• 대한방사선치료학회지
• /
• 제1권1호
• /
• pp.63-69
• /
• 1985

High energy electron beams took effect for tumor radio-therapy, however, had a lot of problems in clinical application because of various conversion factors and complication of physical reactions. Therefore, we had experimentally studied the important properties of high energy electron beams from the linear accelerator, LMR-13, installed in Yonsei Cancer Center. The results of experimental studies on the problems in the 8, 10, 12 Mev electron beam therapy were reported as following. 1. On the measurements of the outputs and absorbed does, the ionization type dosimeters that had calibrated by $^{90}Sr$ standard source were suitable as under $3\%$ errors for high energy electrons to measure, but measuring doses in small field sizes and the regions of rapid fall off dose with ionization chambers were difficult. 2. The electron energy were measured precisely with energy spectrometer consisted of magnet analyzer and tele-control detector and the practical electron energy was calculated under $5\%$ errors by maximum range of high energy electron beam in the water. 3. The correcting factors of perturbated dose distributions owing to radiation field, energy and material of the treatment cone were checked and described systematically and variation of dose distributions due to inhomogeneous tissues and sloping skin surfaces were completely compensated. 4. The electron beams, using the scatters; i.e., gold, tin, copper, lead, aluminium foils, were adequately diffused and minimizing the bremsstrahlung X-ray induced by the electron energy, irradiation field size and material of scatterers, respectively. 5. Inproving of the dose distribution from the methods of pendulum, slit, grid and focusing irradiations, the therapeutic capacity with limited electron energy could be extended.

• 대한방사선치료학회지
• /
• 제2권1호
• /
• pp.75-80
• /
• 1987

Intraoperative Radiation therapy (IORT) is a cancer treatment modality in which resectable masses or organs are removed surgically and residual cancer calls are sterilized by irradiation with a single massive dose during while patient is still anesthetized. Because it is possible that the turner mass can be visualized directly at the time of surgical exploration, tumor volume can be determined more precisely and at the same tin e sensitive adjacent structures can be pulled aside from the irradiation. With these theoretical advantages as compare to conventional external irradiation, IORT can improve the therapeutic ratio of tumor control to normal tissue injury. Yonsei cancer center initiated a pilot study of multidisciplinary IORT program in february of 1986 for the fist attempt in Korea. IORT Was performed in 7 patients with stomach cancer by using existing NELAC-1018 Linear Accelerator treatment room as a surgical suite. IOTR team included department of surgery, Department of Anethesiology, Department of Clinical pathology, operating room nursing personal and Department of radiation oncology.

• 대한방사선치료학회지
• /
• 제2권1호
• /
• pp.31-40
• /
• 1987

In the case of designing a high dose rate remote controlled afterloading treatment room with existing hospital facilities. We must construct the effective protective barriers so as to reduce the primary and scattered radiation up to the maximum permissible dose level. It is difficult to reinforce the barrier thickness of the shielding requirements because of the limited space and the problem of the existing building structure at the surrounding area. Therefore we can reduce the intensity of primary radiation to the required degree at the location of interest with installing the appropriate I shaped Pb barriers between the radiation source and the shielding wall of the concrete. As a result, it was possible to reduce the intensity of the primary radiation below the M.P.D level by using additional Pb barriers instead of increasing thickness of concrete wall.

• Journal of Radiation Protection and Research
• /
• 제14권2호
• /
• pp.45-50
• /
• 1989

원자력병원 싸이클로트른 중성자선(中性子線) 치료실의 방사선 준위(準位)를 측정함으로써 방사선 안전도를 검토하여 보았다. 중성자선 치료실내 방사선 노출은 주로 isocentric gantry에 내장된 중성자선 표적(標的)과 조사야(照射野)를 결정하는 collimator의 방사화(放射化)로 인한 잔류방사능(殘留放射能) (remanent radioactivity)에 의해 결정 된다. 측정결과 선량율(線量率)은 과다하지 않았고 개인 집적선량(集積線量)도 허용치 이내였다. 방사선 작업종사자로서의 의료기사는 환자치료 시 매 조사(照射) 완료 직후부터 5분간 멸살(滅殺)시간을 갖도록 조치하였다.

