Thesis (MSc.(Med)(Physics))--University of Limpopo, 2010. / Key words: Diagnostic reference levels (DRL), entrance surface dose (ESD), thermoluminescence dosimetry (TLD) Introduction: Diagnostic reference levels (DRL‟s) are defined as a dose level set for standard sized patients or standard phantoms and are not for individual exposures and individual patients and are an efficient standard for optimizing the radiation protection of patients and are practically useful for more common examinations. The International Atomic Energy Agency (IAEA) recommends entrance surface dose (ESD) as DRL‟s in diagnostic radiology and are establish using a TLD on a patient/phantom surface. Aim: To estimate entrance surface dose for different X-ray procedures. Objectives: The objective of this study is to develop the diagnostic reference levels by assessing the dose received by a patient in radiographic exposure. This was achieved using different X-ray techniques to estimate the entrance surface dose for different examinations. Method: The study was conducted at the Dr George Mukhari hospital using 5 different X-ray machines. Before the study commenced quality assurance was done on the machines. The following examinations were considered: Cervical spine (AP), cervical spine (LAT), Skull (AP), Skull (PA), Abdomen (AP), Pelvis (AP), Lumber spine (AP), Lumber spine (LAT), Chest (PA) and Chest (LAT). Thermoluminescence lithium fluoride (LiF) (TLD-100, 3.16 X 3.16 X 0.9 mm3, Harshaw) and the Rando phantom were used to estimate the ESD‟s in mGy. Three TLD‟s were mounted on the top of the phantom in the centre of X-ray beam, external to the organ/tissue being imaged. The average dose was calculated for each radiograph and for each examination. The following technique factors were recorded: tube kilovoltage, focus-to-surface distance, focus-to-film distance, time and mA. vi Results: The mean ESD‟s measured at the centre of X-ray beam on the surface of the phantom for the following examinations are: Cervical spine (AP), 2.99 (± 0.26) mGy; Cervical spine (LAT), 3.23 (± 0.34) mGy; Skull (PA), 3.50 (±0.37) mGy; Skull (LAT), 2.60 (± 0.26) mGy; Abdomen (AP), 4.18 (± 0.40) mGy; Pelvis (AP), 3.96 (± 0.33) mGy; Lumber spine (APS), 4.72 (± 0.39) mGy; Lumber spine (LAT), 8.56 (± 0.67) mGy Chest (PA), 0.72 (± 0.27) mGy and Chest (LAT), 1.03 (± 0.45) mGy. Conclusion: The results of the individual exposure and the overall results of each examination were lower than reported in the literature except for the chest (PA). The determination of patient dose and the comparison with the international DRL‟s are an important factor in the optimization process in diagnostic radiology and it is of special concern for the patient‟s protection. The baseline of diagnostic reference levels for the Dr George Mukhari hospital has been established and the results obtained could be useful for future patient dose measurements in diagnostic radiology Department at the Dr George Mukhari hospital.

The practice in the department of nuclear medicine requires the involvement of radiation protection with care of patients and occupational safety of radiation workers. Nuclear medicine involves the handling of radioactive substances that may cause external or internal irradiation of workers. The amount of the dose depends on the type of radionuclide, the amount of energy, the work performed by the worker within the department. Patients or staff may be exposed to the external or internal irradiation. The topic of this thesis is the analysis of the current state of radiation protection in the department of nuclear medicine according to the new legislation. The part of the work is the evaluation of monitoring of workers and patients. The research results of the average annual effective dose of total body irradiation at radiation workers ranged from 1.35 to 1.73 mSv, monthly ranged from 0.1? 0.65 mSv. The average annual equivalent dose of Hp (0,07) ranged from 1.15 to 117.68 mSw. The lowest monthly Hp (0.07) was 0.07 mSw and the highest one was 19.92 mSw. At SSK-treated patients the doses applied were 4% lower than diagnostic reference level and the dose at DSSL-treated patients was 22% less than DRU. In conclusion, it was found that the values from personal dosimeters were below the limit and in the case of finger dosimeters in two cases the values were above the examination level. The values of other workers were below the monitoring level during the monitored period. The applied doses of radiopharmaceuticals were less in the observed group of patients than the established diagnostic reference level. On the basis of the presented results it can be stated that radiation protection is in the Department of Nuclear Medicine of Znojmo Hospital f.o, secured in accordance with the applicable legislation.

The aim of this study is to determination of local diagnostic reference levels for radiodiagnostic examination in the General Teaching Hospital in Prague. Local diagnostic reference levels are used for an evaluation of radiation load which patients receive during medical examinations of specific parts of the human body. The evaluation can be on the level of a hospital and its department or on the level of concrete X-ray machine. The theoretical part describes a ionizing radiation, including its interaction with matter, creating, formation of radiodiagnostic image, legislation during optimization of radiodiagnostic examination, radiological protection and determination of values for radiation dose. The practical part describes the determination of local diagnostic reference levels with the help of entrance surface kerma and the median dose in the mammary gland. Both of these variables are relevant for determination of the risk of adverse effects of ionizing radiation which is applied during radiographic examination. Data for this study was collected with the help of operating diaries and PACS system. It has been rated twenty-six kinds of examinations from twelve mobile and nine stationary (including two mammographs) X-ray machines. All resulting values were statistically processed and compared with...