Voluntary Deep Inspiration Breath Hold Research Articles

Dosimetric Impact of Voluntary Deep Inspiration Breath Hold (DIBH) in Mediastinal Hodgkin Lymphomas: A Comparative Evaluation of Three Different Intensity Modulated Radiation Therapy (IMRT) Delivery Methods Using Voluntary DIBH and Free Breathing Techniques.

Hodgkin lymphomas are radiosensitive and curable tumors that often involve the mediastinum. However, the application of radiation therapy to the mediastinum is associated with late effects including cardiac and pulmonary toxicities and secondary cancers. The adoption of conformal IMRT and deep inspiration breath- hold (DIBH) can reduce the dose to healthy normal tissues (lungs, heart and breast). We compared the dosimetry of organs at risk (OARs) using different IMRT techniques for two breathing conditions, i.e., deep inspiration breath hold (DIBH) and free breathing. Twenty-three patients with early-stage mediastinal Hodgkin lymphomas were accrued in the prospective study. The patients were given treatment plans which utilized full arc volumetric modulated arc therapy (F-VMAT), Butterfly VMAT (B-VMAT), and fixed field IMRT (FF-IMRT) techniques for both DIBH and free breathing methods, respectively. All the plans were optimized to deliver 95% of the prescription dose which was 25.2 Gy to 95% of the PTV volume. The mean dose and standard error of the mean for each OAR, conformity index (CI), and homogeneity index (HI) for the target using the three planning techniques were calculated and compared using Student's t-test for parametric data and Wilcoxon signed-rank test for non-parametric data. The HI and CI of the target was not compromised using the DIBH technique for mediastinal lymphomas. The mean values of CI and HI for both DIBH and FB were comparable. The mean heart doses were reduced by 2.1 Gy, 2.54 Gy, and 2.38 Gy in DIBH compared to FB for the F-VMAT, B-VMAT, and IMRT techniques, respectively. There was a significant reduction in V5Gy, V10Gy, and V15Gy to the heart (p < 0.005) with DIBH. DIBH reduced the mean dose to the total lung by 1.19 Gy, 1.47 Gy, and 1.3 Gy, respectively. Among the 14 female patients, there was a reduction in the mean right breast dose with DIBH compared to FB (4.47 Gy vs. 3.63 Gy, p = 0.004). DIBH results in lower heart, lung, and breast doses than free breathing in mediastinal Hodgkin Lymphoma. Among the different IMRT techniques, FF-IMRT, B-VMAT, and F-VMAT showed similar PTV coverage, with similar conformity and homogeneity indices. However, the time taken for FF-IMRT was much longer than for the F-VMAT and B-VMAT techniques for both breathing methods. B-VMAT and F-VMAT emerged as the optimal planning techniques able to achieve the best target coverage and lower doses to the OARs, with less time required to deliver the prescribed dose.

A Convenient and Effective Preoxygenation Technique for Prolonging Deep Inspiration Breath-Hold Duration With a Venturi Mask With a 50% Oxygen Concentration

Purpose: Voluntary deep inspiration breath-hold (DIBH) is commonly used in radiation therapy (RT), but the short duration of a single breath-hold, estimated to be around 20-40 seconds (s), is a limitation. This prospective study aims to assess the feasibility and safety of using a simple preoxygenation technique with a Venturi mask to prolong voluntary DIBH. Methods and materials: The study included 33 healthy volunteers and 21 RT patients. Preoxygenation was performed using a Venturi mask with a 50% oxygen concentration. Paired t-tests compared the duration of a single DIBH in room air and after 5, 15, and 30 minutes of preoxygenation in healthy volunteers. Sustainability of breath-hold and tolerability of heart rate and blood pressure were assessed for multiple DIBH durations in both volunteers and patients. Results: In healthy volunteers, a 15-minute preoxygenation significantly prolonged the duration of a single DIBH by 24.95s compared to 5-minute preoxygenation (89 ± 27.76s vs. 113.95 ± 30.63s, p < 0.001); although there was a statistically significant increase in DIBH duration following 30-minute preoxygenation, it only extended by 4.95s compared to 15-minute preoxygenation (113.95 ± 30.63s vs. 118.9 ± 29.77s, p < 0.01). After 15-minute preoxygenation, a single DIBH lasted over 100s in healthy volunteers and over 80s in RT patients with no significant differences among six consecutive cycles of DIBH. Furthermore, there were no significant differences in heart rate, or blood pressure after DIBHs, including DIBH in room air and six consecutive DIBH after 15-minute preoxygenation (all p > 0.05). Conclusions: Preoxygenation with a 50% oxygen concentration for 15 minutes effectively prolongs the duration of six cycles of DIBH both in healthy volunteers and RT patients. The utilization of a Venturi mask to deliver 50% oxygen concentration provides a solution characterized by its convenience, good tolerability, and effectiveness.

