiving ≤30 (V30). Results: DIBH reduced mean dose and V20 and NTCP of the lung in all cases, by up to 4.37 Gy, 7.62%, and 18.95%. Mean dose and V30 of the heart were also significantly reduced by 5.02 Gy and 8.23%. Conclusions: The use of DIBH for left-sided breast cancer radiotherapy offers excellent possibilities for sparing critical normal tissue without compromising radiation dose to the target. [ABSTRACT FROM AUTHOR]

This clinical study aimed to evaluate lung cancer patients' ability to perform deep inspiration breath‐hold (DIBH) during CT simulation and throughout the treatment course of stereotactic body radiation therapy (SBRT). In addition, target sizes, organ at risk (OAR) sizes, and doses to the respective volumes in filter‐free volumetric‐modulated arc therapy plans performed under free‐breathing (FB) and DIBH conditions were evaluated. Twenty‐one patients with peripheral lesions were included, of which 13 were eligible for SBRT. All patients underwent training for breath‐hold during CT, and if they complied with the requirements, two CT scans were obtained: CT scan in DIBH and a four‐dimensional CT scan in FB. The treatment plans in FB and DIBH were generated, and the dose parameters and volume sizes were compared. The endpoints for evaluation were patient compliance, target dose coverage, and doses to the OARs. This clinical study showed high patient DIBH compliance during both CT simulation and treatment for patients with lung cancer. A significant reduction in target volumes was achieved with SBRT in DIBH, in addition to significantly decreased doses to the heart, chest wall, and lungs. DIBH in SBRT of lung lesions is feasible, and a routine to manage intra‐fractional deviation should be established upon implementation. [ABSTRACT FROM AUTHOR]

Purpose/Objective: Deep Inspiration Breath Hold (DIBH) is now considered as the standard of care for many breast cancer patients. However, there are still uncertainties about the dose given to the heart, and it is unknown if patients may improve voluntary DIBH depth by gaining experience during treatment. In this study, we will examine the interfractional three-dimensional (3D) heart displacement throughout voluntary DIBH (vDIBH) radiotherapy by means of daily cone-beam computed tomography (CBCT). Material and methods: Two hundred twenty-five unique CBCTs from 15 patients treated in 15 fractions were analyzed. During CBCT, a vDIBH was conducted without any visual feedback. Patients performed their DIBH freely after receiving explanations and training. After daily CBCT matching to the chest wall (CW), surface-guided radiation therapy (SGRT) tracked DIBH depth to ensure that the CW position was the same as the daily acquired CBCT. The CBCTs were retrospectively registered to the DIBH planning-CT to calculate daily changes in heart displacement relative to the CW. Results: The mean displacement of the heart during DIBH treatment relative to the DIBH planning-CT was as follows: 1.1 mm to the right, interquartile range (IQR) 8.0; 0.5 mm superiorly, IQR 4.8; and 0 mm posteriorly, IQR 6.4. The Spearman correlation coefficients (rs) were -0.15 (p=0.025), 0.04 (p=0.549), and 0.03 (p=0.612) for the X, Y, and Z directions, respectively. The differences in median heart displacement were significant: Friedmann rank sum test p=0.031 and pairwise comparison using the Wilcoxon rank-sum test were p=0.008 for X and Y; p=0.33 for X and Z; and p=0.07 for Y and Z. The total median heart motion was dtot median= 7.26 mm, IQR= 6.86 mm. Conclusion: During DIBH, cliniciansmust be aware of the wide range of intraand inter-individual heart position variations. The inter-individual heterogeneity shown in our study should be investigated further in order to avoid unexpected cardiac overexposure and to develop a more accurate heart dose-volume model. [ABSTRACT FROM AUTHOR]

Background: The aim of our study is to determine whether deep inspiration breath hold (DIBH) is effective for reducing exposure of the heart, left coronary artery (LAD) and both lungs in right breast radiotherapy. Materials and methods: We have analyzed 10 consecutive patients with right-sided breast cancer (BC), simulated during free breathing (FB) and in DIBH modality. For all patients we contoured breast PTV and organs at risk (right and left lungs, heart, LAD) on both CT scans (FB and DIBH). Finally, 5 patients were treated with IMRT and 5 with VMAT techniques. Results: All patients were able to end the treatments in DIBH modalities regardless of the longer treatment time in comparison to FB. The maximum and mean dose to the heart are lower in the DIBH modality. The mean values of the heart mean dose were 1.76 Gy in DIBH and 2.19 Gy in FB. The mean heart maximum dose in DIBH and FB were, respectively, 9.3 Gy and 11 Gy. Likewise, the maximum dose to the LAD is lower in DIBH; 2.57 Gy versus 3.56 Gy in FB. Noteworthy, 3 patients with hepatomegaly treated with the DIBH technique showed a higher ipsilateral lung dose than FB, but a decrease of liver dose. Conclusion: We report that the use of DIBH for right-sided BC allows the dose to the heart, LAD and to the liver to be reduced in case of hepatomegaly. This technique is well tolerated by patients, when adequately trained, and could be considered effective even in right sided BC. [ABSTRACT FROM AUTHOR]

