Program Information

Cardiac Movement in Deep Inspiration Breath-Hold for Left-Breast Cancer Radiotherapy

M Kim

M Kim*, S Lee , T Suh , Department of Biomedical Engineering, Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul

Presentations

SU-E-J-33 Sunday 3:00PM - 6:00PM Room: Exhibit Hall

Purpose: The present study was designed to investigate the displacement of heart using Deep Inspiration Breath Hold (DIBH) CT data compared to free⁻breathing (FB) CT data and radiation exposure to heart.

Methods: Treatment planning was performed on the computed tomography (CT) datasets of 20 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ≥ 95% of the prescribed dose and that the volume inside the CTV receiving > 107% of the prescribed dose should be minimized. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated.

Results: The maximum and minimum left⁻right (LR) displacements of heart were 8.9 mm and 3 mm, respectively. The heart moved > 4 mm in the LR direction in 17 of the 20 patients. The distances between the heart and left breast ranged from 8.02⁻17.68 mm (mean, 12.23 mm) and 7.85⁻12.98 mm (mean, 8.97 mm) with DIBH CT and FB CT, respectively. The maximum doses to the heart were 3115 cGy and 4652 cGy for the DIBH and FB CT dataset, respectively.

Conclusion: The present study has demonstrated that the DIBH technique could help to reduce the risk of radiation dose⁻induced cardiac toxicity by using movement of cardiac; away from radiation field. The DIBH technique could be used in an actual treatment room for a few minutes and could effectively reduce the cardiac dose when used with a sub⁻device or image acquisition standard to maintain consistent respiratory motion.


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