Evaluation of the voluntary deep inspiration breath-hold reproducibility in left-sided breast radiotherapy.

Voluntary deep inspiration breath hold (v-DIBH) reduces cardiac dose during left-sided breast irradiation. The purpose of this study is to evaluate the reproducibility and variability of breath-hold level (BHL) using breath-hold curves and lateral kV setup images together. A retrospective analysis of 30 left breast cancer patients treated using the v-DIBH technique in our department is performed. The BHL difference is measured from breath hold curves and lateral (LAT) kilo-Voltage (kV) setup images. The planning CT image and the selected treatment fraction data are collected. If the changes in BHL relate to the displacement of various bones in the kV setup, images are assessed. Furthermore, the maximum heart distance inside the treatment field is compared from LAT MV portal images. The median and mean values of the BHL are nearly identical in different fractions (good reproducibility). However, the mean BHL values between planning and all measured fractions are statistically different; 16.3 vs. 20.8 mm for the planning and measured fractions (p < 0.001), which indicates that the variability of BHL is significantly different. While reproducibility testing shows good agreement for inter-fractional breath-hold level, the variability between planning and fractions is relatively poor.

Preoxygenation with a 50% Concentration of Oxygen for 15 Minutes might Safely and Feasibly Prolong the Breath-Hold Duration during Radiotherapy: A Pilot Study

<h3>Purpose/Objective(s)</h3> Voluntary deep inspiration breath-hold (DIBH) has been wildly used during radiation for thoracic and abdominal tumors. While the main disadvantage of voluntary DIBH is its short duration per single breath-hold. Preoxygenation with a high concentration of oxygen (more than 50%) combined with mechanical hyperventilation induced hypocapnia has been used for prolonging the single breath-hold duration, however, its safety is still a concern. In this study, we aimed to investigate whether simple preoxygenation with a relatively safe oxygen concentration of 50% can feasibly prolong the single breath-hold duration. <h3>Materials/Methods</h3> 12 healthy volunteers aged 21-48 years (6 males and 6 females) without previous cardiovascular diseases were included. The single DIBH duration of room air in resting-state, the single DIBH duration of room air after 5 min, 15 min, and 30 min preoxygenation with 50% concentration of oxygen, respectively, were evaluated and compared using paired t-test. <h3>Results</h3> The mean DIBH duration in room air in resting-state was 51.5 ± 12.97 seconds. Compared with DIBH in room air, after 5, 15, and 30 minutes preoxygenation with 50% concentration of oxygen, the DIBH duration in room air was significantly increased up to 91.9 ± 28.3 (p<0.0001), 115.5 ±25.5 (p<0.0001), and 122.1 ±28.4 seconds (p<0.0001), respectively. Furthermore, compared with 5 minutes of preoxygenation, the DIBH duration after 15 and 30 minutes of preoxygenation was significantly increased with 23.5 ± 9.7 (p<0.0001) and 30.2 ± 13.7 seconds (p<0.0001). Compared with 15 minutes of preoxygenation, the DIBH duration after 30 minutes of preoxygenation was only increased with 6.7 ± 5.4 seconds (p=0.0013). <h3>Conclusion</h3> This pilot study demonstrated that simple preoxygenation with a 50% concentration of oxygen for 15 minutes might safely and feasibly prolong the DIBH duration during radiotherapy. Further studies are warranted to confirm these results and to identify how many cycles of a single breath-hold can be prolonged. This study has been supported by the National Nature Science Foundation of China (82171890 & 81701683), Key Research and Development Projects of Zhejiang Provincial Science and Technology Department (2021C03122), Health Commission of Zhejiang Province (2020KY131), and Zhejiang Provincial Key Discipline of Traditional Chinese Medicine (2017-XK-A32).

