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Copyright of Journal of Medical Imaging & Radiation Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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

Introduction: Active Breathing Control (ABC) is a motion management strategy that facilitates reproducible breath-hold for thoracic radiotherapy (RT), which may reduce radiation dose to organs at risk (OARs). Reduction of radiation-induced toxicity is of high importance in younger patients. However, there is little published literature on the feasibility of ABC in this group. The purpose of this study was to report our experience of using ABC for paediatric and teenage patients. Methods: Patients ≤18 years referred for thoracic RT using ABC at our centre from 2013–2021 were identified. Electronic records were retrospectively reviewed to obtain information on diagnosis, RT dose and technique, OAR dosimetry, tolerability of ABC, post-treatment imaging and early toxicity rates. Results: 12 patients completed RT and were able to comply with ABC during planning and for the duration of RT. Median age was 15.5 years (10–18 years). Diagnoses were: Hodgkin lymphoma (n = 5), mediastinal B-cell lymphoma (n = 1), Ewing sarcoma (n = 5) and rhabdomyosarcoma (n = 1). For mediastinal RT cases (n = 6), median dose delivered was 30.6Gy(19.8–40Gy), median mean heart dose was 11.4Gy(4.8–19.4Gy), median mean lung dose was 9.9Gy(5.7–14.5Gy) and mean lung V20 was 10.9%. For ipsilateral RT cases, (n = 6), median hemithorax and total doses to primary tumour were 18Gy(15–20Gy) and 52.2Gy(36–60Gy) respectively. Median mean heart dose was 19.5Gy(10.6–33.2Gy) and median mean lung dose was 17.7Gy(16.3–30.5Gy). Mean bilateral lung V20 was 39.6%. Median mean contralateral lung dose was 5.2Gy(3.5–11.6Gy) and mean contralateral lung V20 was 1.5%. At a median follow-up of 36 months, only 1 patient had symptomatic radiation pneumonitis having received further thoracic RT following relapse. Conclusions: ABC is feasible and well tolerated in younger patients receiving RT. Children as young as 10 years are able to comply. Use of ABC results in OAR dosimetry which is comparable to similar data in adults and can facilitate RT for extensive thoracic sarcoma

Background: Adverse effects of breast irradiation have been an important concern given the increased survival of early stage breast cancer (ESBC) patients with more effective treatments. However, there is paucity of data on the utility of Active Breathing Control (ABC) technique for right-sided ESBC patients. In this study, we assessed the incorporation of ABC into adjuvant Radiation Therapy (RT) of right-sided ESBC patients and report our dosimetric results.Methods: Thirty-six patients receiving whole breast irradiation followed by a sequential tumor bed boost were included in the study. All patients received field-in-field intensity modulated radiation therapy with incorporation of active breathing control-moderate deep inspiration breath-hold (ABC-mDIBH) after breast conserving surgery. Dose-volume parameters in both plans with and without ABC-mDIBH were compared using Mann-Whitney U test.Results: Mean lung dose decreased from 7 Gy to 5.2 Gy (26% reduction) for the total lung (p < 0.001) and from 12.6 to 9.4 Gy (25% reduction) for the ipsilateral lung (p < 0.001). Mean dose decreased from 4.6 Gy to 1.7 Gy (58% reduction) for liver (p < 0.001) and 1.7 Gy to 1.4 Gy (16% reduction) for the heart (p < 0.001).Conclusion: Our study revealed that incorporation of ABC-mDIBH into adjuvant RT of right-sided ESBC patients results in significantly improved critical organ sparing. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of breath‐hold reproducibility on liver motion using a respiratory motion management device. Methods: Forty‐four patients with hepatic tumors, treated with SBRT with breath‐hold, were randomly selected for this study. All patients underwent three consecutive computed tomography (CT) scans using active breath‐hold coordinator (ABC) with three repeated single breath‐hold during simulation. The three CT scans were labeled as ABC1‐CT, ABC2‐CT, and ABC3‐CT. Displacements of centroids of the entire livers among the three ABC‐CTs were measured as a surrogate for intrafractional motion. For each patient, two different treatment plans were prepared: (a) a clinical plan using a 5‐mm expansion of an ITV that encompassed all three GTVs from each of the three ABC‐CTs, and (b) a research plan using a 5‐mm expansion of the GTV from only ABC1‐CT to create PTV. The clinical plan acceptance criteria were that 95% of the PTV and 99% of the GTV received 100% of the prescription dose. Dosimetric endpoints were analyzed and compared for the two plans. Results: All shifts in the medial‐lateral direction (range: −3.9 to 2.0 mm) were within 5 mm while 7% of shifts in the anterior–posterior direction (range: −10.5 to 16.7 mm) and 11% of shifts in the superior–inferior direction (range: −17.0 to 8.7 mm) exceeded 5 mm. Six patients (14%) had an intrafraction motion greater than 5 mm in any direction. For these six patients, if a plan was created based on a PTV from a single CT (ex. ABC1‐CT), 5 of 12 GTVs captured from other ABC‐CTs would fail to meet the clinical acceptance criteria due to poor breath‐hold reproducibility. Conclusions: Non‐negligible intrafractional motion occurs in patients with poor breath‐hold reproducibility. To identify this subgroup of patients, acquiring three CTs with active breath‐hold during simulation is a feasible practical method. [ABSTRACT FROM AUTHOR]

