Investigation of Dosimetric Characteristics of a MOSFET Detector for Clinical Electron Beams
AbstractObjective: Studying of the fundamental dosimetric characteristics of metal oxide semiconductor field effect transistor (MOSFET) detectors to evaluate its use in clinical electron beam irradiations. Materials and Methods: In this study, GE-MS Saturne-43 linear accelerator was used . At first, Mosfet dedectors were calibrated for all electron energies. The fundamental dosimetric characteristics such as dose-linearity, reproducibility, angular dependence and field size dependence of MOSFET detectors were studied for 4,6,9,12,16 and 18 MeV electron energies. Results: Good linearity of the MOSFET dedector in the dose range of 10-500 cGy showed that it could be reliable detector for all electron applications. The energy dependence of a MOSFET dedector was within 3.0% for 6–18 MeV electron beams and 8% for 4 MeV ones. The results of the measurements performed using a spherical wax mini fantom demonstrate that the angular dependence of the MOSFET detector is small. MOSFET reproducibility is within 2%. Conclusion: This study shows that MOSFET detectors are suitable for dosimetry of electron beams in the energy range of 4–18 MeV. From the results observed it can be concluded that by applying proper calibration and correction factors, MOSFET may be used as in vivo detector for the dose verification for patients undergoing electron beam radiotherapy.
Protection of the patient in radiation therapy. ICRP publication 44. International Commission on Radiological Protection (ICRP).Ann ICRP 1985 ;15:2
Belleti S, Dutreix G, Garavaglia G, Gfirtner H, Haywood J, Jessen KA, et al. Quality assurance in radiotherapy: the importance of medical physics staffing levels.Recommendations from an ESTRO/EFOMP joint task group. Radiother Oncol 1996; 41: 89-94.
Huykens D, Bogarets R, Verstraete J, Loof M, Nystrom H, Fiorino C,et al. Practical guidelines fort he implementation of in vivo dosimetry with diodes in external beam radiotherapy with photon beams (entrance dose). Booklet no:5 ESTRO; 2001.
Thomson and Nielsen Electronics Ltd (Ottowa). Technical note no:4 1996.
Marcie S, Charpiot E, Bensadour RJ,Ciasis G,Herault J,Costa A, et al. In vivo measurements with MOSFET dedectors in oropharnynx and nasopharynx intensity modulated radiotherapy. Int J Radiat Oncol Biol Phys 2005;61:1603-6.
Dong SL, Chu TC,Lan GY,Wu TH,Lin YC,Lee JS.Characterization of high sensitivity metal oxide semiconductor field effect transistor dosimeters system and LiF: Mg,Cu,P thermluminescence dosimeters for use diagnostic radiology.Appl Radiat Isot 2002;57:883-91.
Manigandan D,Bharanidharan G,Aruna P,Devan K, Elangovan D, Patil V, Tamilarasan R, Vasanthan S,Ganesan S.Dosimetric characteristics of a MOSFET dosimeter for clinical electron beams. Physica Medica 2009; 25: 1417.
Bloemen-Van Gurp EJ,Minken AWH,Mijnheer BJ,Dehing-Oberye Cary JG,Lambin Philips.Clinical implementation of MOSFET dedectors for dosimetry in electron beams. Radiother Oncol 2006;80:288-95.
All opinions and reports within the articles that are published in the Gazi Medical Journal are the personal opinions of author(s). Gazi University, Editors and the publisher do not accept any responsibility for these articles. The journal is printed on acid-free paper.