Inter-fraction heart displacement during voluntary deep inspiration breath hold radiation therapy without visual feedback measured by daily CBCT.

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.

A Comparison of Three Different Breath Hold Techniques Used for Reducing Cardiac Dose for Patients Receiving Left-Sided Breast Cancer Radiation Therapy

Purpose: Cardiac toxicity is a major concern for left-sided breast cancer patients receiving radiation therapy (RT). Different breath-hold techniques may be used to reduce cardiac dose including voluntary deep inspiration breath hold (vDIBH), the Elekta Active Breathing Coordinator (ABC), and the AlignRT system from VisionRT. The purpose of this study is to evaluate the differences in heart position and mean heart dose for these three techniques during RT of left-sided breast cancer patients.

A Randomised Phase II Clinical Trial Comparing the Deliverability and Acute Toxicity of Wide Tangent versus Volumetric Modulated Arc Therapy to the Breast and Internal Mammary Chain

AimsInclusion of the internal mammary chain in the radiotherapy target volume (IMC-RT) improves disease-free and overall survival in higher risk breast cancer patients, but increases radiation doses to heart and lungs. Dosimetric data show that either modified wide-tangential fields (WT) or volumetric modulated arc therapy (VMAT) together with [AQ1]voluntary deep inspiration breath hold (vDIBH) keep mean heart doses below 4 Gy in most patients. However, the impact on departmental resources has not yet been documented. This phase II clinical trial compared the time taken to deliver IMC-RT using either WT and vDIBH or VMAT and vDIBH, together with planning time, dosimetry, set-up reproducibility and toxicity. Materials and methodsLeft-sided breast cancer patients requiring IMC-RT were randomised to receive either WT(vDIBH) or VMAT radiotherapy. The primary outcome was treatment time, powered to detect a minimum difference of 75 min (5 min/fraction) between techniques. The population mean displacement, systematic error and random error for cone beam computed tomography chest wall matches in three directions of movement were calculated. Target volume and organ at risk doses were compared between groups. Side-effects, including skin (Radiation Therapy Oncology Group), lung and oesophageal toxicity (Common Terminology Criteria for Adverse Events v 4.03) rates, were compared between the groups over 3 months. Patient-reported outcome measures, including shoulder toxicity at baseline, 6 months and 1 year, were compared. ResultsTwenty-one patients were recruited from a single UK centre between February 2017 and January 2018. The mean (standard deviation) total treatment time per fraction for VMAT treatments was 13.2 min (1.7 min) compared with 28.1 min (3.3 min) for WT(vDIBH). There were no statistically significant differences in patient set-up errors in between groups. The average mean heart dose for WT(vDIBH) was 2.6 Gy compared with 3.4 Gy for VMAT(vDIBH) (P = 0.13). The mean ipsilateral lung V17Gy was 32.8% in the WT(vDIBH) group versus 34.4% in the VMAT group (P = 0.2). The humeral head (mean dose 16.8 Gy versus 2.8 Gy), oesophagus (maximum dose 37.3 Gy versus 20.1 Gy) and thyroid (mean dose 22.0 Gy versus 11.2 Gy) all received a statistically significantly higher dose in the VMAT group. There were no statistically significant differences in skin, lung or oesophageal toxicity within 3 months of treatment. Patient-reported outcomes of shoulder toxicity, pain, fatigue, breathlessness and breast symptoms were similar between groups at 1 year. ConclusionVMAT(vDIBH) and WT(vDIBH) are feasible options for locoregional breast radiotherapy including the IMC. VMAT improves nodal coverage and delivers treatment more quickly, resulting in less breath holds for the patient. This is at the cost of increased dose to some non-target tissues. The latter does not appear to translate into increased toxicity in this small study.

