Deep Inspiration Breath Hold CT Research Articles

How Effective is Deep Inspiration Breath Hold in Minimizing Cardiac Doses During Hybrid Radiotherapy Treatment for Left-Sided Breast Cancer with Comprehensive Regional Nodes?

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

Dosimetric analysis of half-field-based VMAT with the deep inspiration breath-hold technique for left breast cancer patients following breast-conserving surgery.

Compared the dosimetric characteristics of half-field-based VMAT and half-field-based IMRT for left breast cancer patients combined with deep inspiration breath-hold (DIBH) and free breathing (FB) techniques. Twenty-one left breast cancer patients were included. Each patient underwent DIBH and FB CT scans, IMRT and VMAT plans in half-field beam mode for both breathing techniques, resulting in four plans: FB-IMRT (F-IMRT), FB-VMAT (F-VMAT), DIBH-IMRT (D-IMRT) and DIBH-VMAT (D-VMAT). The conformity index (CI), homogeneity index (HI), and the doses received at the heart, left anterior descending (LAD), left lung, right breast, and right lung, were compared among plans.The correlation between the difference in the volume of lung_L (ΔLVL) and the difference in the mean dose (ΔDmean) of lung_L under the DIBH and FB plans, the correlation between the difference in the heart-chest distance (ΔHCD) and the ΔDmean of the heart,LAD under the DIBH and FB plans. The D-VMAT plan lower lung_L V5 than both the F-IMRT and F-VMAT plans (p<0.05), The D-VMAT plan lower values for V10, V20, V30, and Dmean than did the other plans (p < 0.05). For the heart, the D-VMAT plan lower V5, V10, V20, and Dmean values than did the other plans (p < 0.05). The D1% and Dmax of the heart and the Dmax and Dmean of the LAD obtained with the D-VMAT plan were lower than those obtained with the F-IMRT and F-VMAT plans (p < 0.05). ΔHCD exhibited correlation with the ΔDmean of the LAD between the D-VMAT and F-IMRT plans and between the D-VMAT and F-VMAT plans (R = -0.765 and -0.774, respectively, p = 0.000). the D-VMAT plan offered enhanced protection for OARs. The integration of the DIBH technique with half-field and VMAT technology in the D-VMAT plan offers a superior dose distribution.

Stereoscopic X-ray image and thermo-optical surface guidance for breast cancer radiotherapy in deep inspiration breath-hold

PurposeTo investigate the feasibility of a thermo-optical surface imaging (SGRT) system combined with room-based stereoscopic X‑ray image guidance (IGRT) in a dedicated breast deep inspiration breath-hold (DIBH) irradiation workflow. In this context, benchmarking of portal imaging (EPID) and cone-beam CT (CBCT) against stereoscopic X‑rays was performed.MethodsSGRT + IGRT data of 30 left-sided DIBH breast patients (1 patient with bilateral cancer) treated in 351 fractions using thermo-optical surface imaging and X-ray IGRT were retrospectively analysed. Patients were prepositioned based on a free-breathing surface reference derived from a CT scan. Once the DIBH was reached using visual feedback, two stereoscopic X‑ray images were acquired and registered to the digitally reconstructed radiographs derived from the DIBH CT. Based on this registration, a couch correction was performed. Positioning and monitoring by surface and X-ray imaging were verified by protocol-based EPID or CBCT imaging at selected fractions and the calculation of residual geometric deviations.ResultsThe median X‑ray-derived couch correction vector was 4.9 (interquartile range [IQR] 3.3–7.1) mm long. Verification imaging was performed for 134 fractions (216 RT field verifications) with EPID and for 37 fractions with CBCT, respectively. The median 2D/3D deviation vector length over all verification images was 2.5 (IQR 1.6–3.9) mm/3.4 (IQR 2.2–4.8) mm for EPID/CBCT, both being well within the planning target volume (PTV) margins (7 mm). A moderate correlation (0.49–0.65) was observed between the surface signal and X-ray position in DIBH.ConclusionDIBH treatments using thermo-optical SGRT and X-ray IGRT were feasible for breast cancer patients. Stereoscopic X‑ray positioning was successfully verified by standard IGRT techniques.

Inaugural Experience with Real-time Gated Liver Proton SBRT and Treatment Plan Quality Improvement

