This paper estimates backscattered radiation doses at patient's positioning level (exposed object) using different X-ray tubes. The effects of different exposure sittings (X-ray tube voltage, exposure intensity, exposed area, dosimeter position, and distance between X-ray tube and imaged object surface) on backscattered radiation doses are estimated using different dosimeters and x-ray units. The quantity of recorded backscattered radiation dose -which reflects from patient's table or bucky to image receptor and exposed patient -is determined by the position of dosimeter between exposed object's table or bucky and X-ray tube according to backscatter angle, at higher backscattered angle, the dosimeter records more backscattered dose. The results showed that, increase in kVp, exposure intensity, and exposed area led to a concomitant increase in the quantity of backscattered radiation, whereas the Increase in distance between X-ray tube (source) and imaged object surface reduces the amount of backscattered radiation dose. As well as, there is no remarkable difference in recorded backscattered dose due to the position of X-ray tube or the direction of incident X-ray photons.

Radiation dosimeters exhibit several performance properties characterized by their precision and accuracy, linearity, dose and energy dependence, stability and spatial resolution. However, these characteristics may not be satisfied by all dosimeters. The dosimetric performances of Instadose and Thermolumniscence dosimeters (TLDs) which are the two most commonly used personal dosimeters in health care institutions were comparatively assessed under clinical settings in which a GE haulum XR 6000 X-ray machine with a frequency of 50/60 Hz was used to serially irradiate Mironinstadose and TLD 100H badges to a controlled exposure factors and readings of absorbed doses for instadose were obtained from a portable computer with internet access, while that of TLDs was obtained through heating using Harshaw 4500 automatic TLD reader at Center for Energy Research and Training (CERT), Zaria. The dose equivalent quantities measured were; Hp (10), Hp (3) and Hp(0.07) all in mSv, representing deep, eye lens and shallow doses respectively. Results of measured doses ranged between 0.74 mSv to 22.96 mSv for instadose and 0.71 mSv to 35.42 mSv for TLD badges in all performance tests conducted. Homogeneity results were 9% and 12%, reproducibility was 7.2% and 3.9% while percentage deviation for linearity test was below 10% for both instadose and TL dosimeters. The performance tests results of instadose and TL dosimeters were assessed based on the criteria of the International Electrotechnical Commission (IEC) 1066 standard. The assessment revealed good performance indices within the requirement of the IEC standard. However, TL dosimeters demonstrate high sensitivity in the self-irradiation test exceeding the standard mSv values.