Assessment of visual feedback system for reproducibility of voluntary deep inspiration breath hold in left-sided breast radiotherapy

IntroductionDeep inspiration breath-hold (DIBH) for left-sided breast cancer radiotherapy reduces the dose exposure of the heart and left anterior descending coronary artery. DIBH requires the patient to maintain an adequate breath-hold position during their daily radiotherapy fraction. This study aimed to assess the reproducibility of the breath-hold position by implementing DIBH with visual feedback (VF) system. MethodsForty-three patients who underwent left-sided radiotherapy with DIBH were reviewed. Data from 35 patients who underwent DIBH with VF (VF-DIBH) were compared with data from 8 patients who underwent DIBH with audio coaching (AC-DIBH). Reproducibility during radiotherapy was evaluated using the portal images obtained. Images were acquired daily during the tangential field treatment with DIBH. The distances between the field edge and chest wall at the central beam axis were manually measured on the portal image and digital reconstruction radiograph (DRR). The displacements of the chest wall during radiotherapy were assessed by subtracting the measurement made on the portal image from the DRR measurement. The overall average distances for the VF-DIBH and AC-DIBH cohorts were compared to assess reproducibility. The statistical analysis was performed using Mann–Whitney U tests (p < 0.05). ResultsThe mean chest wall displacement (±2 SD) was 0.59 ± 3.64 mm for VF-DIBH and 2.09 ± 4.96 mm for AC-DIBH, respectively. This value differed significantly between the VF-DIBH and AC-DIBH cohorts (p < 0.001). ConclusionIn DIBH radiotherapy, the implementation of VF was confirmed to improve breath-hold position reproducibility, and the utility of VF for DIBH was demonstrated.

Dosimetric Efficacy of Voluntary Deep Inspiration Breath-Hold in the Radiotherapy of Left Breast Cancer Patients Using the UK START Trial

Introduction: Deep inspiration breath-hold (DIBH) technique is widely administered to left breast cancer (LBC) patients to reduce the radiation dose to the cardiopulmonary structures. The UK standardization of breast cancer radiotherapy (UK START) dose prescription was found comparable to the conventional schedule. The current study compared voluntary DIBH and free-breathing (FB) methods in the cardiopulmonary radiation doses of LBC patients with supraclavicular irradiation treated with the UK START trial. Materials and Methods: A computed tomography (CT) scan was acquired for a group of 50 LBC patients in DIBH and FB and a radiotherapy plan was created on each scan. The dose-volume histogram (DVH) parameters of the heart and lung were analyzed against their relevant first clinical acceptance criteria using one-sample t-test. Additionally, we assessed the correlation between the ipsilateral lung volume expansion and the cardiopulmonary dosimetric benefits. Results: The DIBH technique significantly reduced the cardiopulmonary doses compared with the FB method (p < 0.001). Furthermore, the mean difference between the mean heart dose (MHD) and its first acceptance criterion was -62.6 cGy (p < 0.001), and the volume of the heart and lung received at least 16 Gy (Heart V16Gy and lung V16Gy, respectively) was lower than their first acceptance criteria by -0.63% and -2.18% (p < 0.001), respectively. In contrast, the first acceptance criteria of the cardiopulmonary dosimetric parameters were not accomplished with the FB method. In addition, the difference in MHD and heart V20Gy between DIBH and FB plans showed a moderate correlation with ipsilateral lung volume expansion (r = 0.51 and 0.5, respectively). Conclusion: The DIBH technique should be served to all locally advanced LBC patients, and the ipsilateral lung volume expansion could be a predictor for the cardiac-sparing radiotherapy in LBC.

Intrafractional fiducial marker position variations in stereotactic liver radiotherapy during voluntary deep inspiration breath-hold.

