Radiotherapy dose verification on a customised head and neck perspex phantom

10th International Seminar on Medical Physics; 1st AMDI International Oncology Symposium

物理学;医药卫生

Eng, K.Y.^1 ; Kandaiya, S.^1 ; Yahaya, N.Z.^2

School of Physics, Universiti Sains Malaysia, Penang, Malaysia^1

School of Distance Education, Universiti Sains Malaysia, Penang, Malaysia^2

关键词: Dose measurement;    Dose verification;    Gamma analysis;    Intensity-modulated radiotherapy;    Measuring tools;    Organs at risks;    Target volumes;    Treatment planning systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/851/1/012020/pdf
DOI  :  10.1088/1742-6596/851/1/012020

学科分类：卫生学

来源: IOP

【 摘 要 】

IMRT dose planned for head and neck radiotherapy was verified using a customised acrylic head-and-neck phantom. The dosimeters used were calibrated Gafchromic EBT2 film and metal-oxide-semiconductor-field-effect-transistor (MOSFET). Target volumes (TV) and organs-at-risk (OAR) which were previously contoured by an oncologist on selected nasopharynx (NPC) patients were transferred to this phantom by an image fusion procedure. Three radiotherapy plans were done: Plan1 with 7-fields intensity-modulated radiotherapy (IMRT) of prescribed dose 70 Gy using 33 fractions; Plan2 with 7-fields IMRT plan at 70 Gy and 35 fractions; and Plan3 which was a mid-plane-dose (MPD) plan of 66 Gy at 33 fractions. The dose maps were first verified using MapCheck2 by SNC-PatientTM software. The passing rates from gamma analysis were 97.7% (Plan1), 93.1% (Plan2) and 100% (Plan3). Percentage difference between Treatment Planning System (TPS) calculated dose and MOSFET measured dose was comparatively higher than those from EBT2. Calculated dose and EBT2 measured doses showed differences of within the range of ±3% for TV and