Madeera Kathpal1, Brent Tinnel2, Kelly Sun3, Stephanie Ninneman4, Cynthia Malmer5, Stacie Wendt4, Sheena Buff2, David Valentich2, Marisa Gossweiler6, Dusten Macdonald7. 1. Department of Radiation Oncology, Fort Belvoir Community Hospital, Fort Belvoir, Virginia. 2. Department of Radiation Oncology, Madigan Army Medical Center, Tacoma, Washington. 3. F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland. 4. The Geneva Foundation, Tacoma, Washington. 5. Northwest Medical Physics Center, Lynwood, Washington. 6. Department of Radiology, Madigan Army Medical Center, Tacoma, Washington. 7. Department of Radiation Oncology, Madigan Army Medical Center, Tacoma, Washington. Electronic address: dusten.m.macdonald.mil@mail.mil.
Abstract
PURPOSE: With most patients now living long after their breast cancer diagnosis, minimizing long-term side effects of breast cancer treatment, such as reducing late cardiac and pulmonary side effects of radiation therapy (RT), is particularly important. It is now possible to use an electromagnetic tracking system to allow real-time tracking of chest wall (CW) position during the delivery of RT. Here, we report our experience using electromagnetic surface transponders as an added measure of CW position during deep inspiration breath hold (DIBH). METHODS AND MATERIALS: We conducted a single-institution institutional review board-approved retrospective review of 15 female left-sided breast cancer patients treated between July 2012 and June 2013 with conventional whole breast radiation. We compared daily port films with treatment planning digitally reconstructed radiographs to establish daily setup accuracy, then used Calypso tracings to compare the position of the CW during the daily port film with the position of the CW during that day's treatment to determine the reproducibility of the breath hold position. Finally, we created competing treatment plans not using DIBH and used a paired t test to compare mean heart (MH) and left anterior descending (LAD) coronary artery dose between the 2 techniques. RESULTS: Mean total error (inter- and intrafraction) was dominated by interfraction error and was greatest in the longitudinal direction with a mean of 2.13 mm and 2 standard deviations of 8.2 mm. DIBH significantly reduced MH and LAD dose versus free breathing plans (MH, 1.26 Gy vs 2.84 Gy, P ≤ .001; LAD, 5.49 Gy vs 18.15 Gy, P ≤ .001). CONCLUSIONS: This study demonstrates that DIBH with electromagnetic confirmation of CW position is feasible, and allows potential improvement in the accurate delivery of adjuvant RT therapy for breast cancer. Published by Elsevier Inc.
PURPOSE: With most patients now living long after their breast cancer diagnosis, minimizing long-term side effects of breast cancer treatment, such as reducing late cardiac and pulmonary side effects of radiation therapy (RT), is particularly important. It is now possible to use an electromagnetic tracking system to allow real-time tracking of chest wall (CW) position during the delivery of RT. Here, we report our experience using electromagnetic surface transponders as an added measure of CW position during deep inspiration breath hold (DIBH). METHODS AND MATERIALS: We conducted a single-institution institutional review board-approved retrospective review of 15 female left-sided breast cancerpatients treated between July 2012 and June 2013 with conventional whole breast radiation. We compared daily port films with treatment planning digitally reconstructed radiographs to establish daily setup accuracy, then used Calypso tracings to compare the position of the CW during the daily port film with the position of the CW during that day's treatment to determine the reproducibility of the breath hold position. Finally, we created competing treatment plans not using DIBH and used a paired t test to compare mean heart (MH) and left anterior descending (LAD) coronary artery dose between the 2 techniques. RESULTS: Mean total error (inter- and intrafraction) was dominated by interfraction error and was greatest in the longitudinal direction with a mean of 2.13 mm and 2 standard deviations of 8.2 mm. DIBH significantly reduced MH and LAD dose versus free breathing plans (MH, 1.26 Gy vs 2.84 Gy, P ≤ .001; LAD, 5.49 Gy vs 18.15 Gy, P ≤ .001). CONCLUSIONS: This study demonstrates that DIBH with electromagnetic confirmation of CW position is feasible, and allows potential improvement in the accurate delivery of adjuvant RT therapy for breast cancer. Published by Elsevier Inc.