A comparative study of quality control in diagnostic radiology.

The main objective of this comparative study was to evaluate the national quality assurance program for X-ray diagnostic radiology in Syrian governmental hospitals. Two periods were covered in this study, the first period was from 1986 to 1998 (52 hospitals and 149 X-ray machines were considered) and the second period from 1999 to 2005 (41 hospitals and 95 X-ray machines were considered). Most of the X-ray machines studied were within the acceptable performance, but few machines needed recalibration for some parameters. Considerable improvement of about 50% was reported in the second period. This improvement could be attributed to the establishment of an effective National Regulatory Authority in Syria in 1998 that introduced and gradually enforced the quality assurance requirement for X-ray equipment as part of the licensing process and to the relatively newer X-ray machines covered in the second period.

Monte Carlo determination of the lead equivalent for Syrian building bricks for diagnostic x ray.

The uncertainty band associated with the transmission curve for 100 kVp x ray in lead was determined using Monte Carlo methods and the sensitivity analysis approach. All uncertainty sources (statistical, systematical and the uncertainties arising from the diversity of x-ray tubes) were taken into account. The transmission of 100 kVp x ray in Syrian building bricks was then computed together with the uncertainty associated with it. Finally, the lead equivalent thicknesses for 10, 15, and 20-cm-thick bricks were estimated. The results are in good agreement with experimental results. This study recommends, as a rule of thumb, to use the lead-equivalent values of 0.5, 0.75, and 1.0 mm for the 10, 15, and 20-cm-thick building bricks, respectively.

Image quality and dose in mammography in 17 countries in Africa, Asia and Eastern Europe: results from IAEA projects.

PURPOSE: The objective is to study mammography practice from an optimisation point of view by assessing the impact of simple and immediately implementable corrective actions on image quality. MATERIALS AND METHODS: This prospective multinational study included 54 mammography units in 17 countries. More than 21,000 mammography images were evaluated using a three-level image quality scoring system. Following initial assessment, appropriate corrective actions were implemented and image quality was re-assessed in 24 units. RESULTS: The fraction of images that were considered acceptable without any remark in the first phase (before the implementation of corrective actions) was 70% and 75% for cranio-caudal and medio-lateral oblique projections, respectively. The main causes for poor image quality before corrective actions were related to film processing, damaged or scratched image receptors, or film-screen combinations that are not spectrally matched, inappropriate radiographic techniques and lack of training. Average glandular dose to a standard breast was 1.5 mGy (mean and range 0.59-3.2 mGy). After optimisation the frequency of poor quality images decreased, but the relative contributions of the various causes remained similar. Image quality improvements following appropriate corrective actions were up to 50 percentage points in some facilities. CONCLUSIONS: Poor image quality is a major source of unnecessary radiation dose to the breast. An increased awareness of good quality mammograms is of particular importance for countries that are moving towards introduction of population-based screening programmes. The study demonstrated how simple and low-cost measures can be a valuable tool in improving of image quality in mammography.

Survey of patient dose in computed tomography in Syria 2009.

The radiation doses to patient in computed tomography (CT) in Syria have been investigated and compared with similar studies in different countries. This work surveyed 30 CT scanners from six different manufacturers distributed all over Syria. Some of the results in this paper were part of a project launched by the International Atomic Energy Agency in different regions of the world covering Asia, Africa and Eastern Europe. The dose quantities covered are CT dose index (CTDI(w)), dose-length product (DLP), effective dose (E) and collective dose. It was found that most CTDI(w) and DLP values were similar to the European reference levels and in line with the results of similar surveys in the world. The results were in good agreement with the UNSCEAR Report 2007. This study concluded a recommendation for national diagnostic reference level for the most common CT protocols in Syria. The results can be used as a base for future optimisation studies in the country.

Survey of patient doses from conventional diagnostic radiographic examinations in Syria.

The aim of this study is to evaluate radiation doses received by adult patients undergoing eight routine common types of X-ray examination in Syria. These types cover chest PA, lumbar spine PA, lumbar spine LAT, urography, abdomen, pelvis and hip, head and shoulder. This work consisted of measurements for 926 X-ray examinations for patients in 26 governmental hospitals. The mean and third quartile of the dose area product (DAP) to each patient per examination have been measured. The corresponding average effective doses have been computed from the DAP measurement for each examination using NRPP X-Dose software. Comparison of the results was done with those from similar surveys published by the United Nation Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000, 2007). The present measurements will provide a useful baseline to establish, for the first time, national diagnostic reference levels. These results can be used in the future to evaluate the collective dose to the population from medical exposure and the radiation risks from the various radiological procedures.

Assessment of public doses due to a neutron calibration bunker.

In this work, the expected neutron and gamma doses in the populated areas outside the newly constructed neutron calibration bunker at the Atomic Energy Commission of Syria will be assessed using the Monte Carlo code MCNP-4C2. The results showed that the maximum ambient dose equivalent rate (neutrons and gammas) outside the bunker would not exceed 0.5 microSv h(-1), assuming an Am-Be neutron source of emission rate of 10(8) n s(-1). The neutron dose is approximately 10 times higher than the photon dose. Sky shine contributes by about 25-50% of the neutron dose and 7-27% of the gamma dose, depending on the location. The simulation uncertainty due to the possible variations in the simulation parameters has been given particular importance.

Paediatric CT examinations in 19 developing countries: frequency and radiation dose.

The aims of this study were to investigate the frequency of computed tomography (CT) examinations for paediatric patients below 15 y of age in 128 CT facilities in 28 developing countries of Africa, Asia and Eastern Europe and to assess the magnitude of CT doses. Radiation dose data were available from 101 CT facilities in 19 countries. The dose assessment was performed in terms of weighted CT dose index (CTDI(w)), volume CT index and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. The results show that on average the frequency of paediatric CT examinations was 20, 16 and 5 % of all CT examinations in participating centres in Africa, Asia and Eastern Europe, respectively. Eleven CT facilities in six countries were found to use adult CT exposure parameters for paediatric patients, thus indicating limited awareness and the need for optimisation. CT images were of adequate quality for diagnosis. The CTDI(w) variations ranged up to a factor of 55 (Africa), 16.3 (Asia) and 6.6 (Eastern Europe). The corresponding DLP variations ranged by a factor of 10, 20 and 8, respectively. Generally, the CTDI(w) and DLP values in Japan are lower than the corresponding values in the three regions in this study. The study has indicated a stronger need in many developing countries to justify CT examinations in children and their optimisation. Awareness, training and monitoring of radiation doses is needed as a way forwards.

Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects.

The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs. The resulting CT images were of adequate quality for diagnosis. The CTDIw and DLP data presented herein are largely similar to those from two recent national surveys. The study has shown a stronger need to create awareness and training of radiology personnel as well as monitoring of radiation doses in many developing countries so as to conform to the ALARA principle.