Purpose/ObjectiveDeep Inspiration Breath Hold (DIBH) is now considered as the standard of care for many breast cancer patients. However, there are still uncertainties about the dose given to the heart, and it is unknown if patients may improve voluntary DIBH depth by gaining experience during treatment. In this study, we will examine the interfractional three-dimensional (3D) heart displacement throughout voluntary DIBH (vDIBH) radiotherapy by means of daily cone-beam computed tomography (CBCT).Material and methodsTwo hundred twenty-five unique CBCTs from 15 patients treated in 15 fractions were analyzed. During CBCT, a vDIBH was conducted without any visual feedback. Patients performed their DIBH freely after receiving explanations and training. After daily CBCT matching to the chest wall (CW), surface-guided radiation therapy (SGRT) tracked DIBH depth to ensure that the CW position was the same as the daily acquired CBCT. The CBCTs were retrospectively registered to the DIBH planning-CT to calculate daily changes in heart displacement relative to the CW.ResultsThe mean displacement of the heart during DIBH treatment relative to the DIBH planning-CT was as follows: 1.1 mm to the right, interquartile range (IQR) 8.0; 0.5 mm superiorly, IQR 4.8; and 0 mm posteriorly, IQR 6.4. The Spearman correlation coefficients (rs) were -0.15 (p=0.025), 0.04 (p=0.549), and 0.03 (p=0.612) for the X, Y, and Z directions, respectively. The differences in median heart displacement were significant: Friedmann rank sum test p=0.031 and pairwise comparison using the Wilcoxon rank-sum test were p=0.008 for X and Y; p=0.33 for X and Z; and p=0.07 for Y and Z. The total median heart motion was δtot median= 7.26 mm, IQR= 6.86 mm.ConclusionDuring DIBH, clinicians must be aware of the wide range of intra- and inter-individual heart position variations. The inter-individual heterogeneity shown in our study should be investigated further in order to avoid unexpected cardiac overexposure and to develop a more accurate heart dose-volume model.

Abstract Background To improve split-VMAT technique by optimizing treatment delivery time for deep-inspiration breath hold (DIBH) radiotherapy in left-sided breast cancer patients, when automatic beam-interruption devices are not available. Methods Ten consecutive patients were treated with an eight partial arcs (8paVMAT) plan, standard of care in our center. A four partial arcs (4paVMAT) plan was also created and actual LINAC outputs were measured, to evaluate whether there was a dosimetric difference between both techniques and potential impact on the delivered dose. Subsequently, ten other patients were consecutively treated with a 4paVMAT plan to compare the actual treatment delivery time between both techniques. The prescribed dose was 40.05 Gy/15 fractions on the PTV breast (breast or thoracic wall), lymph nodes (LN) and intramammary lymph node chain (IMN). Treatment delivery time, PTVs coverage, conformity index (CI), organs at risk (OAR) dose, monitor units (MU), and gamma index were compared. Results Both split-VMAT techniques resulted in similar dose coverage for the PTV Breast and LN, and similar CI. For PTV IMN we observed a 5% increased coverage for the volume receiving ≥ 36 Gy with 4paVMAT, with an identical volume receiving ≥ 32 Gy. There was no difference for the OAR sparing, with the exception of the contralateral organs: there was a 0.6 Gy decrease for contralateral breast mean (p ≤ 0.01) and 1% decrease for the volume of right lung receiving ≥ 5 Gy (p = 0.024). Overall, these results indicate a modest clinical benefit of using 4paVMAT in comparison to 8paVMAT. An increase in the number of MU per arc was observed for the 4paVMAT technique, as expected, while the total number of MU remained comparable for both techniques. All the plans were measured with the Delta4 phantom and passed the gamma index criteria with no significant differences. Finally, the main difference was seen for the treatment delivery time: there was a significant decrease from 8.9 to 5.4 min for the 4paVMAT plans (p

To investigate PET/CT registration and quantification accuracy of thoracic lesions of a single 30-second deep-inspiration breath-hold (DIBH) technique with a total-body PET (TB-PET) scanner, and compared with free-breathing (FB) PET/CT. 137 of the 145 prospectively enrolled patients finished a routine FB-300 s PET/CT exam and a 30-second DIBH TB-PET with chest to pelvis low dose CT. The total-body FB-300 s, FB-30 s, and DIBH-30 s PET images were reconstructed. Quantitative assessment (SUV max and SUV mean of lung and other organs), PET/CT registration assessment and lesion analysis (SUV max , SUV peak , SUV mean and tumor-background ratio) were compared with Wilcoxon signed-rank tests. The SUV max and SUV mean of the lung with DIBH-30 s were significantly lower than those with FB. The distances of the liver dome between PET and CT were significantly smaller with DIBH-30 s than with FB. 195 assessable lesions in 106 patients were included, and the detection sensitivity was 97.9 % and 99.0 % in FB-300 s, and DIBH-30 s, respectively. For both small co-identified lesions (n = 86) and larger co-identified lesions with a diameter ≥ 1 cm (n = 91), the lesion SUVs were significantly greater with DIBH-30 s than with FB-300 s. Regarding lesion location, the differences of the SUVs for the lesions in the lower thorax area (n = 97, p < 0.001) were significant between DIBH-30 s and FB-300 s, while these differences were not statistically significant in the upper thorax (n = 80, p > 0.05). The lesion tumor-to-surrounding-background ratio (TsBR) was significantly increased, both in the upper and lower thorax. The TB DIBH PET/CT technique is feasible in clinical practice. It reduces the background lung uptake and achieves better registration and lesion quantification, especially in the lower thorax. [ABSTRACT FROM AUTHOR]

