Measurement and Evaluation of the Impact of a Carbon Fiber Couch in Radiation Oncology

Hashem, Mostafa; Alassdei, Aml S; El-Fadl, A. Abu; Abu Sehly, A; Metwally, Hossam

doi:10.21608/aunj.2023.223469.1057

Measurement and Evaluation of the Impact of a Carbon Fiber Couch in Radiation Oncology

Document Type : Novel Research Articles

Authors

¹ Department of Radiation Oncology and Nuclear Medicine, South Egypt Cancer Institute, Assiut University, Assiut, Egypt-1Department of Radiation Oncology and Nuclear Medicine, South Egypt Cancer Institute, Assiut University, Assiut, Egypt

² Department of Physics, Faculty of Science, Assiut University, Assiut, Egypt-Department of Physics, Faculty of Science, Aden University, Yemen.

³ Department of Physics, Faculty of Science, Assiut University, Assiut, Egypt-Lap. of Smart Materials for Energy Futures, Faculty of Science, Assiut University, Assiut, Egypt

⁴ Department of Physics, Faculty of Science, Assiut University, Assiut, Egypt

⁵ Department of Radiology, Faculty of Medicine, Assiut University, Assiut, Egypt

10.21608/aunj.2023.223469.1057

Abstract

Carbon fiber couch inserts reduce set-up errors caused by sagging in radiotherapy treatment couches. Studies have described such inserts as radio translucent with negligible radiation field attenuation. There appears to be no evidence in the literature that the thickest region affects attenuation and dose distribution during external beam radiotherapy. The majority of these tests were carried out with the radiation field normally incident on the center of the couch. This study evaluated and improved the calculated dose attenuation for the under-couch fields.
At normal incidence, the couch attenuated 6 MV photons by 10.5%,9.3%, 8.9%, and 8.6% for 5 × 5 cm2, 10 × 10 cm2, 15×15 cm2and 20×20 cm2 field sizes, respectively. We further found attenuation to be gantry angle dependent, with the highest attenuation recorded at 180° – at which angle the couch attenuated the 6 MV photon beam by 10.5% for the 5 × 5 cm2 and 9.3% for the 10 × 10 cm2 field sizes. Similarly, a 10 MV photon beam was attenuated by 8.6% and 7.7% for the 5 × 5 cm2 and 10 × 10 cm2, respectively, and 7.3% for both 15×15 cm2 and 20×20 cm2 field sizes, furthermore, a 15 MV was attenuated by 7.4%, 6.6%, 6.5% and 6.4% for 5 × 5 cm2, 10 × 10 cm2, 15×15cm2, and 20×20 cm2 field sizes, respectively. while the attenuation at 1600 and 1400 was less where the lowest attenuation recorded at 1400 at which angle the couch attenuated the 15 MV photon beam by 1.5.

Keywords