To evaluate intrafractional fiducial marker position variations during stereotactic body radiotherapy (SBRT) in patients treated for liver metastases in visually guided, voluntary deep inspiration breath-hold (DIBH). 10 patients with implanted fiducial markers were studied. Respiratory coaching with visual guidance was used to ensure comfortable voluntary breath-holds for SBRT imaging and delivery. Three DIBH CTs were acquired for treatment planning. Pre- and post-treatment CBCTs were acquired for each of the three treatment fractions. Per-fraction marker position was evaluated on planar 2D kV images acquired during treatment fractions for 4 of the 10 patients. The median difference in marker position was 0.3 cm (range, 0.0-0.9 cm) between the three DIBH CTs and 0.3 cm (range, 0.1 to 1.4 cm) between pre- and post-treatment CBCTs. The maximum intrafractional variation in marker position in craniocaudal (CC) direction on planar kV images was 0.7 to 1.3 cm and up to 1.0 cm during a single DIBH. Difference in marker position of up to 1.0 cm was observed during a single DIBH despite use of narrow external gating window and visual feedback. Stability examination on pre-treatment DIBH CTs was not sufficient to guarantee per-fraction stability. Evaluation of differences in marker position on pre- and post-treatment CBCT did not always reveal the full magnitude of the intrafractional variation. To increase treatment accuracy, it is necessary to apply real-time monitoring of the tumour or a reliable internal surrogate when delivering liver SBRT in voluntary DIBH.

118P Should DIBH (deep inspiration breath-hold) be the standard of care in LBC (left breast cancer)?

Radiotherapy is the most effective treatment to eradicate the residual locoregional disease after breast cancer surgery with significative survival improvements after 15 years post diagnostic. For women receiving left-breast radiotherapy (DIBH) is used to further mitigate mortality and morbidity due to late cardiac toxicity, with a demonstrated linear relationship with Mean Heart Dose (MHD). The risk increases 7.4% per Gy, starting within the first 5 years and continuing into the third decade after radiotherapy. The aim of this study was to evaluate the effect of DIBH irradiation on MHD, V16, V8, V4 and mean, maximum and D10% left anterior descending coronary artery (LADCA) dose. 75 patients with left breast cancer (LBC), after radical mastectomy or conservative surgery, that were able to maintain voluntary DIBH ≥ 20 seconds, were irradiated with this cardiac sparring approach. All patients received hypofractionated radiotherapy (total dose of 40.05Gy / 2.67Gy per fraction) with 58 receiving a concomitant boost (total dose of 48Gy / 3.2Gy per fraction) and 9 patients having axillary nodes irradiated. The target volume was delineated on CT in DIBH and Free Breathing (FB) according to the ESTRO consensus guideline and heart according to the CT-based atlas by Feng et al. Tangent-based intensity modulated radiation therapy (n: 71) or VMAT (n: 4) plans were developed for both datasets. Patient set-up and tracking in FB/DIBH was monitored by Surface Guided Radiation Therapy (VisionRT, London, UK), after daily validation by cone beam CT matching. DIBH reduces significantly MHD, V16, V8, V4 and mean, maximum and D10% LAD dose compared to FB (p = 0.001). This difference is irrespective of breast PTV volume (797±367.6 cm3) or boost PTV volume (75.3 ± 30.3cm3). DIBH average MHD was 1.20 Gy (0.87-1.62) and average LADCA Dmean of 4.95 Gy (2.79-9.14) with respectively in FB 3.18 Gy (2.47-4.26) and 20.20Gy (12.29.-25.40). DIBH in LBC does lead to a significant reduction in heart and LADCA doses by increasing the distance between target and heart. These reductions could contribute to increase cardiovascular health of LBC. These findings apply to all patients and further studies will indicate to which subgroups the benefits are more pronounced.