Studying setup accuracy in breast cancer patients with axillary lymph node inclusion in deep inspiration breath-hold (DIBH) after patient setup with surface-guided radiotherapy (SGRT) and image-guided radiotherapy (IGRT). Breast cancer patients (N = 51) were treated (50 Gy in 25 fractions) with axillary lymph nodes within the planning target volume (PTV). Patient setup was initiated with tattoos and lasers, and further adjusted with SGRT. The DIBH guidance was based on SGRT. Orthogonal and/or tangential imaging was analyzed for residual position errors of bony landmarks, the breath-hold level (BHL), the skin outline, and the heart; and setup margins were calculated for the PTV. The calculated PTV margins were 4.3 to 6.3 and 2.8 to 4.6 mm before and after orthogonal imaging, respectively. The residual errors of the heart were 3.6 ± 2.2 mm and 2.5 ± 2.4 mm before and 3.0 ± 2.5 and 2.9 ± 2.3 mm after orthogonal imaging in the combined anterior-posterior/lateral and the cranio-caudal directions, respectively, in tangential images. The humeral head did not benefit from daily IGRT, but SGRT guided it to the correct location. We presented a slightly complicated but highly accurate workflow for DIBH treatments. The residual position errors after both SGRT and IGRT were excellent compared to previous literature. With well-planned SGRT, IGRT brings only slight improvements to systematic accuracy. However, with the calculated PTV margins and the number of outliers, imaging cannot be omitted despite SGRT, unless the PTV margins are re-evaluated. [ABSTRACT FROM AUTHOR]

Introduction - Radiotherapy (RT) is a therapeutic approach for the treatment of left breast cancer. However, different breathing techniques free breathing (FB) and deep inspiration breath-hold (DIBH) can be used. Objectives - To identify which of the breathing techniques, DIBH or FB, has obtained better irradiation of the planning target volume (PTV) and a lower dose at the organs at risk (OAR). Check if the DIBH technique allows a dose reduction in the left ventricle. Method - Twenty female patients with pathology in the left breast were selected. In computed tomography, the contours of PTV and OAR were made. We obtained dosimetric data for each patient, with each of the two types of breathing techniques. Dosimetric data for all patients were compared and for both respiratory techniques. Results - The DIBH technique reduced the mean dose (Dmean) and V20% in the left lung, only being higher in four patients. In the left ventricle, there was a decrease in Dmean and V30% in all patients. The spinal cord in either DIBH or FB did not reach the reference limit, however, there was an improvement when using DIBH. Conclusions - The DIBH technique presents lower doses in the organs at risk, improvements in PTV dose coverage, as well as conformity, homogeneity, and quality indexes when compared to the FB technique. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to quantify errors by using a cine electronic portal imaging device (cine EPID) during deep inspiration breath-hold (DIBH) for left-sided breast cancer and to estimate the planning target volume (PTV) by variance component analysis. Methods This study included 25 consecutive left-sided breast cancer patients treated with whole-breast irradiation (WBI) using DIBH. Breath-holding was performed while monitoring abdominal anterior–posterior (AP) motion using the Real-time Position Management (RPM) system. Cine EPID was used to evaluate the chest wall displacements in patients. Cine EPID images of the patients (309,609 frames) were analyzed to detect the edges of the chest wall using a Canny filter. The errors that occurred during DIBH included differences between the chest wall position detected by digitally reconstructed radiographs and that of all cine EPID images. The inter-patient, inter-fraction, and intra-fractional standard deviations (SDs) in the DIBH were calculated, and the PTV margin was estimated by variance component analysis. Results The median patient age was 55 (35–79) years, and the mean irradiation time was 20.4 ± 1.7 s. The abdominal AP motion was 1.36 ± 0.94 (0.14–5.28) mm. The overall mean of the errors was 0.30 mm (95% confidence interval: − 0.05–0.65). The inter-patient, inter-fraction, and intra-fractional SDs in the DIBH were 0.82 mm, 1.19 mm, and 1.63 mm, respectively, and the PTV margin was calculated as 3.59 mm. Conclusions Errors during DIBH for breast radiotherapy were monitored using EPID images and appropriate PTV margins were estimated by variance component analysis.

