Assessment of Co-57 image uniformity tests for gamma camera system

Abstract

Extracorporeal shock wave lithotripsy is considering the extensive world external treatment process for renal, uretric , bladder and gallbladder stones. This procedure is usually followed up by using x-ray fluoroscopy devices as localizer, the reason is that to optimize the absorbed dose of patients according to the recommendations of international organizations; the aim of this study is to measure the entrance surface dose and the probability of carcinogenesis regarding to x-ray fluoroscopy irradiating during ESWL. The study was applied in Al-Naileen diagnostic center (Group 1, 50 patient) and in Al-Khartoum advance diagnostic center (Group 2, 25 patients), the classification of patients was depending on the type of the lithotripter. The entrance surface dose measurements were done by using thermoluminescence dosimeter (TLDs) GR200A LiF. The mean entrance surface dose and mean effective dose were (0.38 mGy) and (0.34 mGy) for group1 and 2 respectively, the measured organ dose were (0.16 mGy), (0.02) and (0.01) for kidneys, intestines and ovaries. As it was observed Group1 was irradiated to higher dose than Group 2 that’s because of the x-ray fluoroscopy equipment in Group 1 has no ability to change the orientation of the machine without exposing the patient to radiation, thus the duration of irradiating is extended and as a result then increasing the entrance surface dose. The results show that the probability of carcinogenesis due to irradiating to the measured amounts of radiation exposures is a tiny value (1 for million patient) but the main biological effect is occur due to the cumulative impact of radiation. In addition the study insures that there is a correlation between the weights, irradiating factors and absorbed doses. As a result guiding charts, training courses for technologist and a strong quality assurance program were recommended to optimize the ESD for patients.