DIBH SBRT is routinely used for liver proton therapy. While intra-fraction target motion is limited with DIBH, acquisition of DIBH CT simulations in triplicate, as is done at our institution, reveals that variation does exist between each DIBH scan. The related target position can also vary correspondingly. The most common setup uncertainty for robust proton SBRT liver plan used at our institution is 5 mm sup-inf (SI) and 3 mm radially. Real-time gated proton therapy (RGPT) has the potential to provide instantaneous feedback for intra-fraction target motion to maximize patient safety and inform optimal treatment planning. Our first RGPT liver SBRT with intra-fraction motion under deep inspiration breath hold (DIBH). The potential treatment plan quality improvement brought by RGPT is investigated. The following metrics were used in establishing our RGPT proton DIBH SBRT liver program: the iso center is always set at the fiducial mark; the beam orientation is selected to achieve both good plan quality and tracking performance; daily CBCTs are acquired and verified using fiducial maker position with kV images; robust uncertainty is determined by the gating tolerance; SBRT plan has three beams with uniform dose. Target motion was monitored throughout treatment. To evaluate dose sparing for surrounding OARs, a plan with tighter gating tolerance (3 mm SI and 2 mm radially) is optimized for dosimetric comparison. Statistical analyses were conducted using a programming environment. Each of the three proton beams were delivered using DIBH over a total of 120-140 seconds. The average beam on time were 61.4, 66.9 and 62.8 seconds. The intra-fraction motion showed that targets could move up to 3 mm within the same DIBH. The motion increased with time. The table details the mean, maximum, standard deviation, and estimated upper 95% of directional shifts for three beams. Based on these results, plan delivery efficiency was maintained even with tighter gating tolerance. The comparison plan with tight gating tolerance showed significantly less dose (-25%) to the stomach in coronal view. RGPT successfully tracked fiducial marker motion for DIBH SBRT liver treatment. Despite target drift during DIBH, the uncertainty of our DIBH SBRT procedure was sufficient to cover target motion throughout treatment. Based on the target drift value, a maximum of 25 seconds for breath hold time should be employed. Utilizing a tighter gating tolerance of 3 mm SI and 2 mm radially has the potential to maintain target coverage while significantly reducing OAR dose. Aggregated RGPT-derived data may provide optimal treatment planning parameters such as variable uncertainty based on target location.

Dosimetric Planning Comparison for Left-Sided Breast Cancer Radiotherapy: The Clinical Feasibility of Four-Dimensional-Computed Tomography-Based Treatment Planning Optimization.

Background: Adjuvant whole-breast radiotherapy (RT) is a significant part of the standard of care treatment after breast cancer (BC) conserving surgery. Modern techniques including intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) have constituted to better target coverage and critical organs sparing. However, BC survivors are at risk of developing radiation-induced cardiac toxicity. Hence, deep-inspiration breath-hold (DIBH) techniques have been implemented at many centers to further reduce cardiac exposure but require compliance. 4D-CT robust optimization can account for heart intrafractional motion per breathing phase. The optimization has been explored in cardiac sparing of breast IMRT compared to DIBH in a small sample size but has not been evaluated in substructures sparing, nor in VMAT. To provide patients who are not compliant to breath-hold with an optimal treatment approach, various heart sparing techniques need to be evaluated for statistical significance and clinical feasibility.Aim: This retrospective study aimed to provide an extensive dosimetric heart sparing comparison of free-breathing, 4D-CT-based treatment planning, including robust optimization with DIBH-based treatment planning. Combinations of forward and inverse IMRT and VMAT are also considered.Methods: Fifteen early stage left-sided BC standard treatment plans were selected. Breast, lung, left anterior descending artery (LAD), left ventricle (LV), and the whole heart were contoured on each 4D-CT phase and DIBH CT dataset. Each treatment plan was optimized using forward/inverse IMRT and VMAT on the following CT datasets: DIBH, average 4D-CT, and the complete 4D-CT dataset needed for robust optimization. Dose-volume histograms were used to compare V5GyHeart, mean heart dose, mean and max LAD dose, mean LV dose, and V50%Lung.Results: All RT techniques assessed including 4D robust optimization were clinically feasible. Statistically significant differences in mean heart, LAD and LV dose, max LAD dose, and V5GyHeart (p < 0.01) but no difference in V50%Lung (p = 0.29) were found between different techniques. IMRT DIBH achieved the optimal cardiac and substructure sparing among treatment plans. 4D robust IMRT had significantly greater mean heart and LV dose than DIBH IMRT (p ≤ 0.01), except LAD dose. Among free-breathing methods, no difference in all cardiac and substructure dose parameters was observed (p > 0.2) in comparing forward and inverse IMRT with average 4D-CT, inverse average 4D-CT, and 4D robust with IMRT, and between average 4D-CT VMAT and 4D robust VMAT. Only V5GyHeart and mean LV dose were significantly greater in 4D robust VMAT (p < 0.01) compared to DIBH VMAT. Mean heart and LV doses were significantly reduced (p < 0.01) in DIBH IMRT compared to DIBH VMAT. Moreover, mean heart and LV dose, V5GyHeart were significantly reduced in inverse IMRT average 4D-CT compared to average 4D-CT VMAT (p < 0.02) and in 4D robust IMRT compared to 4D robust VMAT (p < 0.04).Conclusion: This study demonstrated the clinical feasibility of 4D robust optimization in limiting the cardiac and substructures dose during free-breathing RT with both IMRT/VMAT for patients who are not compliant with breath-hold RT. However, this study also presents that 4D robust optimization can reduce LAD dose but not fully outperform DIBH or conventional 4D-CT-based planning with IMRT/VMAT in heart sparing in treating early staged left-sided BC patients.

