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

Abstract

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 < 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 < 0.01), no significant changes in dosemore » 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.« less

Authors:
; ; ; ; ;  [1]
  1. The University of Chicago, Chicago, IL (United States)
Publication Date:
OSTI Identifier:
22634728
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ALGORITHMS; COMPARATIVE EVALUATIONS; COMPUTERIZED TOMOGRAPHY; CORRELATIONS; HEART; IMAGE PROCESSING; LUNGS; LYMPH; LYMPH NODES; MAMMARY GLANDS; NEOPLASMS; PATIENTS; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOTHERAPY; RECOMMENDATIONS; RESPIRATION; SIMULATION

Citation Formats

Malin, M, Kang, H, Tatebe, K, Hasan, Y, Chmura, S, and Al-Hallaq, H. SU-F-J-123: CT-Based Determination of DIBH Variability and Its Dosimetric Impact On Post-Mastectomy Plus Regional Nodal Radiation Therapy. United States: N. p., 2016. Web. doi:10.1118/1.4956031.
Malin, M, Kang, H, Tatebe, K, Hasan, Y, Chmura, S, & Al-Hallaq, H. SU-F-J-123: CT-Based Determination of DIBH Variability and Its Dosimetric Impact On Post-Mastectomy Plus Regional Nodal Radiation Therapy. United States. doi:10.1118/1.4956031.
Malin, M, Kang, H, Tatebe, K, Hasan, Y, Chmura, S, and Al-Hallaq, H. 2016. "SU-F-J-123: CT-Based Determination of DIBH Variability and Its Dosimetric Impact On Post-Mastectomy Plus Regional Nodal Radiation Therapy". United States. doi:10.1118/1.4956031.
@article{osti_22634728,
title = {SU-F-J-123: CT-Based Determination of DIBH Variability and Its Dosimetric Impact On Post-Mastectomy Plus Regional Nodal Radiation Therapy},
author = {Malin, M and Kang, H and Tatebe, K and Hasan, Y and Chmura, S and Al-Hallaq, H},
abstractNote = {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 < 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 < 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.},
doi = {10.1118/1.4956031},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Objective: To assess the impact of radiation management on male breast cancer (MBC) at London Regional Cancer Program (LRCP). Methods and Materials: Men with a diagnosis of breast cancer referred to LRCP were reviewed. The seventh American Joint Committee on Cancer staging system was used. Patients treated with and without post-mastectomy radiation therapy (PMRT) were analyzed. Disease-free survival (DFS) was defined as time duration from diagnosis to first recurrence. Overall survival (OS) was defined as time duration from pathologic diagnosis to death or last follow-up with any death defined as an event. Survival estimates were obtained using Kaplan-Meier methodology. Results:more » From January 1977 to December 2006, 81 men had invasive ductal carcinoma. The median age was 65 (range, 35-87 years). There were 15 Stage I, 40 Stage II, 20 Stage III, and 6 Stage IV patients. Median follow-up time was 46 months (range, 1-225 months). Of the 75 patients treated with curative intent, 29 did not receive PMRT and 46 completed PMRT. Patients who received PMRT demonstrated no benefit in overall survival (p = 0.872) but significantly better local recurrence free survival (p < 0.001) compared with those who did not receive RT. There was trend toward improving locoregional recurrence with PMRT in patients with high-risk features (node-positive, advanced stage, and {<=}2 mm or unknown surgical margin). The median, 5-year, and 10-year disease-free survival and overall survival for the 75 patients were 77.7 months, 66.3%, 32.7%, and 91.2 months, 73.9%, and 36.6%, respectively. Conclusion: The experience at LRCP suggests that high-risk MBC patients should consider PMRT to improve their chance of local recurrence-free survival.« less
  • No abstract prepared.
  • Purpose: Patients undergoing radiotherapy (RT) for left-sided breast cancer have increased risk of coronary artery disease. Deep Inhalation Breath Hold assisted RT (DIBH-RT) is shown to increase the geometric separation of the target area and heart, reducing cardiac radiation dose. The purposes of this study are to use Cine MV portal images to determine the stability of spirometer-guided DIBH-RT and examine the dosimetric cardiopulmonary impact of this technique. Methods: Twenty consecutive patients with left-sided breast cancer were recruited to the IRB-approved study. Free-breathing (FB) and DIBH-CT's were acquired at simulation. Rigid registration of the FB-CT and DIBH-CT was performed usingmore » primarily breast tissue. Treatment plans were