• Nuclear Medicine and Molecular Imaging
• /
• 제41권3호
• /
• pp.218-225
• /
• 2007

목적: 이 연구에서는 갑상선 암 수술 후 방사선요오드-131 치료를 받은 환자가 방사선 안전 퇴원 기준에 따라 즉시 퇴원 했을 때 환자의 가족이 받는 방사선량을 측정하여 정부의 허용범위와 비교하고자 하였다. 대상 및 방법: 의사가 설명한 방사선 안전지침을 이해하고 그대로 준수하기로 동의한 11명의 외래 환자에게 3.70 - 5.55 GBq의 NaI-131을 투여하고 가족과 환자가 생활하는 방 주변의 방사선량을 측정하였다. 결과: 환자의 가족이 받은 최대 방사선량은 정부의 허용범위 보다 훨씬 적은(5% 이내) 것으로 나타났다. 결론: 본 연구자들은 외래환자 I-131 치료가 안전하다는 것을 확인하였다. 따라서 외래환자 I-131 치료를 통해 격리 시설부족으로 인한 치료지연을 줄일 수 있고, 앞으로 갑상선 암환자 치료 관리에 도움을 줄 수 있을 것으로 확신한다. 또한 환자와 정부의 의료비용 절감 효과도 기대된다.

• 한국방사선학회논문지
• /
• 제10권3호
• /
• pp.171-180
• /
• 2016

본 연구는 고 에너지 방사선 조사에 기인된 방사선치료실 내 오존 농도의 변화를 비교 분석하고자 하였다. 이를 위하여 치료실 주변 대기 중 오존 농도와 치료실 내 배경 오존 농도를 분석하여 고 에너지 방사선 조사에 기인된 치료실 내 평균 오존 농도를 비교하였다. 치료실 내 배경 오존 농도는 평균 $17.4{\pm}7.9ppb$로 방사선치료실 주변의 대기 중 오존 농도(평균 $36.8{\pm}22.3ppb$)보다 약 50% 정도 통계적으로 유의하게 낮게 나타났다(p<0.05). 고 에너지 방사선 조사에 기인된 치료실 내 오존 농도는 방사선이 조사됨과 동시에 배경 오존 농도의 약 2배 수준으로 급격하게 증가되었으며 조사시간이 증가함에 따라 기울기가 일정한 증가 추이를 보이다가 약 130초에서 180초 부근에서 최대 오존 농도를 이루고 점차 포화되는 경향을 보였으며 배경 오존 농도로 감소하는데 소요되는 시간은 약 10분 이상이었다. 본 연구 결과를 토대로 고 에너지 방사선 조사에 기인된 방사선치료실 내 오존 농도는 후각을 자극하는 오존의 특이한 냄새를 맡거나 순간적인 호흡 곤란과 마른기침으로 가슴 통증 등의 신체적 증상이 나타날 수 있는 수준으로 밀폐된 방사선치료실에서 고농도 오존에 장시간 노출될 경우 폐 질환을 악화시킬 수 있기 때문에 각별한 주의가 요구된다.

• Journal of Radiation Protection and Research
• /
• 제48권2호
• /
• pp.100-106
• /
• 2023

Background: As breast tissue expanders consist of metallic materials in the needle guard and ferromagnetic injection port, irradiation can produce radioactivation. Materials and Methods: A CPX4 (Mentor Worldwide LLD) breast tissue expander was exposed using the Versa HD (Elekta) linear accelerator. Two photon energies of 6 and 10 MV-flattening filter free (FFF) beams with 5,000 monitor units (MU) were irradiated to identify the types of radiation. Furthermore, 300 MU with 10 MV-FFF beam was exposed to the CPX4 breast tissue expander by varying the machine dose rates (MDRs) 600, 1,200, and 2,200 MU/min. To assess the instantaneous dose rates (IDRs) solely from the CPX4, a tissue expander was placed outside the treatment room after beam irradiation, and a portable radioisotope identification device was used to identify the types of radiation and measure IDR. Results and Discussion: After 5,000 MU delivery to the CPX4 breast tissue expander, the energy spectrum whose peak energy of 511 keV was found with 10 MV-FFF, while there was no resultant one with 6 MV-FFF. The time of each measurement was 1 minute, and the mean IDRs from the 10 MV-FFF were 0.407, 0.231, and 0.180 μSv/hr for the three successive measurements. Following 10 MV-FFF beam irradiation with 300 MU indicated around the background level from the first measurement regardless of MDRs. Conclusion: As each institute room entry time protocol varies according to the working hours and occupational doses, we suggest an addition of 1 minute from the institutes' own room entry time protocol in patients with CPX4 tissue expander and the case of radiotherapy vaults equipped with a maximum energy of 10 MV photon beams.