Background: Published treatment technique comparisons for postoperative left-sided whole breast irradiation (WBI) with deep-inspiration breath-hold (DIBH) are scarce, small, and inconclusive. In this study, fully automated multi-criterial plan optimization, generating a single high-quality, Pareto-optimal plan per patient and treatment technique, was used to compare for a large patient cohort 1) intensity modulated radiotherapy (IMRT) with two tangential fields and 2) volumetric modulated arc therapy (VMAT) with two small tangential subarcs. Materials and methods: Forty-eight randomly selected patients recently treated with DIBH and 16 × 2.66 Gy were included. The optimizer was configured for the clinical planning protocol. Comparisons between IMRT and VMAT included dosimetric plan parameters, estimated excess relative risks (ERR) for toxicities, delivery times, MUs, and deliverability accuracy at a linac. Results: The automatically generated IMRT and VMAT plans applied in this study were similar or higher in quality than the manually generated clinical plans. For equal PTVin V95% (98.4 ± 0.9%), VMAT had significant advantages compared to IMRT regarding breast dose homogeneity and doses in heart and ipsilateral lung, at the cost of some minor deteriorations for contralateral breast (few cases with larger deteriorations) and lung. Conformality improved from 1.38 to 1.18 (p < 0.001). With VMAT, ERR for major coronary events and ipsilateral lung tumors were reduced by 3% (range: −1–12%) and 16% (range: −3–38%), respectively. MUs and delivery times were higher for VMAT. There were no statistical differences in γ passing rates. Conclusion: For WBI in conservative therapy of left-sided breast patients treated with DIBH, VMAT with two tangential subarcs was generally dosimetrically superior to IMRT with two tangential static fields. Results need confirmation by robustness analyses. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate preoperative spirometry and BMI as early predictors of the mean heart and lung dose (MHD, MLD) in deep inspiration breath-hold (DIBH) radiotherapy.Methods: Left-sided breast cancer patients underwent breast-conserving surgery followed by DIBH radiotherapy enrolled. Patients who were not available for preoperative spirometry were excluded. One hundred eligible patients were performed free-breathing (FB-) CT and DIBH-CT for plan comparison. We completed the correlative and multivariate analysis to develop the linear regression models for dose prediction. The residuals were calculated to explore the unpreferable subgroups and compare the prediction accuracy.Results: Among the parameters, vital capacity (VC) and BMI showed the strongest negative correlation with MHD (r = - 0.33) and MLD (r = - 0.34), respectively. They were also significant in multivariate analysis (P < 0.001). Elderly and less VC were independent predictors of increasing absolute residuals (AR). The VC model showed no significant difference in AR compared to the model using the CT parameter of lung volume in FB (LV-FB): median AR of the LV-FB model vs. the VC model was 0.12 vs. 0.11 Gy (P = 0.79). On the other hand, the median AR of the MLD model was 0.38 Gy, showing no specific subgroups of larger AR.Conclusion: Preoperative spirometry and BMI are significant predictors of MHD and MLD, respectively. Although elderly and low-VC patients may have larger predictive variations, spirometry might be a substitute for LV-FB as a predictor of MHD. [ABSTRACT FROM AUTHOR]

Purpose: Thymic malignancies are the most common anterior mediastinal tumors. Advanced thymic carcinoma treatment relies on chemotherapy and definitive radiation therapy when possible. However, pericardial involvement is problematic for radiation therapy treatment planning owing to significant cardiac radiation exposure. We report the first case of definitive proton beam therapy (PBT) for an advanced thymic carcinoma with pericardial invasion. Materials and Methods: We report the case of a 69-year-old patient treated with definitive radiation therapy for a stage IVB thymic carcinoma with pericardial invasion. Mean doses delivered to critical organs at risk were compared between deep inspiration breath-hold (DIBH) volumetric modulated arc therapy (VMAT) and DIBH-PBT. Results: When compared to DIBH-VMAT, DIBH-PBT reduced the mean doses delivered to the heart by 3.72 Gy (19.0% dose reduction), to the right lung by 5.9 Gy (41.7% dose reduction), to the left lung by 3.63 Gy (19.0% dose reduction), and to the esophagus by 3.57 Gy (21.3% dose reduction). Despite an early mediastinal relapse after 3.0 months, our patient is still alive after a 14-month follow-up, without any radiation-induced cardiac adverse events and is undergoing pembrolizumab-based immunotherapy. Conclusion: Proton beam therapy is an option for definitive irradiation of thymic malignancies invading the pericardium; in this situation, PBT reduces doses to the heart and may help to reduce cardiotoxicity when compared with photon techniques.

We hypothesized that deep inspiration breath-hold (DIBH) and computed-tomography image-guided radiotherapy (CT-IGRT) may be beneficial to decrease dose to organs at risk (OARs), when treating the stomach with radiotherapy for lymphoma. We compared dosimetric parameters of OARs from plans generated using free-breathing (FB) versus DIBH for 10 patients with non-Hodgkin lymphoma involving the stomach treated with involved site radiotherapy. All patients had 4DCT and DIBH scans. Planning was performed with intensity modulated radiotherapy (IMRT) to 30.6 Gy in 17 fractions. Differences in target volume and dosimetric parameters were assessed using a paired two-sided t-test. All heart and left ventricle parameters including mean dose, V30, V20, V10, and V5 were statistically significantly lower with DIBH. For IMRT-FB plans the average mean heart dose was 4.9 Gy compared to 2.6 Gy for the IMRT-DIBH group (p

