# 방사선(放射線) 치료(治療)의 신속정확(迅速正確)을 위한 저온용융(低溫熔融) 차폐물(遮蔽物)의 제작(製作)과 응용(應用)

• Chu, S.S. (Department of Radiology and Nuclear Medicine, Yonsei University College of Medicine) ;
• Lee, D.H. (Department of Radiology and Nuclear Medicine, Yonsei University College of Medicine) ;
• Park, C.Y. (Department of Radiology and Nuclear Medicine, Yonsei University College of Medicine)
• 추성실 (연세대학교 의과대학 방사선과학교실) ;
• 이도행 (연세대학교 의과대학 방사선과학교실) ;
• 박창윤 (연세대학교 의과대학 방사선과학교실)
• Published : 1979.07.30

#### Abstract

For accurate and easily shielding irregular shaped organ, its minimized penumbra region and a low melting point alloy 'Lead Y' and synchronizing instrument have been developed. The 'Lead Y' is the quaternary eutectic alloy and it is composed of Lead 30.0% Tin 11.5% Bismuth 48 5% Cadmium 10.0% The density of its at $22^{\circ}C$ is $9.8g/cm^3$ and the melting temperature has $40^{\circ}C\;to\;68^{\circ}C$. The thickness of 'Lead Y' for perfect shielding of Co-60 gamma ray and LINAC 10MeV x-ray is 6cm and 7cm respectively. The 'Lead Y' shielding block is casted directly on the styrofoam from which is cut with hot wire of synchronizer device. The special features and advantages of the Lead Y shielding block could be summarized as follows; 1. The shielding block for radiotherapy is rapidly processed only with boiling water and styrofoam. 2. It is not injure one's health and not danger of a fire, because of not generating of any metals vapor and evil smelling. 3. It is very effective to minimize secondary penumbra for the protection of healthy tissue from unnecessary ionizing radiation regardless of the magnification source to skin distance. 4. The HVL of the Lead Y is 1.2cm for Co-60 gamma ray and it's shielding effect is almost same as the pure lead block. 5. The hardness of Lead Y is 1.5 times higher than lead block. 6. It's reavailability is higher than lead block and then one block of Lead Y is reavailable about 30 to 40 times. 7. It is usefull for shielding of x-ray, gamma ray, beta-ray, electron and neutron radiation. 8. The materials for Lead Y are easy to acquire with reasonable price and tractable.