[Evaluation of quality assurance program in high dose rate remote after-loading brachytherapy].
In the past 9 years, we have routinely used high-dose-rate remote afterloading systems, a Toshiba RAL-302-2 remote afterloading system and a self-fabricated Ir-192 system, for radiation therapy of various cancers, particularly cancers of the uterine cervix and nasopharynx. The frequency of using these two systems is more than 30 times per week. These machines can deliver high-dose radiation (300-1000 cGy) to a specifically planned target on the patient in a few minutes, therefore, the performance of the systems requires well planned dosimetry and quality control assurance in order to achieve effective therapeutic results and ensure safety of the patient under treatment. Any malfunction of the machines may cause over-radiation that exceeds a planned dose to the patient, and any distortion in the distribution of a planned dose may give an unexpected high dose of radiation to the therapist operating the machines. Hence, a quality assurance program must be enforced regularly to avoid or minimize any possible accidents. Based on information and recommendations reported in the literature, as well as from our own experience, we set up a program of routine checks to correct and adjust the machinery conditions and to ensure the optimum operational status of the equipment on a weekly, monthly, semiannual and annual basis. In checking the Co-60 machine, we found that the rate of occurrence for abnormal source position was 3.9% and that for the timer was 2.8%. In the Ir-192 machine checks, abnormal conditions were found only in the source position at the rate of 7.8%.
Lin
F J
FJ
Department of Radiation Oncology Chang Gung Memorial Hospital Taipei, Taiwan, R.O.C.
Tu
C P
CP
Chen
C S
CS
D001918:Brachytherapy / Q000379:methods / Q000592:standards*; D006801:Humans; D015397:Program Evaluation; D011785:Quality Assurance, Health Care; D011879:Radiotherapy Dosage