Early Antiarrhythmic Efficacy of Noninvasive Cardiac Radioablation for Ventricular Tachycardia

<h3>Purpose/Objective(s)</h3> Noninvasive cardiac radioablation has been reported to be effective and relatively safe for ventricular tachycardia (VT) in preclinical and clinical studies. However, previous studies implementing cardiac radioablation set a 6-12 weeks of "blanking period" and focused on long-term effects rather than reporting the early changes. In this prospective trial, we focused on the early antiarrhythmic effects within one month after cardiac radioablation. Especially, we tried to seek the differences in response according to the cause of VT. <h3>Materials/Methods</h3> From September 2019 to December 2020, 6 patients (3 ischemic VTs and 3 non-ischemic VTs) were included in this trial and treated with stereotactic body radiotherapy (SBRT) with a single fraction of 25 Gy for intractable VT. A synthesis of imaging studies, 12-lead ECG, and electrophysiological mapping were used to localize the treatment target. The internal target volume was delineated on either maximal intensity projection of 4D-CT or deep inspiration breath hold CT. A 24-hour Holter monitoring was performed for all patients one month before and after SBRT and except for one patient, it was performed from 24 hours before SBRT to 48 hours after SBRT to measure the early response after SBRT. <h3>Results</h3> The number of total ventricular beats decreased by 58% and 60% within 24 hours and 48 hours after SBRT, respectively. It further decreased to 29% of pre-SBRT number of total ventricular beats at one month after SBRT. The decrease of total ventricular beats could be attributed to the decrease of VT burden rather than that of premature ventricular contractions (PVCs) because the burden of VT decreased earlier and more dramatically than that of PVC. After cardiac radioablation, the duration of the longest VT run was shortened. This indicated that cardiac radioablation decreases the VT burden by shortening the durations of VTs. Notably, the cardiac radioablation was more effective for ischemic VTs than non-ischemic VTs in that the VT burden decreased more markedly after SBRT. The electrophysiologic characteristics of VT/PVC were changed after treatment. During one month after SBRT, there was no severe acute toxicity. <h3>Conclusion</h3> In six patients with intractable VT, the noninvasive cardiac radioablation with a dose of 25 Gy was effective even in 1-month follow-up. The decrease of VT burden through shortening of VTs already began within 24 hours after the procedure and continued to decrease until one month after the radioablation. The treatment effect was more remarkable in ischemic than non-ischemic VT patients.

Volumetric arc therapy: A viable option for right-sided breast with comprehensive regional nodal irradiation in conjunction with deep inspiration breath hold

Abstract Purpose Deep inspiration breath hold (DIBH) is an innovative technique routinely used for left-sided breast radiotherapy to significantly reduce harmful dose to the heart and ipsilateral lung. Currently, there is scant literature exploring DIBH for right-sided whole breast and regional nodal irradiation (WB & RNI). The purpose of this study is to examine if DIBH produces a clinically significant reduction in organ at risk (OAR) dose for right-sided WB + RNI, whilst comparatively analysing the use of volumetric arc therapy (VMAT) versus tangential inverse modulated radiotherapy (t-IMRT). Methods and Materials Ten patients, previously treated for left sided breast cancer (with a FB and DIBH CT scan), were selected from our database to be retrospectively replanned to the right breast and nodal regions. Planning target volumes (PTV) were marked to include the whole right breast and regional nodes, encompassing the supraclavicular fossa (SCF) and internal mammary nodes (IMN). PTVs and OARs were contoured on the Pinnacle workstation according to the Radiation Therapy Oncology Group (RTOG) guidelines. VMAT and t-IMRT plans were generated to a prescribed dose of 50 Gy in 25 fractions on both the DIBH and FB data sets for dosimetric analysis. Results Coverage of the right breast (mean, D95%) and SCF (D95%) were significantly improved with VMAT in comparison to t-IMRT, with no statistically significant variation on the IMN PTV (D95%). The use of DIBH did not impact PTV coverage compared with FB. VMAT reduced dose to the ipsilateral lung (mean, V20Gy), combined lungs (mean, V20Gy) and liver (D2cc); conversely dose to the heart (mean), left lung (mean, V5Gy) and contralateral breast (mean) were increased. For both techniques DIBH significantly improved dose to OARs including the ipsilateral lung (mean, V20Gy, V5Gy), total lung (mean, V20Gy), heart (mean, V25Gy) and liver (D2cc) when compared to FB. Conclusion DIBH could be considered for patients treated with right-sided WB and RNI due to a significant decrease in heart, ipsilateral lung, total lung and liver doses. VMAT significantly improves PTV coverage over t-IMRT whilst reducing dose to the ipsilateral lung and liver, albeit to the detriment of the left lung, contralateral breast and heart. The increase in heart dose can be mitigated by the use of DIBH. We recommend if VMAT is utilised for superior target volume coverage, DIBH should also be implemented to reduce OAR toxicity.

Early Experiences of Deep Inspiration Breath Hold Technique in Stereotactic Body Radiotherapy for Localized Lung Tumor