107P - A comparative study of voluntary deep inspiration breath hold versus free breathing techniques in adjuvant left breast hypofractionated radiotherapy

107P - A comparative study of voluntary deep inspiration breath hold versus free breathing techniques in adjuvant left breast hypofractionated radiotherapy

267P - Voluntary deep inspiration breathhold (DIBH) experience in the radiotherapy for left sided breast cancer

267P - Voluntary deep inspiration breathhold (DIBH) experience in the radiotherapy for left sided breast cancer

In-vivo dosimetry comparison of supraclavicular junction dose for breast and chest-wall patients with and without deep inspiration breath hold (DIBH)

PurposeThe use of deep inspiration breath-hold (DIBH) for patients with left-sided breast cancer reduces cardiac dose, with the aim of reducing the risk of major coronary events. However, this technique has not been universally adopted for patients requiring regional nodal irradiation (RNI) with one concern related to the junction dose. This study evaluates the dose received at the junction for both DIBH and free-breathing patients having tangential breast/chest wall radiation and regional nodal radiation treated with 3D-conformal or hybrid IMRT radiotherapy. MethodsIn-vivo dosimetry measurements utilizing EBT3 GafChromic™ film were performed for 19 patients during three fractions over their course of treatment. The mean junction dose and variability in junction dose were compared between the DIBH and free breathing patients. ResultsOur results show that for voluntary DIBH (v-DIBH) patients the junction dose is more variable between fractions. However, when comparing the average junction dose for DIBH and free breathing patients over the three measurements, the difference was small and not statistically significant. A larger difference was seen when patient measurements were analysed based on treatment linac. ConclusionsThese results show that the mean junction dose is not significantly compromised by the use of v-DIBH. The small possibility of a change in junction dose due to breathing technique should be weighed against the proven increased risks associated with excess cardiac dose received by free-breathing patients. If junction dose is of concern, an in-vivo study, such as this one, could allow cautious introduction of DIBH for patients requiring supraclavicular irradiation.

Single-institution report of setup margins of voluntary deep-inspiration breath-hold (DIBH) whole breast radiotherapy implemented with real-time surface imaging.

PurposeWe calculated setup margins for whole breast radiotherapy during voluntary deep‐inspiration breath‐hold (vDIBH) using real‐time surface imaging (SI).Methods and MaterialsPatients (n = 58) with a 27‐to‐31 split between right‐ and left‐sided cancers were analyzed. Treatment beams were gated using AlignRT by registering the whole breast region‐of‐interest to the surface generated from the simulation CT scan. AlignRT recorded (three‐dimensional) 3D displacements and the beam‐on‐state every 0.3 s. Means and standard deviations of the displacements during vDIBH for each fraction were used to calculate setup margins. Intra‐DIBH stability and the intrafraction reproducibility were estimated from the medians of the 5th to 95th percentile range of the translations in each breath‐hold and fraction, respectively.ResultsA total of 7269 breath‐holds were detected over 1305 fractions in which a median dose of 200 cGy was delivered. Each fraction was monitored for 5.95 ± 2.44 min. Calculated setup margins were 4.8 mm (A/P), 4.9 mm (S/I), and 6.4 mm (L/R). The intra‐DIBH stability and the intrafraction reproducibility were ≤0.7 mm and ≤2.2 mm, respectively. The isotropic margin according to SI (9.2 mm) was comparable to other institutions’ calculations that relied on x‐ray imaging and/or spirometry for patients with left‐sided cancer (9.8–11.0 mm). Likewise, intra‐DIBH variability and intrafraction reproducibility of breast surface measured with SI agreed with spirometry‐based positioning to within 1.2 and 0.36 mm, respectively.ConclusionsWe demonstrated that intra‐DIBH variability, intrafraction reproducibility, and setup margins are similar to those reported by peer studies who utilized spirometry‐based positioning.

Patient Comfort and Treatment Efficiency of Voluntary Deep Inspiration Breath Hold