created for each FB-CT and DIBH-CT using identical paired tangent fields with field-in-field or electronic compensation techniques. Dosimetric evaluation included mean and maximum (Dmax) doses for the left anterior descending artery (LAD), mean heart dose, and left lung V20. Cine MV portal images were acquired for medial and lateral fields during treatment. Analysis of Cine images involved chest wall segmentation using an algorithm developed in-house. Intra- and inter-fractional chest wall motion were determined through affine registration to the first frame of each Cine. Results: Dose to each cardiac structure evaluated was significantly (p<0.001) reduced with the DIBH plans. Mean heart dose decreased from 2.9(0.9–6.6) to 1.6(0.6–5.3) Gy; mean LAD dose from 16.6(3–43.6) to 7.4(1.7–32.7) Gy; and LAD Dmax from 35.4 (6.1–53) to 18.4(2.5–51.2) Gy. No statistically significant reduction was found for the left lung V20. Average AP and SI median chest wall motion (intrafractional) was 0.1 (SD=0.9) and 0.5 (SD=1.1) mm, respectively. Average AP inter-fractional chest wall motion was 2.0 (SD=1.4) mm. Conclusion: Spirometer-based DIBH treatments of the left breast are reproducible both inter- and intra-fractionally, and provide a statistically and potentially clinically useful dosimetric advantage to cardiac structures.« less
  • Purpose: In the era of dose escalation and numerous protocols evaluating radiation delivery to the prostate, it is imperative to achieve accurate and standardized daily set up. At the Sylvester Comprehensive Cancer Center, patients are instructed to drink 8 ounces of water 30 minutes prior to RT and follow a low residue diet to ensure that the anorectum is not distended and the bladder is adequately filled. If daily CBCT imaging shows any variation, the patient is removed from the table and drinks water or evacuates their rectum prior to a repeat CBCT. Here we attempt to quantify the efficacymore » of this procedure. Methods: CBCTs were collected for 5 patients receiving 40 fractions of definitive treatment for prostate cancer. CBCTs were imported into MIM (v6.5.7, Cleveland OH) and the bladder, anorectum, and prostate were contoured. Using the daily registration reviewed by the attending physician, the planning dose was rigidly transferred to the daily CBCT. On days that multiple CBCTs were performed due to inadequate anorectum or bladder preparation, the repeated and final CBCTs were evaluated for variations in V40Gy and V65Gy to both the anorectum and bladder. Results: A high level of variability in doses to the anorectum and bladder was found in the scans that were not utilized for treatment. The aggregate lower quartile for the unused versus used CBCTs was 27.2% vs. 16.83% for V40Gy and 8.53% vs. 5.66% for V65Gy bladder. The upper quartiles showed to be 48.88% vs. 41.92% and 21.05% vs. 20.55%. The combined lower quartile for the unused vs. used CBCTs was 8.24% vs. 5.49% for V40Gy and 0.57% vs. 0.0% for V65Gy anorectum. The upper quartiles were 34.35% vs. 33.25% and 18.37% vs. 16.11%. Conclusion: This study shows that daily imaging is insufficient and that proper bladder and anorectum preparation are essential to deliver proper treatment.« less
  • The purpose of this work was to determine the risk of local-regional failure following post-mastectomy radiotherapy and the incidence of complications associated with such treatment. The authors retrospectively analyzed the results in 309 patients with Stage I--III invasive breast cancer treated with post-mastectomy radiation therapy between 1975 and 1985. The median radiotherapy dose was 45 Gy in 1.8 to 2.25 Gy fractions. One hundred forty-seven (48%) of the patients received adjuvant systemic chemotherapy with 115 (78%) of these receiving a CMF-based or doxorubicin-containing regime. The median follow-up time of surviving patients was 130 months (range, 28 to 191 months) aftermore » mastectomy. Seventeen patients (6%) developed a local-regional failure at an interval of 4 to 87 months after radiotherapy. Moderate or severe complications related to radiotherapy and requiring treatment were uncommon. Symptomatic radiation pneumonitis occurred in four patients (1.3%), arm edema in 18 (5.8%), and brachial plexopathy in 2 (0.6%). The authors conclude that post-operative radiotherapy is a safe and effective means of reducing local-regional failure following mastectomy. The efficacy of post-mastectomy radiotherapy in improving survival should be addressed in new large randomized controlled studies. 33 refs., 1 fig., 3 tabs.« less