Purpose: The aim of this study is to investigate, from a dosimetric perspective, whether helical Tomotherapy (HT) during free breathing (FB) can serve as an alternative technique for treating left-sided breast cancer patients who are unable to comply with the deep inspiration breath hold (DIBH) technique., Material and Methods: For this purpose, the CT images of 20 left breast-only cancer patients acquired in both FB and DIBH phases were utilized. The left breast was contoured as the target volume, while the heart, LAD, ipsilateral and contralateral lungs, and contralateral breast were contoured as organs at risk on the CT images obtained in both DIBH and FB. Planning with the volumetric modulated arc therapy (VMAT) technique was performed on the CT scans obtained in the DIBH (VMAT-DIBH), while planning with the HT technique was carried out on the CT scans obtained in the FB (HT-FB). Subsequently, dosimetric comparison of the plans were done in terms of target coverage and preservation of normal tissues., Results: Both techniques achieved the desired target coverage; however, in terms of D2, Vpres values, Conformity Number (CN), and Homogeneity Index (HI), the HT-FB technique was found to be superior. While the mean doses to the heart were similar for both techniques, doses to the LAD and left lung were found to be superior in plans generated with the HT-FB technique. When compared in terms of contralateral breast and right lung protection, VMAT-DIBH technique was found to be significantly superior., Conclusion: The treatment of left breast-only patients with the HT-FB technique has been observed to provide similar heart protection and better LAD and ipsilateral lung protection compared to the VMAT-DIBH technique without compromising target coverage. However, when the HT-FB technique is used, doses to the contralateral lung and contralateral breast should be carefully evaluated., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Purpose: To provide a new insight on a novel safe cardiac radioablation using deep inspiration breath-hold (DIBH) to reduce gastrointestinal dose. Materials and Methods: For treating incessant ventricular tachycardia (VT) originated from left ventricle inferior scar abutting the stomach, a target delineation and treatment planning for cardiac radioablation was performed. With four different computed tomography (CT) scan protocols--DIBH, full expiration breath-hold, four-dimensional (4D) CT without and with abdominal compression, the distances between the target and the stomach were compared. Results: Among the protocols, the CT scan with DIBH showed largest distance between the target and the stomach and selected for the treatment planning. The prescribed dose was 25 Gy in a single fraction, and satisfactory dosimetric parameters were achieved with the DIBH. The patient was successfully treated with the DIBH, and experienced no acute toxicity. Conclusion: To gain the best benefit from cardiac radioablation, understanding the possible toxicity in the adjacent organs is crucial. By moving the heart with thoraco-diaphragmatic movement by DIBH, the target could be physically separated from the stomach. [ABSTRACT FROM AUTHOR]

Abstract Background The addition of regional nodal radiation (RNI) to whole breast irradiation for high risk breast cancer improves metastases free survival and new data suggests it contributes additional benefit to overall survival. Deep inspiration breath hold (DIBH) has been shown to reduce cardiac and pulmonary dose in the context of left-sided disease treated with or without RNI, yet few studies have investigated its utility for right-breast cancer. This study investigates the potential advantages of DIBH in local and locoregional radiotherapy for right-sided breast cancer. Methods Free-breathing (FB) and DIBH computed tomography datasets were obtained from twenty patients who previously underwent radiotherapy for left-sided breast cancer. Ten patients were retrospectively planned for whole right breast only irradiation and ten patients were planned for irradiation to the whole breast plus ipsilateral supra-clavicular (SC) nodes, with and without irradiation of the ipsilateral internal mammary nodes (IMN). Dose-volume metrics for the clinical target volume, lungs, heart, left anterior descending artery, right coronary artery (RCA) and liver were recorded. Differences between FB and DIBH plans were analysed using Wilcoxon signed-rank tests, with P

Abstract Purpose To determine the accuracy of a surface guided radiotherapy (SGRT) system for positioning of breast cancer patients in breath-hold (BH) with respect to cone-beam computed tomography (CBCT). Secondly, to evaluate the thorax position stability during BHs with SGRT, when using an air-volume guidance system. Methods and materials Eighteen left-sided breast cancer patients were monitored with SGRT during CBCT and treatment, both in BH. CBCT scans were matched on the target volume and the patient surface. The setup error differences were evaluated, including with linear regression analysis. The intra-fraction variability and stability of the air-volume guided BHs were determined from SGRT measurements. The variability was determined from the maximum difference between the different BH levels within one treatment fraction. The stability was determined from the difference between the start and end position of each BH. Results SGRT data correlated well with CBCT data. The correlation was stronger for surface-to-CBCT (0.61) than target volume-to-CBCT (0.44) matches. Systematic and random setup error differences were ≤ 2 mm in all directions. The 95% limits of agreement (mean ± 2SD) were 0.1 ± 3.0, 0.6 ± 4.1 and 0.4 ± 3.4 mm in the three orthogonal directions, for the surface-to-CBCT matches. For air-volume guided BHs, the variability detected with SGRT was 2.2, 2.8 and 2.3 mm, and the stability − 1.0, 2.1 and 1.5 mm, in three orthogonal directions. Furthermore, the SGRT system could detect unexpected patient movement, undetectable by the air-volume BH system. Conclusion With SGRT, left-sided breast cancer patients can be positioned and monitored continuously to maintain position errors within 5 mm. Low intra-fraction variability and good stability can be achieved with the air-volume BH system, however, additional patient position information is available with SGRT, that cannot be detected with air-volume BH systems.