Voluntary deep inspiration breath hold (vDIBH) has been proven to be a beneficial technique to reduce heart dose in breast treatments. There are several different pieces of equipment that can be used to deliver this treatment and each should be studied for its level of comfort and reproducibility as for the overall efficiency of the treatment. This study focused on the patient comfort and treatment efficiency of vDIBH when using the MedSpira® Breath Hold ES Equipment. This was a retrospective study that compiled data from 10 patients that had been pre-selected to participate in a vDIBH pilot study. Timestamps and relevant notes from each patient’s treatment chart were recorded as well as responses from a patient satisfaction questionnaire and patient interview. Input from the treating therapists was also recorded as they provided insight into the changes that occurred and difficulties that were encountered. All of this information was recorded in an Excel document and analysed using basic statistical tests and content analysis. The average total length of time for first day treatments was 31 minutes while the average total length of time for successive treatments was 18 minutes. Steps were taken throughout treatment to improve patient comfort, such as eliminating the MedSpira® light display and relying on verbal coaching from the therapists. This was partly due to the patients reporting a difficulty of 5.75/10 on the patient questionnaire regarding difficulty following the light signals. Patients reported the clarity of breathing instructions to be an average of 8.89/10. The level of difficulty of the vDIBH treatment decreased from a 2.78/10 in the first week to a 1.44/10 in the final week. A first day appointment time of 1 hour is acceptable while successive days may be able to be reduced from 45 minutes to 30 minutes. Overall the process was already very efficient with only a few suggestions provided to improve efficiency such as eliminating the drawing of a lateral DIBH mark every day on the treatment unit and tattooing the anterior DIBH mark in CT. Patients who were exposed to the verbal coaching preferred that over the Medspira® light system as they did not find the light system an accurate representation of their breath hold. Patients also relied heavily on the feedback from the therapists and trusted their decisions therefore it is imperative to have confident and knowledgeable therapists delivering these treatments. One recommendation that arose from the analysis of this study was to create a video to teach patients how to breath properly and how to practice prior to their treatment.

Implementation of a voluntary deep inspiration breath hold technique (vDIBH) using BrainLab ExacTrac infrared optical tracking system.

BackgroundVoluntary deep inspiration breath hold technique (vDIBH) is considered as the key to achieving the widest cardiac sparing in whole breast irradiation. Several techniques have been implemented to achieve a reproducible, fast and friendly treatment. The aim of the present study is to implement vDIBH using the ExacTrac (BrainLAB AG, Germany) monitoring system.MethodsWomen with left-sided breast cancer, younger than 50 years or with cardiac disease, underwent whole breast RT with vDIBH using the ExacTrac (BrainLAB AG, Germany) monitoring system. Simulations were performed with patients positioned supine on a breast board with both arms raised above the head. Five optical markers were placed on the skin around the border of the left breast gland and their position was referenced with ink marking. Each patient received a training session to find the individual deep inspiration level. Finally, a vDIBH CT was taken. All patients were also studied in free breathing (FB) in order to compare the dose distribution for PTV, heart and left anterior descending coronary artery (LAD). Pre-treatment verification was carried out through the ExacTrac (BrainLAB AG, Germany) system and verified with electronic portal imaging (EPI). Moreover, daily real time EPIs in during modality (captured during the beam delivery) were taken in order to check the reproducibility.Results34 patients have been evaluated and 30 were eligible for vDIBH. Most patients showed small setup errors during the treatment course of below 5 mm in 94.9% of the recorded fields. Mean Displacement was less in cranio-caudal direction. Mean intra-fraction displacement was below 3 mm in all directions. vDIBH plans provided better cardiac dosimetry.ConclusionsvDIBH technique using ExacTrac (BrainLAB AG, Germany) monitoring system was applied with good reproducibility.

EP-1257: Voluntary Deep Inspiration Breathhold (DIBH) in the Radiotherapy for Breast Cancer

EP-1257: Voluntary Deep Inspiration Breathhold (DIBH) in the Radiotherapy for Breast Cancer

Voluntary Deep Inspiration Breath-hold Reduces the Heart Dose Without Compromising the Target Volume Coverage During Radiotherapy for Left-sided Breast Cancer.