Organ motion management in stereotactic body radiotherapy (SBRT) for localized lung tumor is key for a successful treatment delivery. We would like to describe our limited clinical experiences of deep inspiration breath hold (DIBH) technique in stereotactic body radiotherapy for localized lung tumor and compare the dosimetric results with free breathing (FB) technique. Five patients with Tumor Staging T1 – T2 N0 M0 (Size < 5.0 cm) with peripheral lesion were treated with DIBH-SBRT were included in this study. All the five patients under went CT simulation using DIBH and 4D-CT for FB techniques. Plans were created using two to three coplanar modulated partial arcs using 10MV flattening filter free (FFF) bream with a dose rate of 2400 MU/min in both FB and DIBH CT data sets using True Beam Linear accelerator. Same dose constraints for the target and the critical structures for a particular patient were used during the plan optimization process in DIBH and FB datasets. All the patients received 50 Gy in 5 fractions (BED10 100 Gy10) for all the patients using DIBH CT dataset on the other hand FB data set plans were only used for dosimetric comparisons. Daily gated DIBH cone-beam CT were performed for all the patients during treatment delivery. For standardization, all the plans were normalized at target mean of the planning target volume (PTV). Doses to the critical structures and targets were recorded from the dose volume histogram for evaluation. The overall survival (OS) and local control (LC) and toxicity assessment were documented during the follow-up. In spite of our small sample size, there is a strong evidence that DIBH-SBRT plans were far superior to the FB-SBRT plans. The mean age of all the patients is 65.2 years (range 55 to 78 years) with a mean follow-up of 24.2 months (range 10 to 32 months). Out of five patients, four patients are still alive with complete remission of disease and one patient died after 10 months due to septicemia during blood transfusion. No grade 3 acute and late toxicity were documented during treatment and follow-up. The mean right and left lung volumes were inflated by 1.55 and 1.60 times in DIBH scans compared to the FB scans. The mean internal target volume (ITV) increased in the FB datasets by 1.45 times compared to the DIBH data sets. The mean dose followed by standard deviation (x̄ ± sx̄) of ipsilateral lung for DIBH-SBRT and FB-SBRT plans were 7.48 ± 3.57 (Gy) and 10.23 ± 4.58 (Gy) respectively, with a mean reduction of 36.84% in DIBH-SBRT plans. Ipsilateral lung was reduced to 36.84% in DIBH plans compared to FB plans. Significant dose reduction in ipsilateral lung due to the lung inflation and target volume reduction due to motion restriction in DIBH-SBRT plans were observed compare to FB-SBRT. DIBH-SBRT plans demonstrate superior dose reduction to the normal tissues and other critical structures. DIBH-SBRT provides us simpler and safer organ motion management in the treatment of localized lung tumor.

Cardiac Sparing with Personalized Treatment Planning for Early-stage Left Breast Cancer.

PurposeTo compare cardiac doses of different whole-breast optimization schemes including free-breathing (FB) tangential radiotherapy (TRT), deep-inspiration breath-hold (DIBH) TRT, and FB helical tomotherapy (HT).MethodsEarly-stage left-sided breast cancer patients who underwent breast-conserving surgery followed by adjuvant radiotherapy were included in the study. Planning images included FB and DIBH CT scans acquired in the same supine treatment position with both arms abducted. A hypofractionated regimen of 42.5 Gy in 16 fractions was used. Clinical target volume delineation was aided through the use of a radio-opaque wire. A 7-mm margin was used in generating the planning target volumes. TRT plans were generated both in FB and DIBH. For the FB tomotherapy technique, a first plan (Tomo 1) was optimized limiting the maximum contralateral breast dose to 3.1 Gy. A second tomotherapy plan (Tomo 2) focused on the reduction of the mean heart dose without controlling the contralateral breast dose. All plans were optimized to obtain an equivalent planning target volume (PTV) coverage of ≥95% of the prescribed dose while minimizing the dose to organs at risk.ResultsTwenty-three patients treated between October 2012 and March 2016 were included in this retrospective study. Eleven patients (48%) had at least one major cardiovascular risk factors including one patient (4%) with a history of myocardial infarction. Six patients (26%) had been exposed to cardiotoxic chemotherapy agents. The average mean dose to the heart was 3.1 Gy with FB TRT, 1.1 with DIBH TRT, 2.4 Gy for Tomo 1, and 1.5 Gy for Tomo 2. The mean dose to the left anterior descending artery was 27.0 Gy, 8.0 Gy, 13.7 Gy and 6.6 Gy for FB TRT, DIBH TRT, Tomo 1 and Tomo 2 plans respectively.ConclusionDifferent cardiac-sparing optimization schemes are possible when treating left breast cancer. Although DIBH offers clear mean heart dose reductions, tomotherapy can be an interesting alternative treatment modality to spare the heart and coronary vessels, notably in patients who cannot comply with DIBH.

6. Deep Inspiration Breath Hold of Left-sided Breast cancer radiotherapy: predictive parameters for patient selection

Purpose To investigate possible predictive anatomical features correlating to cardiac and left-lung dose sparing by deep inspiration breathhold (DIBH) technique compared to freebreathing (FB) for left-sided whole breast radiation therapy (RT). Materials and Methods Twenty consecutive patients who underwent (DIBH) left-sided breast RT had both FB and DIBH CT simulation. All patients were planned with two 6 MV-flattening-filter-free FFF (DIHB) and two/four (FB) 6 MV IMRT tangential fields, with prescription of 50 Gy/25 fr to whole breast and 60 Gy to simultaneous integrated boost (SIB). Mean dose and dosevolume metrics (V5Gy, V10Gy, V20Gy) were analyzed and compared for heart and left-lung for both FB and DIBH techniques. Correlation analyses were performed between such dose metrics and patient (FB) anatomic features: maximal heart distance and length (MHD, MHL), maximal lung distance (MLD), chest wall rise (CWH) (Fig. 1). Paired t-test or Wilcoxon signed-rank test was applied to compare differences in the dose metrics between the two techniques and linear regression was used for data analysis with significance level of p ≤ 0.05. Results All dose metrics for the heart and left-lung were significantly reduced (p Conclusion In this patient cohort, DIBH technique has been shown to reduce dose to the heart and left-lung. MHL(FB) and CWH served as significant predictors for heart and left-lung dose sparing by DIBH. These parameters can be easily measured at the time of CT simulation and thus may be used as simple and quick tool to determine which patient may benefit from a DIBH technique.