Objective: the comparison of the radiation load to the organs at risk for three modes of radiation treatment of the breast cancer patients.Materials and methods. The research includes the dosimetric radiation treatment plans for the 20 breast cancer patients with the left-side localization. They all underwent a computed tomography (CT) scan in standard supine position in free-breathing (FB), supine position with active breathing control (ABC) device in deep inspiratory breath hold, and prone position in free-breathing (PP). Three-dimensional treatment plans were made for all 3 CTs. The dose valuations for 3D-planning were carried out for three CT-series. For each mode of radiation the doze-volume parameters of organs at risk were estimated: heart volume exposed to more than 25 Gy (V25 heart), mean dose (Dmean) to the heart and left anterior descending coronary artery (LAD).Results. For all cases the contoured heart volume varied from 477–1056 cm3, with medium volume 769 cm3. The best marks such as V25 heart, Dmean heart and Dmean LAD, were achieved with on supine position with ABC method (4.25 %, 3.13 Gy, 1.3 Gy, respectively) in comparison with FB (9.49 %, 4.96 Gy, 1.95 Gy, respectively) and PP (12.8 %, 9.06 Gy, 24.18 Gy, respectively) (V25 heart: p = 0.00153; Dmean heart: p = 0,000; Dmean LAD: p = 0.00088), when both the breast and the axillary nodes were included in the volume. The advantage of the dosimetric indexes for FB and ABC did not change while axillary and supraclavicular nodes were added to the radiation volume ABC (V25 heart 3.49 %, Dmean heart 3.07 Gy, Dmean LAD 13.8 Gy) in comparison with FB methods (V25 heart 7.91 %, Dmean heart 4.99 Gy, Dmean LAD 19.89 Gy) (V25 heart: p = 0.00205; Dmean heart: p = 0.004; Dmean LAD: p = 0.03).Conclusion. Radiation treatment of the breast cancer patients in the position with ABC contributed to the statistically significant reduction of the dosimetric parameters: V25 heart, Dmean heart and Dmean LAD.

Historically, heart dose from left-sided breast radiotherapy has been associated with a risk of cardiac injury. Data suggests that there is not a threshold for the deleterious effects from radiation on the heart. Over the past several years, advances in radiation delivery techniques have reduced cardiac morbidity due to treatment. Deep inspiration breath hold (DIBH) is a technique that takes advantage of a more favorable position of the heart during inspiration to minimize heart doses over a course of radiation therapy. In the accompanying review article, we outline several methods used to deliver treatment with DIBH, quantify the benefits of DIBH treatment, discuss considerations for patient selection, and identify challenges associated with DIBH techniques.

Purpose: In radiation therapy, the computer-assisted deep inspiration breath-hold (DIBH) technique is one approach to deal with respiratory motion of tumors in the lung, liver, or upper abdomen. However, inter- and intra-breath-hold deviations from an optimal static tumor position might occur. A novel method is presented to noninvasively measure the diaphragm position and thus estimate its residual deviation (as surrogate for the tumor position) based on cone-beam computed tomography (CBCT) projection data using active breathing control during acquisition.Methods: The diaphragm dome (DD) position relative to the isocenter of a linear accelerator is known from the static (DIBH) planning CT. A ball-bearing phantom (BB) is placed at this position, a CBCT dataset is acquired, and in each projection the position of the projected BB is determined automatically based on thresholding. The position of the DD is determined manually in CBCT projections of a patient. The distance between DD and BB (ideal static setting) in craniocaudal direction is calculated for a given angle based on the distance in the projection plane and the relative position of the BB referring to the source and the detector. An angle-dependent correction factor is introduced which takes this geometrical setting into account. The accuracy of the method is assessed.Results: The method allows a CBCT projection-based estimation of the deviation between the DD and its optimal position as defined in the planning CT, i.e., the residual motion of the DD can be assessed. The error of this estimation is 2.2 mm in craniocaudal direction.Conclusions: The developed method allows an offline estimation of the inspiration depth (inter- and intra-breath-hold) over time. It will be useful as a reference for comparison to other methods of residual motion estimation, e.g., surface scanning. [ABSTRACT FROM AUTHOR]

Historically, heart dose from left-sided breast radiotherapy has been associated with a risk of cardiac injury. Data suggests that there is not a threshold for the deleterious effects from radiation on the heart. Over the past several years, advances in radiation delivery techniques have reduced cardiac morbidity due to treatment. Deep inspiration breath hold (DIBH) is a technique that takes advantage of a more favorable position of the heart during inspiration to minimize heart doses over a course of radiation therapy. In the accompanying review article, we outline several methods used to deliver treatment with DIBH, quantify the benefits of DIBH treatment, discuss considerations for patient selection, and identify challenges associated with DIBH techniques. [ABSTRACT FROM AUTHOR]

