Author(s)

Keiichi Nakagawa^1*, Kanabu Nawa¹, Masatoshi Hashimoto², Shuri Aoki¹, Yoshihiro Kaneko¹, Hideomi Yamashita¹, Akihiro Haga¹

¹Department of Radiology, University of Tokyo Hospital, Tokyo, Japan.
²Department of Radiation Oncology, The Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan.

A technique for multiple deep-inspiration breath-hold (DIBH) volumetric modulated arc therapy (VMAT) for a lung tumor has been proposed with 10 MV flattening-filter-free beams and an image sensor measuring a distance map to thorax surface. Planning CT images were acquired under a DIBH condition and a clinical target volume (CTV) was contoured. This procedure was repeated five times and an internal target volume (ITV) among the multiple DIBHs was created by integrating the five CTVs. A planning target volume (PTV) was defined by adding an isotropic margin of 5 mm to the ITV. Immediately before treatment, a 30-second half-arc cone-beam computer tomography (CBCT) imaging was performed under another DIBH condition, and the couch was repositioned so that tumor may be located inside the PTV contours. An infrared distance measurement device having laser diodes and an image sensor was attached to the couch, and a distance map to the patient thorax surface was recorded as a reference during still another DIBH condition. A half-arc segmented VMAT beams with two beam interrupts were delivered to the patient under multiple DIBHs, where the delivery time of each of the three segmented beams was 30 seconds. During the beam delivery, the distance map was monitored in real time to confirm that the distance to the thorax surface remained unchanged. In-treatment CBCT images suggested that the tumor position at the time of tumor registration was accurately reproduced during the DIBH VMAT delivery.

Deep Inspiration Breath-Hold, DIBH, FFF, VMAT, Kinect, Lung

Nakagawa, K. , Nawa, K. , Hashimoto, M. , Aoki, S. , Kaneko, Y. , Yamashita, H. and Haga, A. (2017) A Half-Arc Multiple Deep-Inspiration Breath-Hold Volumetric Modulated Arc Therapy for a Lung Tumor with 10 MV Flattening-Filter-Free Beams and an Image Sensor Measuring a Distance Map to Thorax Surface: An Initial Clinical Experience. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 6, 31-35. doi: 10.4236/ijmpcero.2017.61004.