Dosimetric Comparison of Deep Inspiration Breath-Hold versus Free Breathing for Right-Sided Breast Cancer with Comprehensive Nodal Radiation

Patients undergoing radiation for breast cancer are at risk of long-term cardiac morbidity and radiation-related coronary artery disease, which is correlated with dose to the heart. Deep inspiration breath-hold (DIBH) technique reduces dose to organs at risk for patients undergoing left breast radiation. The role of DIBH in reducing dose to coronaries, heart, and lungs for right-sided breast cancers is less clear. We evaluated whether treatment planning using DIBH produces significant reduction in right coronary artery (RCA), heart, and lung dose as compared to free breathing (FB) for patients receiving radiation to the breast and regional lymph nodes lymph nodes for right-sided breast cancer. We compared 8 consecutive right-sided breast cancer patients planned with modified wide tangent plans to cover the breast, levels I-III of the axilla, and supraclavicular and internal mammary lymph nodes on paired DIBH and FB CT scans. Lymph nodes were contoured according to the RTOG atlas. RCA was contoured according to the RADCOMP breast atlas available on the RTOG website. All patients were planned to receive 50 Gy in 25 fractions. We compared dose-volume data for DIBH versus FB for RCA, heart, right lung, and total lung. Plan metrics were compared using Wilcoxon signed-rank testing on SPSS. DIBH significantly decreased RCA mean dose, heart maximum point dose, mean heart dose, and heart V5 (Table 1). The difference in maximum point dose and V5 for RCA approached statistical significance (p=0.063 and 0.068, respectively). Mean lung dose for the right lung and total lung were significantly improved with DIBH, as were V20 for the right lung and total lung (Table 1). DIBH resulted in a significantly decreased RCA mean dose as well as a decrease in multiple cardiac and lung dose metrics. DIBH should be considered for right-sided breast cancer patients undergoing radiation to the breast and regional lymph nodes via partial wide tangents.Abstract TU_11_3432: Table 1Organ at risk dose-volume comparison between FB versus DIBHFB MeanBH Meanp-valueRCA D(0.03cc) (cGy)1199333.063RCA D(mean) (cGy)251140.025RCA V5(%)6.80.068Heart D(0.03cc) (cGy)1710552.036Heart D(mean) (cGy)9356.012Heart V5 (%)20.027Right Lung D(mean) (cGy)15241202.036Total Lung D(mean) (cGy)886678.036Right Lung V20 (%)3124.025Total Lung V20 (%)1813.025 Open table in a new tab

Set-up Reproducibility for Deep Inspiration Breath Hold for Left Sided Breast Cancer Treatment Using Daily Mega Voltage Imaging-Integrated Network Study

Deep inspiration breath hold (DIBH) technique has been effective to reduce cardiac dose for left sided breast cancer treatment. However there are limited data on the setup reproducibility with DIBH technique. Herein we report the daily setup reproducibility and variation of DIBH using daily mega voltage (MV) imaging based on a large network of data. In total, 109 left breast cancer patients from 10 hospital sites across the UPMC Hillman Cancer Center network were treated using DIBH technique with daily MV imaging from May 2016 to July 2017. All patients had visual coaching via iPod device as well as voice coaching for DIBH for CT simulation and treatment. The same procedure and technique for DIBH CT simulation and treatment planning have been shared between physicists and physicians across the network. For each patient, BMI, age, surgery type (lumpectomy or mastectomy), regional and internal mammary nodes (IMN) involvement, MV imaging procedure used, number of total portal images and inter-fraction directional shifts were collected. For the statistical analyses, we separated all patients into two groups in each of the following three categories; 1) obese (BMI ≥ 30) vs. non- obese, 2) surgery type: mastectomy vs. lumpectomy, 3) internal mammary node (IMN) treatment vs. no IMN treatment. A total of 1833 treatments and 2818 MV portal images were analyzed. Minimum mean distance from heart to the tangential field edge was 2.5 mm (ranges 0-12 mm). The group mean inter-fraction directional shifts were as following: 1) 0.7 mm (superior; SD = 2.26), 0.8 mm (inferior; SD = 2.21), 2) 0.65 mm (left; SD =1.60), 0.64 mm (right; SD = 1.62), 3) 0.89 mm (anterior; SD = 1.96), 0.83 mm (posterior; SD=2.03). However between hospitals, there was found a difference in mean inter-fraction directional shift (p < 0.001). Any inter-fraction directional shift for ≥ 2mm, ≥ 3mm, ≥ 4mm, ≥ 5mm, ≥ 10mm was found to be 52.9 %, 37.6 %, 30.9 %, 21.9 %, 3.7 % of total fractions, respectively. In the stratified analysis, obese patients had larger directional shifts (p < 0.05) and highly associated with number of fractions for ≥ 5mm in any directional shift compared to non-obese patients (29 % vs. 17 %; p =0.04). To the best of our knowledge, this is the first and the largest study that reports the daily setup reproducibility and variation using MV images and patient’s visual feedback. DIBH setup for left breast cancer treatment at our large cancer center network was reproducible with any mean directional shifts less than 1.0 mm, although there was some inter-fraction variation between hospital sites. Consideration of daily imaging for obese patients should be taken to ensure the benefit of DIBH for that population. Also, if the distance of heart to the edge of the tangential treatment field is relatively close, it would be more beneficial to have daily imaging because 53 % of patients still had ≥ 2 mm shift.

