Output factor determination based on Monte Carlo simulation for small cone field in 10-MV photon beam

被引：4
作者：
Fukata K. [1 ]
Sugimoto S. [2 ]
Kurokawa C. [2 ]
Saito A. [3 ]
Inoue T. [4 ]
Sasai K. [2 ]
机构：
[1] Cancer Center, Keio University School of Medicine, 35 Shinano-machi, Shinjuku, Tokyo
[2] Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo
[3] Department of Radiation Oncology, Hiroshima University Hospital, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8551, Hiroshima
[4] Department of Radiology, Juntendo University Urayasu Hospital, Tomioka 2-1-1, Urayasu-shi, Chiba
来源：
Radiological Physics and Technology | 2018年 / 11卷 / 2期
关键词：
Dosimetry; Monte Carlo; Small field; SRS;
D O I：
10.1007/s12194-018-0455-4
中图分类号：
学科分类号：
摘要：
The difficulty of measuring output factor (OPF) in a small field has been frequently discussed in recent publications. This study is aimed to determine the OPF in a small field using 10-MV photon beam and stereotactic conical collimator (cone). The OPF was measured by two diode detectors (SFD, EDGE detector) and one micro-ion chamber (PinPoint 3D chamber) in a water phantom. A Monte Carlo simulation using simplified detector model was performed to obtain the correction factor for the detector measurements. About 12% OPF difference was observed in the measurement at the smallest field (7.5 mm diameter) for EDGE detector and PinPoint 3D chamber. By applying the Monte Carlo-based correction factor to the measurement, the maximum discrepancy among the three detectors was reduced to within 3%. The results indicate that determination of OPF in a small field should be carefully performed. Especially, detector choice and appropriate correction factor application are very important in this regard. © 2018, Japanese Society of Radiological Technology and Japan Society of Medical Physics.
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页码：192 / 201
页数：9
相关论文
共 39 条
[1]  
Schell M.C., Bova F.J., Larson D.A., Leavitt D.D., Lutz W.R., Podgorsak E.B., Wu A., Stereotactic Radiosurgery Report of Task Group 42 Radiation Therapy Committee, Oncol, 54, (1995)
[2]  
Das I.J., Downes M.B., Kassaee A., Tochner Z., Choice of radiation detector in dosimetry of stereotactic radiosurgery-radiotherapy, J Radiosurgery, 3, pp. 177-186, (2000)
[3]  
Benedict S.H., Yenice K.M., Followill D., Galvin J.M., Hinson W., Kavanagh B., Keall P., Lovelock M., Meeks S., Papiez L., Purdie T., Sadagopan R., Schell M.C., Salter B., Schlesinger D.J., Shiu A.S., Solberg T., Song D.Y., Stieber V., Timmerman R., Tome W.A., Verellen D., Wang L., Yin F.-F., Tome W.A., Verellen D., Wang L., Yin F.-F., Stereotactic body radiation therapy: the report of AAPM Task Group 101, Med Phys, 37, pp. 4078-4101, (2010)
[4]  
Li X.A., Soubra M., Szanto J., Gerig L.H., Lateral electron equilibrium and electron contamination in measurements of head-scatter factors using miniphantoms and brass caps, Med Phys, 22, pp. 1167-1170, (1995)
[5]  
Francescon P., Cora S., Cavedon C., Scalchi P., Reccanello S., Colombo F., Use of a new type of radiochromic film, a new parallel-plate micro-chamber, MOSFETs, and TLD 800 microcubes in the dosimetry of small beams, Med Phys, 25, pp. 503-511, (1998)
[6]  
Sauer O.A., Wilbert J., Measurement of output factors for small photon beams, Med Phys, 34, (2007)
[7]  
Scott A.J.D., Nahum A.E., Fenwick J.D., Using a Monte Carlo model to predict dosimetric properties of small radiotherapy photon fields, Med Phys, 35, pp. 4671-4684, (2008)
[8]  
Das I.J., Cheng C.-W., Watts R.J., Ahnesjo A., Gibbons J., Li X.A., Lowenstein J., Mitra R.K., Simon W.E., Zhu T.C., Accelerator beam data commissioning equipment and procedures: report of the TG-106 of the Therapy Physics Committee of the AAPM, Med Phys, 35, (2008)
[9]  
Francescon P., Cora S., Cavedon C., Total scatter factors of small beams: a multidetector and Monte Carlo study, Med Phys, 35, (2008)
[10]  
Underwood T.S.A., Winter H.C., Hill M.A., Fenwick J.D., Detector density and small field dosimetry: integral versus point dose measurement schemes, Med Phys, 40, (2013)
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