Abstract Background The aim of this study was to compare dose-volume histogram (DVH) with dose-mass histogram (DMH) parameters for treatment of left-sided breast cancer in deep inspiration breath-hold (DIBH) and free breathing (FB). Additionally, lung expansion and anatomical factors were analyzed and correlated to dose differences. Methods For 31 patients 3D conformal radiation therapy plans were retrospectively calculated on FB and DIBH CTs in the treatment planning system. The calculated doses, structures and CT data were transferred into MATLAB and DVHs and DMHs were calculated. Mean doses (Dmean), volumes and masses receiving certain doses (Vx, Mx) were determined for the left lung and the heart. Additionally, expansion of the left lung was evaluated using deformable image registration. Differences in DVH and DMH dose parameters between FB and DIBH were statistically analyzed and correlated to lung expansion and anatomical factors. Results DIBH reduced Dmean (DVH) and relative V20 (V20 [%]) of the left lung in all patients, on average by − 19 ± 9% (mean ± standard deviation) and − 24 ± 10%. Dmean (DMH) and M20 [%] were also significantly reduced (− 12 ± 11%, − 16 ± 13%), however 4 patients had higher DMH values in DIBH than in FB. Linear regression showed good correlations between DVH and DMH parameters, e.g. a dosimetric benefit smaller than 8.4% for Dmean (DVH) in DIBH indicated more irradiated lung mass in DIBH than in FB. The mean expansion of the left lung between FB and DIBH was 1.5 ± 2.4 mm (left), 16.0 ± 4.0 mm (anterior) and 12.2 ± 4.6 mm (caudal). No significant correlations were found between expansions and differences in Dmean for the left lung. The heart dose in DIBH was reduced in all patients by 53% (Dmean) and this dosimetric benefit correlated to lung expansion in anterior. Conclusions Treatment of left-sided breast cancer in DIBH reduced dose to the heart and in most cases the lung dose, relative irradiated lung volume and lung mass. A mass related dosimetric benefit in DIBH can be achieved as long as the volume related benefit is about ≥8–9%. The lung expansion (breathing pattern) showed no impact on lung dose, but on heart dose. A stronger chest breathing (anterior expansion) for DIBH seems to be more beneficial than abdominal breathing.

Background: To improve split-VMAT technique by optimizing treatment delivery time for deep-inspiration breath hold (DIBH) radiotherapy in left-sided breast cancer patients, when automatic beam-interruption devices are not available.Methods: Ten consecutive patients were treated with an eight partial arcs (8paVMAT) plan, standard of care in our center. A four partial arcs (4paVMAT) plan was also created and actual LINAC outputs were measured, to evaluate whether there was a dosimetric difference between both techniques and potential impact on the delivered dose. Subsequently, ten other patients were consecutively treated with a 4paVMAT plan to compare the actual treatment delivery time between both techniques. The prescribed dose was 40.05 Gy/15 fractions on the PTV breast (breast or thoracic wall), lymph nodes (LN) and intramammary lymph node chain (IMN). Treatment delivery time, PTVs coverage, conformity index (CI), organs at risk (OAR) dose, monitor units (MU), and gamma index were compared.Results: Both split-VMAT techniques resulted in similar dose coverage for the PTV Breast and LN, and similar CI. For PTV IMN we observed a 5% increased coverage for the volume receiving ≥ 36 Gy with 4paVMAT, with an identical volume receiving ≥ 32 Gy. There was no difference for the OAR sparing, with the exception of the contralateral organs: there was a 0.6 Gy decrease for contralateral breast mean (p ≤ 0.01) and 1% decrease for the volume of right lung receiving ≥ 5 Gy (p = 0.024). Overall, these results indicate a modest clinical benefit of using 4paVMAT in comparison to 8paVMAT. An increase in the number of MU per arc was observed for the 4paVMAT technique, as expected, while the total number of MU remained comparable for both techniques. All the plans were measured with the Delta4 phantom and passed the gamma index criteria with no significant differences. Finally, the main difference was seen for the treatment delivery time: there was a significant decrease from 8.9 to 5.4 min for the 4paVMAT plans (p < .05).Conclusions: This study is mainly of interest for centers who are implementing the DIBH technique without automatic beam-holding devices and who therefore may require to manually switch the beam on and off during breast DIBH treatment. Split-VMAT technique with 4 partial arcs significantly reduces the treatment delivery time compared to 8 partial arcs, without compromising the target coverage and the OAR sparing. The technique decreases the number of breath holds per fraction, resulting in a shorter treatment session. [ABSTRACT FROM AUTHOR]

The purpose of the in silico study was to compare free breathing volumetric modulated arc therapy (VMAT) to standard deep inspiration breath‐hold (DIBH) three‐dimensional conformal radiotherapy (3DCRT) and determine whether the former is a viable option for elderly patients with left‐sided early stage breast cancer. Data from 22 patients with early‐stage left breast carcinoma requiring breast‐only radiation therapy were used for this planning study. The robustness of VMAT plans when using the free breathing method was compared to that of standard 3DCRT plans using the DIBH method. The endpoints for evaluation were the target dose coverage as well as doses to the organs‐at‐risk. The free breathing VMAT plans produced a significantly higher mean dose to the heart and right breast than the DIBH‐3DCRT plans. Free breathing VMAT plans resulted in significantly better target coverage than did 3DCRT using DIBH. The external volume that received more than 40 Gy was significantly smaller in the VMAT plans. Free breathing VMAT is a viable alternative to DIBH 3DCRT in elderly patients with a limited life expectancy and in subjects who are unable to perform DIBH. The choice of treatment should be individualized, and all relevant risks ought to be considered. [ABSTRACT FROM AUTHOR]

Background: This study aimed to quantify errors by using a cine electronic portal imaging device (cine EPID) during deep inspiration breath-hold (DIBH) for left-sided breast cancer and to estimate the planning target volume (PTV) by variance component analysis.Methods: This study included 25 consecutive left-sided breast cancer patients treated with whole-breast irradiation (WBI) using DIBH. Breath-holding was performed while monitoring abdominal anterior-posterior (AP) motion using the Real-time Position Management (RPM) system. Cine EPID was used to evaluate the chest wall displacements in patients. Cine EPID images of the patients (309,609 frames) were analyzed to detect the edges of the chest wall using a Canny filter. The errors that occurred during DIBH included differences between the chest wall position detected by digitally reconstructed radiographs and that of all cine EPID images. The inter-patient, inter-fraction, and intra-fractional standard deviations (SDs) in the DIBH were calculated, and the PTV margin was estimated by variance component analysis.Results: The median patient age was 55 (35-79) years, and the mean irradiation time was 20.4 ± 1.7 s. The abdominal AP motion was 1.36 ± 0.94 (0.14-5.28) mm. The overall mean of the errors was 0.30 mm (95% confidence interval: - 0.05-0.65). The inter-patient, inter-fraction, and intra-fractional SDs in the DIBH were 0.82 mm, 1.19 mm, and 1.63 mm, respectively, and the PTV margin was calculated as 3.59 mm.Conclusions: Errors during DIBH for breast radiotherapy were monitored using EPID images and appropriate PTV margins were estimated by variance component analysis. [ABSTRACT FROM AUTHOR]

Purpose: This study explored whether a free-breathing mean heart dose (FB-MHD) of 4 Gy is a reliable dose threshold for selecting left breast cancer patients after modified radical mastectomy suitable for deep inspiration breath-hold (DIBH) and developed anatomical indicators to predict FB-MHD for rapid selection., Materials and Methods: Twenty-three patients with left breast cancer treated with DIBH were included to compare FB and DIBH plans. The patients were divided into the high-risk (FB-MHD ≥ 4 Gy) and low-risk (FB-MHD < 4 Gy) groups to compare dose difference, normal tissue complication probability (NTCP) and the DIBH benefits. Another 30 patients with FB only were included to analyze the capacity of distinguishing high-risk heart doses patients according to anatomical metrics, such as cardiac-to-chest Euclidean distance (CCED), cardiac-to-chest gap (CCG), and cardiac-to-chest combination (CCC)., Results: All heart doses were significantly lower in patients with DIBH plans than in those with FB plans. Based on FB-MHD of 4 Gy cutoff, the heart dose, NTCP for cardiac death, and benefits from DIBH were significantly higher in the high-risk group than in the low-risk group. The CCED was a valid anatomical indicator with the largest area under the curve (AUC) of 0.83 and maintained 95 % sensitivity and 70 % specificity at the optimal cutoff value of 2.5 mm., Conclusions: An FB-MHD of 4 Gy could be used as an efficient dose threshold for selecting patients suitable for DIBH. The CCED may allow a reliable prediction of FB-MHD in left breast cancer patients at CT simulation., (© 2024 The Authors. Published by Elsevier B.V. on behalf of European Society for Radiotherapy and Oncology.)

Abstract Background Tangent-based intensity modulated radiation therapy (TIMRT) is a common adjuvant radiotherapy strategy for breast cancer patients. This study compared the dosimetric characteristics of tangent-based volumetric modulated arc therapy (TVMAT) and TIMRT for left breast cancer patients during deep inspiration breath-hold (DIBH) and free breathing (FB) techniques. Methods Fourteen patients with left breast cancer after breast-conserving surgery were included. The first arc started at 331.8–353.6 degrees and stopped at 281.8–315.0 degrees. The third arc started at 123.2–149.1 degrees and stopped at 88.0–96.0 degrees. The second and fourth arcs were reverse arcs of first and third arcs. DIBH-TIMRT inversing plans were generated using opposing tangential fields. Wilcoxon signed rank test and Spearman correlation were used to examine the significance of dose difference. Results Compared with FB-TVMAT, the mean heart dose of DIBH-TVMAT plans was reduced from 7.9 Gy to 3.2 Gy (p

Abstract Background Radiotherapy (RT) delivered in deep inspiration breath-hold (DIBH) is a simple technique, in which changes in patient anatomy can significantly reduce the irradiation of the organs at risk (OARs) surrounding the treatment target. DIBH is routinely used in the treatment of some adult patients to diminish the risk of late effects; however, no formalized studies have addressed the potential benefit of DIBH in children. Methods/Design TEDDI is a multicenter, non-randomized, feasibility study. The study investigates the dosimetric benefit of RT delivered in DIBH compared to free breathing (FB) in pediatric patients. Also, the study aims to establish the compliance to DIBH and to determine the accuracy and reproducibility in a pediatric setting. Pediatric patients (aged 5–17 years) with a tumor in the mediastinum or upper abdomen with the possible need of RT will be included in the study. Written informed consent is obligatory. Prior to any treatment, patients will undergo a DIBH training session followed by a diagnostic PET/CT- or CT-staging scan in both DIBH and FB. If the patient proceeds to RT, a RT planning CT scan will be performed in both DIBH and FB and two separate treatment plans will be calculated. The superior treatment plan, i.e. equal target coverage and lowest overall dose to the OARs, will be chosen for treatment. Patient comfort will be assessed daily by questionnaires and by adherence to the respiratory management procedure. Discussion RT in DIBH is expected to diminish irradiation of the OARs surrounding the treatment target and thereby reduce the risk of late effects in childhood cancer survivors. Trial registration The Danish Ethical Committee (H-16035870, approved November 24th 2016, prospectively registered). The Danish Data Protection Agency (2012–58-0004, approved January 1st 2017, prospectively registered). Registered at clinicaltrials.gov (NCT03315546, October 20th 2017, retrospectively registered).

