A Comparative study of radiation doses and treatment area dependence in thermoluminescence dosimetry systems and metal oxide semiconductor field effect transistors

Abstract

J o u rn a l O f T u rg u t O za l M e d ic a l C e n te r w w w .jto m c .o rgA C om parative Study o f Radiation Doses and Treatm ent Area Dependence in Thermolum inescence Dosim etry Systems and Metal O xide Sem iconductor Field Effect Transistors Eda Kaya Pepele1, Songül Barlaz Us2, Kadir Yaray3, Celalettin Eroğlu3, Bahar Dirican4, Serdar Soyuer3 1İnönü U niversity, Faculty o f M e d icin e , D e p a rtm e n t o f R adiation O n co lo g y, M alatya, T urkey 2M ersin U niversity, Faculty o f M e d icin e , D e p a rtm e n t o f R adiation O n co lo g y, M ersin, Turkey 3Erciyes U niversity, Faculty o f M e d icin e , D e p a rtm e n t o f R adiation O n co lo g y, Kayseri, Turkey 4G ülhane M ilita ry M e d icin e A cadem y, D e p a rtm e n t o f R adiation O n c o lo g y , A nkara, T urkey AbstractAim: This study aims at examining the differences between thermoluminescense dosimeters and metal oxide semiconductor field effect transistors in terms of radiation doses at different photon energies treatment area dependence in patients who recieved radiotherapy at the Department of Radiation Oncology, İnönü University. Material and Methods: Thermoluminescense dosimeter systems and metal oxide semiconductor field effect transistors were used at 6MV and 25MV in the range of 25-1000 cGy radiation doses to examine radiation dose dependence. Results were evaluated by taking measurements of treatment areas 5x5, 10x10, 15x15, 20x20, 25x25, 30x30, and 40x40 cm2, respectively, to specify treatment area dependence of these systems. Results: In both thermoluminescense dosimeters (TLD) and metal oxide semiconductor field effect transistors (MOSFET), reading values at 6 MV and 25 MV photon energies remained up to 800 cGy. We observed that both systems deviate from linearity at doses above 800 cGy. In TLDs, we recorded a %±1 (6 MV photon energy) and %+4 (25 MV photon energy) change in reading values. This change was %±1 (6 MV photon energy) and %+4 (25 MV photon energy) in MOSFETs. Conclusion: Both dosimeter systems have advantages and disadvantages in terms of accuracy and applicability. Being familiar with dosimeter systems is very important in identifying the accuracy of dose to be admisnistered.