Patient dosimetry in diagnostic radiology

The objective of this work is to assess patient organ doses, effective doses and entrance surface doses in conventional diagnostic radiology procedures for standard adult patient. The survey consists of measurements of doses delivered to 239 patients in nine types of X-ray examinations. Three types of data were collected: X-ray machine data, patient data, and output measurements. Entrance surface dose was assessed based on the survey data and subsequently, using conversion coefficients, the organ doses and effective doses were calculated. Values of the entrance surface dose and the effective dose were estimated to be 0.4 to 5.8 mGy and 0.03 to 3.00 mSv for different examinations. Derived doses were compared with recommended general diagnostic reference levels. The impact of examination parameters on dose values was discussed. Except for posterior-anterior chest examination, all estimated doses are lower than stated reference levels. Survey data are aimed at helping development of national quality control and radiation protection programmed for medical exposures

Radiation dose and risk assessment in hysterosalpingography

Hysterosalpingography is an important diagnostic method for the evaluation of the female reproductive tract involving the exposure of patients to ionizing radiation. The irradiation of ovaries is unavoidable and radiation exposure of the patient and the associated radiological risk for the foetus and born child during the period of growth should be considered, as well. The purpose of this work is to evaluate organ and patient doses and radiation risks during hysterosalpingography procedures performed in a dedicated gynecological hospital. The entrance surface air kerma was measured for a total of 31 patients during hysterosalpingography. Based on the results obtained, the radiogenic risk for hereditary effects and cancer induction was estimated. The patient dose levels are in the range of 3-15 mGy, with a median value of 10 mGy, in terms of entrance surface air kerma. Estimated median ovarian and uterus doses are 1.7 and 2.3 mGy, respectively. The risk for fatal cancer and hereditary effects is estimated to be 5.5×10-5 and 3.4 ×10-6, respectively. Although low compared to the natural incidence of genetic effects and cancer, it can be elevated in cases of prolonged or repeated procedures or procedures where the non-optimized protocol is used

Physical and technical aspects of quality assurance in mammography in the Republic of Srpska

Breast cancer is the most frequent malignant neoplasm affecting the female population. In order to reduce its morbidity and mortality rate, a mammography screening campaign has been established in both entities of Bosnia and Herzegovina. In this paper, a brief survey is given on the mammography screening practice in the Republic of Srpska. As an illustration, results of measurements of technical parameters, including mean glandular dose, for 31 mammography units are presented. Large fluctuations in dose among different measuring sites were found, unacceptable not only from the standpoint of mammography screening, but in clinical mammography as a whole. Subsequently, a series of quality control tests and corrective measures throughout the mammography imaging chain are proposed, in line with international guidelines and newly promulgated national legislation. Dose optimization and image quality improvement are the first and foremost goals to be achieved in order to setup a successful mammography screening program

Patient doses in computed tomography: An assessment of local diagnostic reference levels in a large teaching hospital

This paper presents an estimation of local diagnostic reference levels in computed tomography in a large teaching hospital. Local diagnostic reference levels, expressed in terms of volume weighted computed tomography dose index and dose-length product, were estimated for three most frequent adult computer tomography examinations: head, abdomen and pelvis combined, and thorax. The established local diagnostic reference levels values were similar or slightly higher compared to the available guidelines, indicating the possibility for optimization of current practice. Analyzing the protocols used here and recently published studies on dose reduction in computed tomography, a dose-reduction technique, was proposed to decrease tube current values in all three examinations. However, the optimization should be restricted only to standard-sized patients

Radiation doses in cerebral perfusion computed tomography: patient and phantom study

The purpose of this study was to investigate radiation doses in cerebral perfusion computed tomography (CT) examination. As a part of routine patient monitoring, data were collected on patients in terms of the skin dose and CT dose index (CTDIvol) and dose-length product (DLP) values. For the estimation of the dose to the lens a phantom study was performed. Dose values for skin and lens were below the threshold for deterministic effects. The results were also compared with already published data. For better comparison, the effective dose was also estimated. The values collected on patients were in the ranges 230680 mGy for CTDI and 21202740 mGy cm for DLP, while the skin dose and estimated effective dose were 340800 mGy and 4.96.3 mSv, respectively. These values measured in the phantom study were similar, while the doses estimated to the lens were 53 and 51 mGy for the right and left lens, respectively

Intercomparisons as an important element of quality assurance in metrology of ionising radiation

Intercomparisons are important activities performed to ensure that the services provided by calibration laboratories to end-users follow internationally accepted standards. Ionizing radiation dosimetry intercomparisons are usually of two types - postal thermoluminescent dosimeter intercomparisons and ionization chamber calibration intercomparisons. In this paper, both types of intercomparisons are analysed together with the results of seven years of participation in such intercomparisons. Several discrepancies were discovered as a result of intercomparisons analysis and the resolution of the discrepancies was discussed. [Projekat Ministarstva nauke Republike Srbije, br. III43009: New Technologies for Monitoring and Protection of Environment from Harmful Chemical Substances and Radiation Impact