Reduction in low-dose to normal tissue with the addition of deep inspiration breath hold (DIBH) to volumetric modulated arc therapy (VMAT) in breast cancer patients with implant reconstruction receiving regional nodal irradiation

BackgroundDespite dosimetric benefits of volumetric modulated arc therapy (VMAT) in breast cancer patients with implant reconstruction receiving regional nodal irradiation (RNI), low dose to the thoracic structures remains a concern. Our goal was to report dosimetric effects of adding deep inspiration breath hold (DIBH) to VMAT in left-sided breast cancer patients with tissue expander (TE)/permanent implant (PI) reconstruction receiving RNI.MethodsTen consecutive breast cancer patients with unilateral or bilateral TE/PI reconstruction who were treated with a combination of VMAT and DIBH to the left reconstructed chest wall and regional nodes were prospectively identified. Free breathing (FB) and DIBH CT scans were acquired for each patient. VMAT plans for the same arc geometry were compared for FB versus DIBH. Prescription dose was 50 Gy in 25 fractions. Dosimetric differences were tested for statistical significance.ResultsFor comparable coverage and target dose homogeneity, the mean dose to the heart reduced on average by 2.9 Gy (8.2 to 5.3 Gy), with the addition of DIBH (p < 0.05). The maximum dose to the left anterior descending (LAD) artery was reduced by 9.9 Gy (p < 0.05), which related closely to the reduction in the maximum heart dose (9.4 Gy). V05 Gy to the heart, ipsilateral lung, contralateral lung and total lung (p < 0.05) decreased on average by 29.6%, 5.8%, 15.4% and 10.8% respectively. No significant differences were seen in the ipsilateral lung V20 Gy or mean dose as well as in the mean contralateral breast/implant dose. However, V04 Gy and V03 Gy of the contralateral breast/implant were respectively reduced by 13.2% and 18.3% using DIBH (p < 0.05).ConclusionCombination of VMAT and DIBH showed significant dosimetric gains for low dose to the heart, lungs and contralateral breast/implant. Not surprisingly, the mean and maximum dose to the heart and to the LAD were also reduced. DIBH should be considered with the use of VMAT in breast cancer patients with implant reconstructions receiving RNI.

Comparison of cardiac and lung doses for breast cancer patients with free breathing and deep inspiration breath hold technique in 3 dimensional conformal radiotherapy - a dosimetric study

Abstract Purpose: To investigate the cardio-pulmonary doses between Deep Inspiration Breath Hold (DIBH) and Free Breathing (FB) technique in left sided breast irradiation. Materials &amp; Methods: DIBH CT and FB CT were acquired for 10 left sided breast patients who underwent whole breast irradiation with or without nodal irradiation. Three fields single isocenter technique were used for patients with node positive patients along with two tangential conformal fields whereas only two tangential fields were used in node negative patients. All the critical structures like lungs, heart, esophagus, thyroid, etc., were delineated in both DIBH and FB scan. Both DIBH and FB scans were fused with the Dicom origin as they were acquired with the same Dicom coordinates. Plans were created in the DIBH scan for a dose range between 50 Gy in 25 fractions. Critical structures doses were recorded from the Dose Volume Histogram for both the DIBH and FB data set for evaluation. Results: The average mean heart dose in DIBH vs FB was 13.18 Gy vs 6.97 Gy, (p = 0.0063) significantly with DIBH as compared to FB technique. The relative reduction in average mean heart dose was 47.12%. The relative V5 reduced by 14.70% (i.e. 34.42% vs 19.72%, p = 0.0080), V10 reduced by 13.83% (i.e. 27.79 % vs 13.96%, p = 0.0073). V20 reduced by 13.19% (i.e. 24.54 % vs 11.35%, p = 0.0069), V30 reduced by 12.38% (i.e. 22.27 % vs 9.89 %, p = 0.0073) significantly with DIBH as compared to FB. The average mean left lung dose reduced marginally by 1.43 Gy (13.73 Gy vs 12.30 Gy, p = 0.4599) but insignificantly with DIBH as compared to FB. Other left lung parameters (V5, V10, V20 and V30) shows marginal decreases in DIBH plans compare to FB plans. Conclusion: DIBH shows a substantial reduction of cardiac doses but slight and insignificant reduction of pulmonary doses as compared with FB technique. Using the simple DIBH technique, we can effectively reduce the cardiac morbidity and at the same time radiation induced lung pneumonitis is unlikely to increase.

