Development and characterization of optical readout well-type glass gas electron multiplier for dose imaging in clinical carbon beams. (February 2021)

• Record Type: Journal Article
• Authors: Fujiwara, Takeshi; Koba, Yusuke; Mitsuya, Yuki; Nakamura, Riichiro; Tatsumoto, Ryuta; Kawahara, Shuto; Maehata, Keisuke; Yamaguchi, Hidetoshi; Chang, Weishan; Matsufuji, Naruhiro; Takahashi, Hiroyuki
• Is Part Of: Physica medica. Volume 82(2021)
• Page Start: 72
• Page End: 78
• Publication Date: 2021-02
• Subjects: Hadron therapy -- QA -- Carbon beam -- Dose imaging -- GEM -- Glass GEM; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2021.01.068
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: Submillimeter resolution 2-D dose imaging detector for hadron therapy. Removing Cherenkov light contamination improved dosimetry response. Well-type Glass GEM structure significantly improved LET dependance. A Bragg peak of a carbon beam peak-to-plateau ratio of more than 4 was measured. Abstract: The use of carbon ion beams in cancer therapy (also known as hadron therapy) is steadily growing worldwide; therefore, the demand for more efficient dosimetry systems is also increasing because daily quality assurance (QA) measurements of hadron radiotherapy is one of the most complex and time consuming tasks. The aim of this study is to develop a two-dimensional dosimetry system that offers high spatial resolution, a large field of view, quick data response, and a linear dose–response relationship. We demonstrate the dose imaging performance of a novel digital dose imager using carbon ion beams for hadron therapy. The dose imager is based on a newly-developed gaseous detector, a well-type glass gas electron multiplier. The imager is successfully operated in a hadron therapy facility with clinical intensity beams for radiotherapy. It features a high spatial resolution of less than 1 mm and an almost linear dose–response relationship with no saturation and very low linear-energy-transfer dependence. Experimental results show that the dose imager has the potential to improve dosimetry accuracy for daily QA.