EVALUATION OF PATIENT ABSORBED DOSE OF CONVENTIONAL X-RAYS USING DIRECT METHOD IN SOME HOSPITALS IN PORT HARCOURT, NIGERIA

Abstract

In this work, entrance skin dose was used to evaluate patient absorption dose of conventional X-rays using a direct method in some hospitals in Port-Harcourt, Rivers State. The method was based on the guidelines established by the NBIRR protocols. Questionnaires were distributed to two (2) X-ray facilities in Port Harcourt, Rivers State with code names GHC and UPTH in order to obtain information about X-ray machines such as type, model, waveform, filtration, etc., and radiological parameters used during two common diagnostic procedures such as Kilo Peak Voltage (kVp) and Milli Ampere Times Seconds (mAs). The two types of X-ray exams considered were chest (PA) and abdomen (AP). The weight and height of each patient totaling one hundred (100) were measured and two TLD badges were used on each patient to record the patient’s dose while a TLD reader (Harshaw 6600) was used to read the chips and an oven (annealing machine) was also used to anneal the chips. Mean ESD (mGy) was estimated and compared with International Established Reference Values. It was found that the mean ESD (mGy) for chest (PA) was 1.40, which is higher than the standard values of 0.17, 0.40, and 0.30 for USA, IAEA, and NRP, respectively. While the mean ESD (mGy) for the abdomen (AP) was found to be 1.62, which was higher than the standard values of 0.56, 1.02, and 102 for the USA, IAEA, and NRP, respectively. Generally, it was observed that there was a wide variation in patient dose for the two different types of x-ray examinations, which could be attributed to several factors, such as the type of x-ray machine used, radiographic techniques.