Yukinori Matsuo1, Nami Ueki2, Kenji Takayama3, Mitsuhiro Nakamura2, Yuki Miyabe2, Yoshitomo Ishihara2, Nobutaka Mukumoto2, Shinsuke Yano4, Hiroaki Tanabe3, Shuji Kaneko5, Takashi Mizowaki2, Hajime Monzen2, Akira Sawada6, Masaki Kokubo7, Masahiro Hiraoka2. 1. Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: ymatsuo@kuhp.kyoto-u.ac.jp. 2. Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 3. Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe, Japan. 4. Clinical Radiology Service Division, Kyoto University Hospital, Kyoto, Japan. 5. Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Mitsubishi Heavy Industries, Ltd., Tokyo, Japan. 6. Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Japan. 7. Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Japan.
Abstract
PURPOSE: To evaluate feasibility and acute toxicities after dynamic tumour tracking (DTT) irradiation with real-time monitoring for lung tumours using a gimbal mounted linac. MATERIALS AND METHODS: Spherical gold markers were placed around the tumour using a bronchoscope prior to treatment planning. Prescription dose at the isocentre was 56 Gy in 4 fractions for T2a lung cancer and metastatic tumour, and 48 Gy in 4 fractions for the others. Dose-volume metrics were compared between DTT and conventional static irradiation using in-house developed software. RESULTS: Of twenty-two patients enrolled, DTT radiotherapy was successfully performed for 16 patients, except 4 patients who coughed out the gold markers, one who showed spontaneous tumour regression, and one where the abdominal wall motion did not correlate with the tumour motion. Dose covering 95% volume of GTV was not different between the two techniques, while normal lung volume receiving 20 Gy or more was reduced by 20%. A mean treatment time per fraction was 36 min using DTT. With a median follow-up period of 13.2 months, no severe toxicity grade 3 or worse was observed. CONCLUSIONS: DTT radiotherapy using a gimbal mounted linac was clinically feasible for lung treatment without any severe acute toxicity.
PURPOSE: To evaluate feasibility and acute toxicities after dynamic tumour tracking (DTT) irradiation with real-time monitoring for lung tumours using a gimbal mounted linac. MATERIALS AND METHODS: Spherical gold markers were placed around the tumour using a bronchoscope prior to treatment planning. Prescription dose at the isocentre was 56 Gy in 4 fractions for T2a lung cancer and metastatic tumour, and 48 Gy in 4 fractions for the others. Dose-volume metrics were compared between DTT and conventional static irradiation using in-house developed software. RESULTS: Of twenty-two patients enrolled, DTT radiotherapy was successfully performed for 16 patients, except 4 patients who coughed out the gold markers, one who showed spontaneous tumour regression, and one where the abdominal wall motion did not correlate with the tumour motion. Dose covering 95% volume of GTV was not different between the two techniques, while normal lung volume receiving 20 Gy or more was reduced by 20%. A mean treatment time per fraction was 36 min using DTT. With a median follow-up period of 13.2 months, no severe toxicity grade 3 or worse was observed. CONCLUSIONS:DTT radiotherapy using a gimbal mounted linac was clinically feasible for lung treatment without any severe acute toxicity.