Purpose This study determined the dosimetric comparison of moderate deep inspiration breath-hold using active breathing control and free-breathing intensity-modulated radiotherapy (IMRT) after breast-conserving surgery for left-sided breast cancer. Patients and methods Thirty-one patients were enrolled. One free breathe and two moderate deep inspiration breath-hold images were obtained. A field-in-field-IMRT free-breathing plan and two field-in-field-IMRT moderate deep inspiration breath-holding plans were compared in the dosimetry to target volume coverage of the glandular breast tissue and organs at risks for each patient. Results The breath-holding time under moderate deep inspiration extended significantly after breathing training ( P < 0.05). There was no significant difference between the free-breathing and moderate deep inspiration breath-holding in the target volume coverage. The volume of the ipsilateral lung in the free-breathing technique were significantly smaller than the moderate deep inspiration breath-holding techniques ( P < 0.05); however, there was no significant difference between the two moderate deep inspiration breath-holding plans. There were no significant differences in target volume coverage between the three plans for the field-in-field-IMRT (all P > 0.05). The dose to ipsilateral lung, coronary artery and heart in the field-in-field-IMRT were significantly lower for the free-breathing plan than for the two moderate deep inspiration breath-holding plans (all P < 0.05); however, there was no significant difference between the two moderate deep inspiration breath-holding plans. Conclusion The whole-breast field-in-field-IMRT under moderate deep inspiration breath-hold with active breathing control after breast-conserving surgery in left-sided breast cancer can reduce the irradiation volume and dose to organs at risks. There are no significant differences between various moderate deep inspiration breath-holding states in the dosimetry of irradiation to the field-in-field-IMRT target volume coverage and organs at risks. [ABSTRACT FROM AUTHOR]

Background: Liver metastases may occur during the course of several cancer types and may be associated with significant morbidity and mortality. There is paucity of data regarding the utility of Active Breathing Control (ABC) guided Stereotactic Ablative Body Radiotherapy (SABR) for management of Liver Metastases from Colorectal Cancer (LMCC). Our aim is to investigate the role of ABC guided SABR for management of liver metastases., Patients and Methods: 42 liver metastases of 29 patients treated with ABC guided SABR between February 2015 and October 2018 were retrospectively assessed for local control (LC), overall survival (OS), and toxicity outcomes. Primary endpoint was LC. Secondary endpoints were OS and treatment toxicity., Results: At a median follow up duration of 16 months (range: 9-74 months), median OS was 20 months and 3 patients were still alive at last follow up. 1-year OS was 83% and 2-year OS was 28%. LC rates were 92% and 61% at 1 and 2 years, respectively. Comparative analysis of Biological Effective Dose (BED) values revealed that higher BED10 values were associated with higher LC rates (p=0.007). While LC rates for BED10 ≥ 100 Gray (Gy) were 94% and 86% at 1 and 2 years, corresponding LC rates for BED10 < 100 Gy were 89% and 36%, respectively with statistical significance (p=0.007). Assessment of acute and late toxicity outcomes revealed that most common toxicity was fatigue, however, no patients had ≥ grade 3 toxicity., Conclusion: ABC guided SABR is an effective and safe treatment modality for LMCC management., Competing Interests: The authors declare that they have no conflict of interest, (© Acta Gastro-Enterologica Belgica.)

Copyright of Journal of Medical Imaging & Radiation Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this study was to evaluate the feasibility and benefits of using high-dose-rate three-dimensional conformal radiotherapy (3D-CRT) combined with active breathing control (ABC) for stereotactic body radiotherapy (SBRT) of patients with early-stage non-small-cell lung cancer (NSCLC). Eight patients with early-stage NSCLC underwent CT scans under standard free-breathing (FB) and moderately deep inspiration breath-hold (mDIBH) with ABC. Two high-dose-rate 3D-CRT plans (1000 Mu/min) were designed based on the CT scans with FB and mDIBH. The maximal dose (D1%), minimal dose (D99%), conformity index (CI), and homogeneity index (HI) of the planning target volume (PTV), and dose-volume indices of the organs at risk between each plan were compared. The mean PTV volume decreased from 158.04 cm(3) with FB to 76.90 cm(3) with mDIBH (p < 0.05). When mDIBH was used, increases in the affected lung volume (by 47%), contralateral lung volume (by 55%), and total lung volume (by 50%) were observed compared to FB (p < 0.05). The V5-V40 of the affected lung (Vx represented the percentage volume of organs receiving at least the x Gy), V5-V40 and the mean dose for the total lung, V5-V40 and mean dose of the chest wall, and the maximum dose of the spinal cord were less for mDIBH than FB (p < 0.05). There were no significant differences in CI, HI, D1%, or D99% for the PTV between the plans. In conclusion, high-dose-rate 3D-CRT combined with ABC reduced the radiation dose to the lungs and chest wall without affecting the dose distribution in SBRT of early-stage NSCLC patients., (© The Author(s) 2014.)