BackgroundDuring radiotherapy of left-sided breast cancer, parts of the heart are irradiated, which may lead to late toxicity. We report on the experience of single institution with cardiac-sparing radiotherapy using voluntary deep inspiration breath hold (V-DIBH) and compare its dosimetric outcome with free breathing (FB) technique.Patients and methodsLeft-sided breast cancer patients, treated at our department with postoperative radiotherapy of breast/chest wall +/– regional lymph nodes between May 2015 and January 2017, were considered for inclusion. FB-computed tomography (CT) was obtained and dose-planning performed. Cases with cardiac V25Gy ≥ 5% or risk factors for heart disease were coached for V-DIBH. Compliant patients were included. They underwent additional CT in V-DIBH for planning, followed by V-DIBH radiotherapy. Dose volume histogram parameters for heart, lung and optimized planning target volume (OPTV) were compared between FB and BH. Treatment setup shifts and systematic and random errors for V-DIBH technique were compared with FB historic control.ResultsSixty-three patients were considered for V-DIBH. Nine (14.3%) were non-compliant at coaching, leaving 54 cases for analysis. When compared with FB, V-DIBH resulted in a significant reduction of mean cardiac dose from 6.1 +/– 2.5 to 3.2 +/– 1.4 Gy (p < 0.001), maximum cardiac dose from 51.1 +/– 1.4 to 48.5 +/– 6.8 Gy (p = 0.005) and cardiac V25Gy from 8.5 +/– 4.2 to 3.2 +/– 2.5% (p < 0.001). Heart volumes receiving low (10–20 Gy) and high (30–50 Gy) doses were also significantly reduced. Mean dose to the left anterior coronary artery was 23.0 (+/– 6.7) Gy and 14.8 (+/– 7.6) Gy on FB and V-DIBH, respectively (p < 0.001). Differences between FB- and V-DIBH-derived mean lung dose (11.3 +/– 3.2 vs. 10.6 +/– 2.6 Gy), lung V20Gy (20.5 +/– 7 vs. 19.5 +/– 5.1 Gy) and V95% for the OPTV (95.6 +/– 4.1 vs. 95.2 +/– 6.3%) were non-significant. V-DIBH-derived mean shifts for initial patient setup were ≤ 2.7 mm. Random and systematic errors were ≤ 2.1 mm. These results did not differ significantly from historic FB controls.ConclusionsWhen compared with FB, V-DIBH demonstrated high setup accuracy and enabled significant reduction of cardiac doses without compromising the target volume coverage. Differences in lung doses were non-significant.

Three-dimensional dose evaluation in breast cancer patients to define decision criteria for adaptive radiotherapy

Background: Dose-guided adaptive radiation therapy (DGART) is the systematic evaluation and adaptation of the dose delivery during treatment for an individual patient. The aim of this study is to define quantitative action levels for DGART by evaluating changes in 3D dose metrics in breast cancer and correlate them with clinical expert evaluation.Material and methods: Twenty-three breast cancer treatment plans were evaluated, that were clinically adapted based on institutional IGRT guidelines. Reasons for adaptation were variation in seroma, hematoma, edema, positioning or problems using voluntary deep inspiration breath hold. Sixteen patients received a uniform dose to the breast (clinical target volume 1; CTV1). Six patients were treated with a simultaneous integrated boost to CTV2. The original plan was copied to the CT during treatment (re-CT) or to the stitched cone-beam CT (CBCT). Clinical expert evaluation of the re-calculated dose distribution and extraction of dose-volume histogram (DVH) parameters were performed. The extreme scenarios were evaluated, assuming all treatment fractions were given to the original planning CT (pCT), re-CT or CBCT. Reported results are mean ± SD.Results: DVH results showed a mean dose (Dmean) difference between pCT and re-CT of -0.4 ± 1.4% (CTV1) and −1.4 ± 2.1% (CTV2). The difference in V95% was −2.6 ± 4.4% (CTV1) and −9.8 ± 8.3% (CTV2). Clinical evaluation and DVH evaluation resulted in a recommended adaptation in 17/23 or 16/23 plans, respectively. Applying thresholds on the DVH parameters: Dmean CTV, V95% CTV, Dmax, mean lung dose, volume exceeding 107% (uniform dose) or 90% (SIB) of the prescribed dose enabled the identification of patients with an assumed clinically relevant dose difference, with a sensitivity of 0.89 and specificity of 1.0. Re-calculation on CBCT imaging identified the same plans for adaptation as re-CT imaging.Conclusions: Clinical expert evaluation can be related to quantitative DVH parameters on re-CT or CBCT imaging to select patients for DGART.