Postmastectomy Radiation Therapy Technique and Cardiopulmonary Sparing: A Dosimetric Comparative Analysis Between Photons and Protons With and Without Deep Inspiration Breath Hold

Post-mastectomy radiation therapy (PMRT) can be challenging in patients with left-sided disease due to significant risk of cardiopulmonary toxicity. Prior dosimetric studies have suggested greater cardiopulmonary sparing with protons over tangential photons for left-sided PMRT. However, modern techniques, such as deep inspiration breath hold (DIBH), can help spare the heart. This analysis compares photon and proton delivery with and without DIBH. Ten women with left breast cancer referred for PMRT on a prospective clinical trial underwent free breathing (FB) and DIBH CT simulation. Target volumes and cardiopulmonary organs-at-risk were delineated with assistance of the RTOG atlas by a single physician. Structures were contoured on the FB scan and transferred to the DIBH scan using MimVista deformable registration and modified. A partially wide tangent (PWTF) during DIBH (photon-BH), passively scattered proton during FB (scatter-FB), pencil-beam scanning (PBS) proton during FB (PBS-FB), and PBS proton during DIBH (PBS-BH) plan was completed for each patient. Each plan was designed to achieve 95% prescription dose coverage of 95% of all target volumes while maximally sparing the heart and lung. ANOVA or Kruskal-Wallis test was used to measure a difference in target volume coverage, chest wall homogeneity index (HI), and cardiopulmonary avoidance among the four plans. For each metric with a significant interaction (P < 0.05), pairwise t-test and Wilcoxon test with Bonferroni correction was used to compare individual plans. All techniques resulted in similar target coverage, though protons improved chest wall HI and cardiopulmonary sparing (omnibus P < 0.0001 for each metric). Heart/lung metrics for photon-BH, scatter-FB, PBS-FB, and PBS-BH, respectively, were as follows: mean heart dose (2.09, 0.39, 0.98, 0.71 Gy(RBE)), mean left ventricle dose (3.72, 0.08, 0.19, 0.21 Gy(RBE)), V20 left ventricle (2.73, 0.03, 0, 0%), maximum LAD artery dose (46.14, 8.28, 4.58, 4.63 Gy(RBE)), mean lung dose (13.30, 5.74, 7.63, 7.49 Gy(RBE)), V20 lung (26.04, 12.04, 15.18, 14.43 %). Pairwise testing confirmed an improvement in each metric with all proton plans compared to photon-BH; however, there were no differences in HI or cardiopulmonary sparing between passively scattered and PBS protons, regardless of addition of DIBH. For left-sided PMRT, passively scattered or PBS protons with or without DIBH improves homogeneity and cardiopulmonary sparing without compromise in target coverage compared to PWTF photons with DIBH. Furthermore, the addition of DIBH to proton therapy did not provide a significant dosimetric benefit.

An effective deep-inspiration breath-hold radiotherapy technique for left-breast cancer: impact of post-mastectomy treatment, nodal coverage, and dose schedule on organs at risk.

BackgroundWe developed, applied, and prospectively evaluated a novel deep-inspiration breath-hold (DIBH) screening and delivery technique to optimize cardiac sparing in left-breast radiotherapy (RT) at our clinic. The impact of set-up and dose variables upon organs at risk (OAR) dose in DIBH RT was investigated.Methods and materialsAll patients with left-breast cancer referred between 2011 and 2014 – of all disease stages, set-up variations, and dose prescriptions – were included. Radiographers used simple screening criteria at CT simulation, to systematically assess patients for obvious DIBH benefit and capability. Selected patients received forward-planned intensity-modulated RT (IMRT) based on a DIBH CT scan. A 3D-surface monitoring system with visual feedback assured reproducible DIBH positioning during gated radiation delivery. Patient, target set-up, and OAR dose information were collected at treatment.ResultsOf 272 patients who were screened, 4 withdrew, 56 showed no obvious advantage, and 56 showed benefit but had suitability issues; 156 patients were selected and successfully completed DIBH treatment. The technique was compatible with complex set-up and optimal target coverage was maintained. Comparison of free-breathing (FB) and DIBH treatment plans in the first five patients enrolled confirmed DIBH reduced heart radiation by ~80% (p = 0.032). Low OAR doses were achieved overall: the mean (95% confidence interval [CI]) heart dose was 1.17 (1.12–1.22) Gy, and the mean ipsilateral lung dose was 5.26 (5.01–5.52) Gy. Patients who underwent a standard radiation schedule (40 Gy/15#) after breast-conserving surgery had the lowest OAR doses: post-mastectomy treatment, simultaneous supraclavicular (SCV) node coverage, and alternative dose schedule (50 Gy/25#) were interrelated variables associated with increased OAR risk and compromised ipsilateral lung dose constraints.ConclusionThe DIBH technique was successfully implemented and resulted in optimally low heart radiation. All patients who demonstrate sufficient DIBH technique at planning CT are now offered DIBH RT at our clinic. Patients with more advanced disease, particularly those with additional pulmonary risk factors, warrant additional focus to improve lung sparing.

Deep inspiration breath-hold radiotherapy for lung cancer: impact on image quality and registration uncertainty in cone beam CT image guidance

We investigated the impact of deep inspiration breath-hold (DIBH) and tumour baseline shifts on image quality and registration uncertainty in image-guided DIBH radiotherapy (RT) for locally advanced lung cancer. Patients treated with daily cone beam CT (CBCT)-guided free-breathing (FB) RT had an additional CBCT in DIBH at three fractions. These CBCT scans were offline rigidly registered (on tumour) to FB and DIBH CT scans acquired at planning. All registrations were repeated to evaluate the intraobserver uncertainty. CBCT scans were scored on degree of streak artefacts and visualization of tumour and anatomical structures. We examined the impact of tumour baseline shift between consecutive DIBHs on CBCT image quality. CBCT scans from 15 patients were analysed. Intraobserver image registration uncertainty was approximately 2 mm in both FB and DIBH, except for the craniocaudal direction in FB, where it was >3 mm. On the 31st fraction, the intraobserver uncertainty increased compared with the second fraction. This increase was more pronounced in FB. Image quality scores improved in DIBH compared with FB for all parameters in all patients. Simulated tumour baseline shifts ≤2 mm did not affect the CBCT image quality considerably. DIBH CBCT improved image quality and reduced registration uncertainty in the craniocaudal direction in image-guided RT of locally advanced lung cancer. Baseline shifts ≤2 mm in DIBH during CBCT acquisition did not affect image quality. Advances in knowledge: DIBH RT has dosimetric advantages over FB; this work demonstrates an additional benefit of DIBH in terms of registration accuracy because of improved image quality.

