홀뮴-166을 이용한 방사선 치료의 방사선흡수선량 = Absorbed dose for radiation therapy using Ho-166

다국어 초록 (Multilingual Abstract)

Ho-166 was produced by neutron reaction in a reactor at the Korea Atomic Energy Institute (Taejon, Korea). Ho-166 emits a high energy beta particles with a maximum energy of 1.85 MeV and small proportion of gamma rays (80 keV). Therefore, the radiation absorbed dose estimation could be based on the in-vivo quantification of the activity in tumors from the gamma camera images. Transmission factor over an area of interest was calculated from the ratio of counts in selected regions. Thirty millicuries(1110MBq) of Ho-166-CHICO was injected into the right hepatic arterial branch supplying hepatoma. Regions of interest (ROIs) were drawn over the organs in both the anterior and posterior views. The activity in those ROIs was estimated from geometric mean, calibration factor and transmission factors. Absorbed dose was calculated using the Marinelli formula and Medical Internal Radiation Dose (MIRD) schema. Tumor dose of the patient treated with 1110 MBq(30 mCi) Ho-166 was calculated to be 179.7 Gy. Dose distribution to normal liver, spleen, lung and bone was 9.1, 10.3, 3.9, 5.0 % of the tumor dose respectively. Tmor dose and absorbed dose to surrounding structures were calculated by daily external imaging after the Ho-166 therapy for hepatoma. The purpose of our another study was to estimate the absorbed dose distribution of Ho-166 endovascular beta irradiation using angio catheter.
We used GafChromic film for the estimation of the absorbed dose by beta particles. The exposed films were read using a videodensitometer. With a modified micrometer, the film was positioned accurately to the surface of the balloon in water. The balloon was filled with Ho-166 solution to a pressure of 4 atm. Several film exposures were made with varying irradiation times and activities. The radiation absorbed dose rates were 1.02, 0.51 and 0.35 Gy/min/GBq/ml at balloon surface, 0.5 and 1 mm from the balloon surface respectively. The absorbed dose distribution revealed that Ho-166 was a good source for endovascular irradiation since the beta range from Ho-166 was very short avoiding unnecessary irradiation to the normal tissue. A clinically applicable irradiation and duration of exposure were achievable utilizing our system.

목차 (Table of Contents)

• 목차
• I. 서론 = 1
• II. 이론 = 4
• 1. 방사선 물리의 용어 및 단위 = 4
• 2. 의료용 방사성 동위원소의 생산 = 19
• 3. 방사선과 물질과의 상호작용 = 24
• 4. 치료용 방사성 의약품 = 43
• 5. 방사성 의약품 치료 = 46
• 6. 방사선 흡수선량 = 52
• III. 실험기구 및 방법 = 64
• 1. Ho-166 과 Ho-166-CHICO = 64
• 2. 간암에 주입한 Ho-166-CHICO 의 평면영상을 이용한 흡수선량의 계산 = 78
• 3. Ho-166 을 이용한 관상동맥 재협착 방지를 위한 흡수선량의 측정 = 85
• IV. 실험결과 및 고찰 = 88
• V. 결론 = 103
• 참고문헌 = 105