Applicator with dosimeter for in vivo dose evaluation

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K15347
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Medical Physics and Radiological Technology
• Research Institution: Osaka University
• Principal Investigator: Koizumi Masahiko 大阪大学, 医学系研究科, 教授 (90186594)
• Co-Investigator(Kenkyū-buntansha): 隅田 伊織 大阪大学, 医学系研究科, 助教 (10425431) ; 高橋 豊 大阪大学, 医学(系)研究科(研究院), その他 (40353461)
• Research Collaborator: Kaneko Akari 大阪大学, 医学系研究科
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 医学物理学 / 小線源治療 / 線量分布 / 放射線治療 / 小線源アプリケータ / 高線量率組織内照射 / 放射線治療品質管理 / 線量評価

Outline of Final Research Achievements

We developed a novel real-time in vivo dosimeter which is incorporated into the brachytherapy applicator (A tandem and avoids) for uterine cervix cancer. We identified that 0.5 mm diameter of semi-sphere plastic scintillator with a 1.0 mm optical fiber was optimal to detect photons from Ir-192 sources while minimizing detector size. Specifically, dependences of energy, azimuthal and radial angular responses were within 3.5%, 3%, and 1%, respectively. The measurement reproducibility was within 2.2%.
We modified fletcher-Suite applicators to incorporate the detectors in which the original ovoids were replaced with our newly developed ovoids. This ovoids allows for incorporating 4 detectors with radio opaque markers to identify the detector position in CT images without significant increase of the size. The tandem applicator also incorporates to two dosimeters attached with a heat compression tube again without significant increase of the size.

Free Research Field

放射線腫瘍学