ABSTRACT
The aim of this study was to estimate radiation doses to patients undergoing standard radiographic examinations using Computed Radiography (CR) and Direct Digital Radiography (DDR) in two hospitals within Hamad Medical Corporation (HMC) in Qatar, and compare the results with regional and international Diagnostic Reference Levels (DRLs). Data on 3391 patients were recorded from different X-ray rooms in HMC hospitals. Entrance Skin Dose (ESD) was measured for 1046 patients for the most five common X-ray examinations (a total of 7 projections) namely: Skull, Chest, Abdomen, Lumbar Spine and Pelvis. Exposure factors such as kV, mAs and Focal to Skin Distance (FSD) were recorded for each patient. Tube Output was measured for a range of selected kV values. ESD for each individual patient was calculated using the tube output and the technical exposure factors for each examination. The ESD values were compared with some international DRLs for all types of examinations. HMC patient demographic data evaluated from this study were: average age of 39 years, average weight of 60-80 kg and mean height of 165 cm. The most procedure performed during the time of this study was chest PA (52%), and the least procedure performed was skull AP/LAT (1%) examination. The mean ESD values found to be generally lower than the published values. With exception of abdomen examinations at Hamad General Hospital (HGH), mean ESD values were found to be within the established IAEA (DRL). The mean ESD values at HGH were found to be much higher than that at Al Khor Hospital (AKH) for abdomen, Lumbar spine AP, Lumbar Spine LAT and pelvis, but generally lower than the published values.
ABSTRACT
The primary objective of this study was to measure the mean glandular dose (MGD) from craniocaudal (CC) and mediolateral oblique (MLO) views from mammography patients in Hamad Medical Corporation (HMC) in the state of Qatar and to compare them with the international guidelines levels as well as to establish Dose Reference Level (DRL) for the country by applying the quality control (QC) protocol for the Digital mammography units and to reduce the patient dose and improve the image quality. All patients data was taken from two Selenia digital mammography units for 18 months period. Quality control was implemented for the two mammography machines and corrective actions have been done for the image quality evaluation with rejected film analysis. The total number of collected patient data was 4085 mammography exams which considered as around 93% of the overall mammography procedures done in Qatar during that period. Based on the IAEA selection criteria of breast thickness between 2-7 cm and kV machine value from 26 to 33 kV, only 3280 mammography procedures satisfies the above criteria and are analysed accordingly, National Centre for Cancer Care & Research (NCCCR) 949 and Hamad General Hospital (HGH) 2331 exposures. The present study revealed that there were significant differences between the MGD values for the CC and MLO views (p <0.006). Referring to the limiting dose values in the European guidelines, the results from the two mammography units showed that 94.5% and 99.7% of the mean glandular doses are acceptable from NCCCR and HGH respectively. Due to compression devise error in the NCCCR mammography machine, the MGD for some patients became more than the acceptable values especially at small breast thickness values (0-3 cm) which it seems 0% in the acceptable range.