Background: Deep inspiration breath-hold (DIBH) is known as a radiotherapy method for the treatment of patients with left-sided breast cancer. In this method, patient is under exposure only while he/she is at the end of a deep inspiration cycle and holds his/her breath. In this situation, the volume of the lung tissue is enhanced and the heart tissue is pushed away from the treating breast. Therefore, heart dose of these patients, using DIBH, experiences a considerable decline compared to free breathing treatment. There are a few commercialized systems for implementation of DIBH in invasive or noninvasive manners. Methods: We present a novel constructed noninvasive DIBH device relied on a manufacturing near-field laser distance meter. This in-house constructed system is composed of a CD22-100AM122 laser sensor combined with a data acquisition system for monitoring the breathing curve. Qt Creator (a cross-platform JavaScript, QML, and C++-integrated development environment that is part of the SDK for development of the Qt Graphical User Interface application framework) and Keil MDK-ARM (a programming software where users can write in C and C++ and assemble for ARM-based microcontrollers) are used for composing computer and microcontroller programs, respectively. Results: This system could be mounted in treatment or computed tomography (CT) room at suitable cost; it is also easy to use and needs a little training for personnel and patients. The system can assess the location of chest wall or abdomen in real time with high precision and frequency. The performance of CD22-100AM122 demonstrates promise for respiratory monitoring for its fast sampling rate as well as high precision. It can also deliver reasonable spatial and temporal accuracy. The patient observes his/her breathing waveform through a 7” 1024 × 600 liquid crystal display and gets some instructions during treatment and CT sessions by an exploited algorithm called “interaction scenario” in this study. The system is also noninvasive and well sustainable for patients. Conclusions: The constructed system has true real-time operation and is rapid enough for delivering clear contiguous monitoring. In addition, in this system, we have provided an interaction scenario option between patient and CT or Linac operator. In addition, the constructed system has the capability of sending triggers for turning on and off CT or Linac facilities. In this concern, the system has the superiority of combining a plenty of characteristics.

We performed a dosimetric study to evaluate the benefits of using a flattening-filter-free (FFF) beam with the deep inspiration breath-hold (DIBH) method for left-breast cancer. We used data from 30 previous patients with treatment plans that included DIBH for left-breast cancer with a flattened beam. FFF beam plans were calculated from previous treatment plan images and compared to the original plans in terms of monitor units (MU), number of segments, beam-on time, and breath-holds. Beam-on time was calculated by adding the traveling time of 1.5 second between segments to the time calculated from the MU and dose rate. Breath-holds were calculated based on the beam-on time, assuming 15 s per hold. The FFF beam had increased MU in all cases (mean ± SD: flattened beam, 122.4 ± 9.8 MU; FFF beam, 160.2 ± 17.5 MU). Furthermore, the number of segments increased with the FFF beam in all cases (median [range]: flattened beam, 2 [1 to 3]; FFF beam, 5 [3 to 7]). However, in most cases, the beam-on time was reduced using the FFF beam (mean ± SD: flattened beam, 27.8 ± 7.4 seconds; FFF beam, 13.2 ± 1.7 seconds), although when a 6 MV flattened beam was used there was not a large increase. There were fewer breath-holds in most cases with the FFF beam. Cases using a 4 MV flattened beam also had fewer breath-holds; however, the number of breath-holds was consistent or increased in cases that used a 6 MV flattened beam (median [range]: flattened beam, 3 [1 to 3]; FFF beam, 1 [1 to 2]). [ABSTRACT FROM AUTHOR]

Purpose: To determine the effect of the deep inspiration breath-hold (DIBH) technique on left anterior descending coronary artery (LAD) region and heart dose in left breast cancer irradiation. Materials and Methods: Twenty-five left breast cancer patients who previously received breast-conserving surgery underwent computed tomography (CT) simulation with both free-breathing (FB) and DIBH techniques and four radiation treatment plans. The plan comprised the following with both the FB and DIBH techniques: whole breast (WB), and WB with internal mammary lymph nodes (WB+IMNs). The prescription dose was 50 Gy in 25 fractions. The doses to the LAD region, heart and lungs were compared. Moreover, in-field maximum heart distance (maxHD) and breast volume were analyzed for correlations with the mean heart dose (MHD). Results: In the WB plan with DIBH vs. FB techniques, the mean radiation doses to the LAD region, MHD, and the left lung V20 were 11.48 Gy vs. 19.84 Gy (p < 0.0001), 2.95 Gy vs. 5.38 Gy (p < 0.0001), and 19.72% vs. 22.73% (p = 0.0045), respectively. In the WB+IMNs plan, the corresponding values were 23.88 Gy vs. 31.98 Gy (p < 0.0001), 6.43 Gy vs. 10.24 Gy (p < 0.0001), and 29.31% vs. 32.1% (p = 0.0009), respectively. MHD correlated with maxHD (r = 0.925) and breast volume (r = 0.6). Conclusion: The use of the DIBH technique in left breast cancer irradiation effectively reduces the radiation doses to the LAD region, heart and lungs. MHD is associated with maxHD and breast size. [ABSTRACT FROM AUTHOR]