MEASUREMENT OF ABSORPTION DOSE OUTSIDE IRRADIATION FIELD IN IMRT.
The absorption dose outside the irradiation field for prostate intensity-modulated radiation therapy was measured and evaluated by comparison with calculated values of radiation treatment planning system (TPS). The values of TPS calculated were using Varian CLINAC21EX/Eclipse and TomoTherapy Planning System for constant irradiation time. The absorption dose was measured by placing a glass-element dosemeter in a human-bone enclosure phantom with a planning target volume inside the irradiation field. The organs at risk were the rectum, spinal cord, thyroid, eyeball and the left lung. The calculated values of TPS, Varian CLINAC21EX/Eclipse and TomoTherapy Planning System were calculated, up to 17 and 55 cm from the isocenter, respectively. The absorbed dose outside the irradiation field diverged with increased distance from the isocenter (Varian/Eclipse: p = 0.03, TomoTherapy Planning System: p = 0.25). The calculated values for the absorbed dose outside the irradiation field were underestimated.
Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan.|Department of Radiology, Otsu Red Cross Hospital, Otsu, Shiga, Japan.
Makoto
M
Hirata
Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan.
Hajime
H
Monzen
Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan.
Kohei
K
Hanaoka
Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan.
Yasumasa
Y
Nishimura
D006801:Humans; D008297:Male; D008953:Models, Anatomic; D058958:Organs at Risk; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated