J Radiat Prot > Volume 11(1);1986 > Article
 $^{60}Co$ 치료장치의 선원 구동상의 문제점 강위생; Trouble in Source Driving System of a $^{60}Co$ Teletherapy Unit Kang, Wee-Saing; ABSTRACT An asymmetry in dose profile of a $^{60}Co$ teletherapy unit was found by means of water-phantom measurement. The reason of that trouble was confirmed to be the abnormal 'ON' position of the source, which is resulted from the high friction between contiguous surfaces of the spring for driving the source to 'OFF' position. Lubrication in the spring improved the mobility a little, but was not a radical repair. The radical repair was to replace the old spring by new one. Periodic maintenance for source driving system and periodic measurement of field symmetry are required for prevention of abnormal 'ON' position of $^{60}Co$ source.
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