Evaluation of characteristics of high-energy electron beams using N-isopropyl-acrylamide gel dosimeter. (November 2017)

• Record Type: Journal Article
• Authors: Shih, Tian-Yu; Yen, Tsung-Hsien; Liu, Yan-Lin; Luzhbin, Dmytro; Wu, Jay
• Is Part Of: Radiation physics and chemistry. Volume 140(2017)
• Page Start: 379
• Page End: 382
• Publication Date: 2017-11
• Subjects: Electron beam -- N-NIPAM gel -- Percentage depth dose; Radiation chemistry -- Periodicals; Radiometry -- Periodicals; Radiation -- Periodicals; Chimie sous rayonnement -- Périodiques; 539.2
• DOI: 10.1016/j.radphyschem.2017.02.022
• Languages: English
• ISSNs: 0969-806X

Abstract

Abstract: The advantage of electron beam radiotherapy is that the absorbed dose rapidly decreases with the increasing depth, which can prevent damage to deeper organs and tissues. Accurately evaluating the absorbed dose in the superficial tumor is imperative. This study assessed the characteristics of electron beams by using the N-isopropyl-acrylamide (n-NIPAM) gel dosimeter. The n-NIPAM gel was composed of 6% gelatin, 5% monomer, and 2.5% cross-linker with 5 mM tetrakis (hydroxymethyl) phosphonium chloride for deoxygenation. The gel was irradiated with 6-, 9-, and 12-MeV electron beams with dose rates of 100−600 MU/min, respectively. The energy dependence and dose rate dependence were assessed. The beam profiles and percentage depth doses were measured and compared with the results of the Gafchromic film and ionization chamber. The linearity of the n-NIPAM gel under 6-, 9-, and 12-MeV electrons was larger than 0.990 with 2% variation in sensitivity. The sensitivity of the gel under 100−600 MU/min showed 5% variations. The energy and dose rate dependence can be negligible. The beam profiles and percentage depth doses measured by the n-NIPAM gel matched well with the results of the ionization chamber and film. This study reveals the possibility of using the n-NIPAM gel dosimeter for electron beam measurements in clinical radiotherapy. Highlights: The characteristics of electron beams were assessed by the n-NIPAM gel dosimeter. No significant energy dependence existed. No significant output rate dependence existed. The flatness and symmetry of the beam profile were around 3%. The percentage depth dose was measured by the n-NIPAM gel.