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2002년도 Proceedings
• /
• pp.180-182
• /
• 2002

A Proton Therapy Center was established this year in National Cancer Center, Korea. We chose IBA of Belgium as the vendor of the equipment package. A 230 MeV fixed-energy cyclotron will deliver proton beams into two gantry rooms, one horizontal beam room, and one experimental station. The building for the equipment is currently under design with a special emphasis on radiation shielding. Installation of equipments is expected to begin in September next year starting with the first gantry, and the acceptance test will be performed about a year later. To generate therapeutic radiation fields the wobbling method will be a main treatment mode for the first gantry. A pencil beam scanning system on the other hand will be equipped for the second gantry relying on the availability at the time of installation. The beam scanning with intensity modulation adapted will be a most advanced form in radiation therapy known as IMPT. Some details on the project progress, scope of the system, and design of building are described.

• The Journal of Korean Physical Therapy
• /
• 제12권2호
• /
• pp.69-82
• /
• 2000

Physical therapists are exposured to radio-and microwave-frequency electromagnetic radiation by operating electrotherapy units. So there is few protection system in physical therapy room. Clinical pathology room and so on where various kins of electromagnetic instruments is used in hospital while protection failities like protection wall or protection glass is being used only in radiological room to reduce the damage of radiation. Acoording to Larsen's survey on female physical therapist in denmark. it was said that the percentage of congenital malfornation was $3.6\%$ and cadiac malformation made up $0.7\%$. It is likely that effect of electromagnetic fields on the result cannot be ruled out. Rita ouellet-Hellstron and Walter F. Steward insisted that the danger of abortion increase in the case of pregnant femeal physical therapist exposured to microwave diathermy. The intention of our study is arousing the necessity of microwave protection in P.T room and finding the proper method for physical therapist safe. The results of this study were as follows: 1. Each electrotherapy units are occurrenced the electromagnetic fields, and specially amply occurrenced in H.P,I.C.T 2 unit operating, M.W.D unit head on parallel, S.W.D unit head on parallel. all electrotherapy units are operating. 2. There were electric fields mount are consideration to species of electrotherapy units(p<.05). 3. There were magnetic fields mount are consideration to species of electrotherapy units(p<.05). 4. There were electric fields mount are consideration to distance of electrotherapy units(p<.05). 7. There were magnetic fields mount are consideration nut to distance of electrotherapy units(p>.05). 8. Before and after protection on magnetic fields mount are consideration to all distance(0m, 0.3m, 1m, 3m, 5m)(p<.05) 9. Before and after protection on electric fields mount are consideration to 0m, 1m, 3m distance(p<.05), and consideration not to 0.3m, 5m distance(p>.05) 10. After protection fellow the each electrotherapy units. distance, intencity to electromagnetic fields are reduced(p<.05).

• Journal of Radiation Protection and Research
• /
• 제6권1호
• /
• pp.34-40
• /
• 1981

방사선 치료를 위한 의료용 13 MeV 선형가속기를 설치 사용함에 따라 종사자에 대한 피폭방어를 비롯한 제반 설비구조의 설계가 중요하므로 저자들은 방사선 차폐벽과 시설구조를 법에 정해진 최대허용선량을 초과하지 않도록 계산하여 건축했으며 고에너지 선형가속기를 가동한 이후 실재 누출선량과 종사자의 피폭량을 측정하여 상호 검토하였다. 1) 방어벽의 계산은 NCRP #34 (1970)을 기초로 하였으며 이것이 가장 간단한 방법이고 경제적이었다. 2) 가속기 가동이후의 차폐벽으로부터 누출된 선량측정치는 계산에 의해 계획된 누출선량치의 약 $\frac{1}{5}$로 줄었으며 이는 치료환자의 수와 가장 안전한 수치를 사용했기 때문이었다. 3) 가속기에 의하여 방사선을 발생시키고 있는 동안 출입문 밖과 조종실 내에서의 누출선량율은 2-10mR/hr이었다. 4) 장시간 방사선을 발생시키거나 공기 조절장치의 성능이 약해졌을 때 치료실내의 오존냄새가 예측 의외로 심하였다.