Deep inspiration breath-hold produces a clinically meaningful reduction in ipsilateral lung dose during locoregional radiation therapy for some women with right-sided breast cancer

PurposeThe goal of the work described here was to determine whether deep inspiration breath-hold (DIBH) produces a clinically meaningful reduction in pulmonary dose compared with free breathing (FB) during locoregional radiation for right-sided breast cancer. Methods and materialsFour-field, modified-wide tangent plans with full nodal coverage were developed for 30 consecutive patients on paired DIBH and FB CT scans. Nodes were contoured according to European Society for Radiotherapy and Oncology guidelines. Plan metrics were compared using Wilcoxon signed-rank testing. ResultsIn 21 patients (70%), there was a ≥5% reduction in ipsilateral lung V20Gy with DIBH compared with FB. The mean decrease in ipsilateral lung V20Gy was 7.8% (0%-20%, P < .001). The mean lung dose decreased on average by 3.4 Gy with DIBH (–0.2 to 9.1, P < .001). The mean reduction in liver volume receiving 50% of the prescribed dose was 42.3 cm3 (0-178.9 cm3, P < .001). ConclusionsDIBH reduced ipsilateral lung V20Gy by ≥5% in the majority of patients. For some patients, the volume of liver receiving a potentially toxic dose decreased with DIBH. DIBH should be available as a treatment strategy to reduce ipsilateral lung V20Gy prior to compromising internal mammary chain nodal coverage for patients with right-sided breast cancer during locoregional radiation therapy if the V20Gy on FB exceeds 30%.

Advantage of deep inspiration breath hold in left-sided breast cancer patients treated with 3D conformal radiotherapy.

To compare 3D-conformal radiotherapy (3D-CRT) treatment plans based on free-breathing (FB) and deep inspiration breath hold (DIBH) and investigated whether DIBH technique enables a decrease of cardiac left anterior descending coronary artery (LADCA) and lungs dose with respect to the FB. Twenty-three left-sided breast cancer patients referred for breast radiotherapy were included. The planning target volume (PTV) encompassed the breast and organs at risk including heart, LADCA, lungs, and contralateral breast, which were contoured in FB and DIBH CT scans. Dose to PTV was 50 Gy in 25 fractions. Two treatment plans were generated for each patient: FB-3D-CRT and DIBH-3D-CRT. Dosimetry parameters were obtained from dose volume histograms. Data were compared using the paired-sample Wilcoxon signed rank test. For heart, LADCA, and left lung, a significant dose reduction was found using DIBH technique. By using DIBH, an average reduction of 25% was observed in LADCA for the volume receiving 20 Gy and of 48% considering the mean heart dose. The DIBH technique results in a significant decrease of dose to the heart, LADCA, and left lung compared to FB.

SU‐F‐J‐123: CT‐Based Determination of DIBH Variability and Its Dosimetric Impact On Post‐Mastectomy Plus Regional Nodal Radiation Therapy

Purpose:Breast cancer radiotherapy delivered using voluntary deep inspiration breath‐hold (DIBH) requires reproducible breath holds, particularly when matching supraclavicular fields to tangential fields. We studied the impact of variation in DIBHs on CTV and OAR dose metrics by comparing the dose distribution computed on two DIBH CT scans taken at the time of simulation.Methods:Ten patients receiving 50Gy in 25 fractions to the left chestwall and regional lymph nodes were studied. Two simulation CT scans were taken during separate DIBHs along with a free‐breathing (FB) scan. The treatment was planned using one DIBH CT. The dose was recomputed on the other two scans using adaptive planning (Pinnacle 9.10) in which the scans are registered using a cross‐correlation algorithm. The chestwall, lymph nodes and OARs were contoured on the scans following the RTOG consensus guidelines. The overall translational and rotational variation between the DIBH scans was used to estimate positional variation between breath‐holds. Dose metrics between plans were compared using paired t‐tests (p &lt; 0.05) and means and standard deviations were reported.Results:The registration parameters were sub‐millimeter and sub‐degree. Although DIBH significantly reduced mean heart dose by 2.4Gy compared to FB (p &lt; 0.01), no significant changes in dose were observed for targets or OARs between the two DIBH scans. Nodal coverage as assessed by V90% was 90%±8% and 89%±8% for supraclavicular and 99%±2% and 97%±22% for IM nodes. Though a significant decrease (10.5%±12.4%) in lung volume in the second DIBH CT was observed, the lung V20Gy was unchanged (14±2% and 14±3%) between the two DIBH scans.Conclusion:While the lung volume often varied between DIBHs, the CTV and OAR dose metrics were largely unchanged. This indicates that manual DIBH has the potential to provide consistent dose delivery to the chestwall and regional nodes targets when using matched fields.