Purpose: A new motion-based gated proton therapy for the treatment of orbital tumors using
real-time eye-tracking system was designed and evaluated.
Methods:We developed our system by image-pattern matching, using a normalized cross-correlation
technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To
measure the pixel spacing of an image consistently, four different calibration modes such as the
point-detection, the edge-detection, the line-measurement, and the manual measurement mode were
suggested and used. After these methods were applied to proton therapy, gating was performed, and
radiation dose distributions were evaluated.
Results: Moving phantom verification measurements resulted in errors of less than 0.1 mm for given
ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment
delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra
for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure.
The analysis from clinical results suggests that the average of eye movements depends distinctively
on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively.
Conclusions: The developed automatic eye-tracking based beam-gating system enabled us to perform
high-precision proton radiotherapy of orbital tumors. ? 2012 American Association of Physicists in
Medicine.

 

 

 

Dongho Shin
Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
Seung Hoon Yoo
Department of Radiation Oncology, CHA Bundang Medical Center, CHA University,
Seongnam, Gyeonggi 463-712, Republic of Korea
Sung Ho Moon
Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
Myonggeun Yoon
Department of Radiological Science, Korea University, Seoul 136-703, Republic of Korea
Se Byeong Lee
Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
Sung Yong Parka)
Proton Therapy Center, McLaren Cancer Institute, Flint, Michigan 48532

 

Medical Physics, Vol. 39, No. 7, July 2012

 The aim of this study was to examine the current status of proton therapy in Korea and to review the dosimetric benefits of proton beam therapy (PBT) over intensitymodulated radiotherapy (IMRT) for lung cancer treatment. Data from patients treated betweenMarch 2007 and February 2011 in Korea using proton therapy were analyzed retrospectively. For comparison, IMRT and PBT in the scattering mode were planned for lung cancer patients. Dosimetric benefits and organ-specific radiation-induced cancer risks were based on comparisons of dose volume histograms (DVH) and secondary radiation doses, respectively. On average, the doses delivered by PBT to the lung, esophagus and spinal cord were 17.4%, 2.5% and 43.6% of the prescription dose, respectively, which were lower than the doses delivered by IMRT (31.5%, 11.8% and 45.3%, respectively). Although the average doses delivered by PBT to the lung and spinal cord were significantly lower than those by IMRT, these differences were reduced in the esophagus.While the average secondary dose from PBT (measured at 20?50 cm from the isocenter) was 1.33?0.86 mSv/Gy, the average secondary dose from IMRT was 3.3?1.0 mSv/Gy. Compared with IMRT techniques, PBT showed improvements in most dosimetric parameters for lung cancer patients,with lower secondary radiation doses.

 

 

 

 

Myonggeun Yoon
Department of Radiological Science, College of Health Science, Yonsei University, Wounju, Korea

 

Thoracic Cancer ISSN 1759-7706

 

 In this work, three-dimensional (3D) film-based proton beam measurements were used for the first time to verify the patientspecific radiation dose distribution, beam range and compensator shape. Three passively scattered proton beams and one uniform scanning proton beam were directed onto an acrylic phantom with inserted Gafchromic EBT films. The average gamma index for a comparison of the dose distributions was less than one for 97.2 % of all pixels from the passively scattered proton beams and 98.1 % of all pixels for the uniform scanning proton beams, with a 3 % dose and a 3 mm distance-to-dose agreement tolerance limit. The results also showed that the average percentage of points within the acceptance criteria for proton beam ranges was 94.6 % for the passively scattered proton beams. Both the dose distribution and the proton beam range determined by the 3D EBT film measurement agreed well with the planning system values.

 

 

 

Jinsung Kim1, Myonggeun Yoon2,*, Seonkyu Kim3, Dongho Shin3, Se Byeong Lee3, Young Kyung Lim3,
Dong Wook Kim4 and Sung Yong Park5
1Department of Radiation Oncology, Samsung Medical Center, Seoul, Korea
2Department of Radiological Science, College of Health Science, Korea University, Seoul, Korea
3Proton Therapy Center, National Cancer Center, 809 Madu 1-dong, Ilsandong-gu, Goyang, Korea
4Department of Radiation Oncology, Kyung Hee University Hospital at Kangdong, Seoul, Korea
5McLaren Regional Medical Center, Great Lakes Cancer Institute, Flint, MI, USA

Radiation Protection Dosimetry (2012), Vol. 151, No. 2, pp. 272?277