Establishing national diagnostic reference levels (DRLs) for computed tomography in Egypt.

OBJECTIVES: To establish national diagnostic reference levels (DRLs) in Egypt for computed tomography (CT) examinations of adults and identify the potential for optimization. METHODS: Data from 3762 individual patient's undergoing CT scans of head, chest (high resolution), abdomen, abdomen-pelvis, chest-abdomen-pelvis and CT angiography (aorta and both lower limbs) examinations in 50 CT facilities were collected. This represents 20% of facilities in the country and all of the 27 Governorates. Results were compared with DRLs of UK, USA, Canada, Japan, Australia and France. RESULTS: The Egyptian DRLs for CTDIvol in mGy are for head: 30, chest (high resolution): 22, abdomen (liver metastasis): 31, abdomen-pelvis: 31, chest-abdomen-pelvis: 33 and CT angiography (aorta and lower limbs): 37. The corresponding DRLs for DLP in mGy.cm are 1360, 420, 1425, 1325, 1320 and 1320. For head CT, the Egyptian DRL for CTDIvol is 2-3 times lower than the DRLs from other countries. However, the DRL in terms of DLP is in the same range or higher as compared to others. The Egyptian DRL for chest CT (high resolution) is similar to others for DLP but higher for CTDIvol. For abdomen and abdomen-pelvis DRLs for CTDIvol are higher than others. For DLP, the DRLs for abdomen are higher than DRL in UK and lower than those in Japan, while for abdomen-pelvis they are higher than other countries. CONCLUSION: Despite lower DRLs for CTDIvol, an important consistent problem appears to be higher scan range as DRLs for DLP are higher.

Survey on impact of regulations on radiation safety and development of radiation safety culture in 25 countries.

The purpose of this work was to assess the: (a) impact of regulations on radiation safety and development of radiation safety culture, (b) perceived safety level in the participating facilities, (c) future needs regarding strengthening of regulations, patient dose consideration, and exposure tracking, in different countries around the world. Appropriate questionnaires probing the above-mentioned themes were sent to radiologic professionals working in healthcare facilities. A total of 257 responses from 25 countries were received and analyzed. Average scores for the three different sections/themes of the questionnaire ranged from 64.6% to 74.9%. Higher scores indicated stronger agreement of the survey participants with the theme in question. Statistical comparisons among different professional groups revealed that professionals in developing countries perceived regulations to be significantly more important for improving safety than their counterparts in developed countries did. Radiologic professionals believe that regulation enhances radiation safety and the development of safety culture. However, there is still room for improvement regarding the implementation of regulatory tools. Safety levels were perceived to be satisfactory, and future needs point toward strengthening of regulations regarding patient dose control, patient dose consideration, and patient exposure tracking. The results of this study should be interpreted keeping possible selection bias in view.

Status of radiation protection in various interventional cardiology procedures in the Asia Pacific region.

OBJECTIVE: Increasing use of interventional procedures in cardiology with unknown levels of radiation protection in many countries of Asia-Pacific region necessitates the need for status assessment. The study was part of an International Atomic Energy Agency (IAEA) project for achieving improved radiation protection in interventional cardiology (IC) in developing countries. DESIGN: The survey covers 18 cardiac catheterisation laboratories in seven countries (Bangladesh, India, Malaysia, Myanmar, Singapore, Thailand and Vietnam). An important step was the creation of the 'Asian network of Cardiologists in Radiation Protection' and a newsletter. Data were collected on: radiation protection tools, number of IC laboratories, and annual number of various IC paediatric and adult procedures in the hospital and in the country. Patient radiation dose data were collected in terms of Kerma Area Product (KAP) and cumulative dose (CD). RESULTS: It is encouraging that protection devices for staff are largely used in the routine practice. Only 39% of the angiographic machines were equipped with a KAP meter. Operators' initial lack of awareness on radiation-protection optimisation improved significantly after participation in IAEA radiation-protection training. Only two out of five countries reporting patient percutaneous coronary intervention radiation-dose data were fully within the international guidance levels. Data from 51 patients who underwent multiple therapeutic procedures (median 2-3) indicated a total KAP reaching 995 Gy.cm(2) (range 10.1-995) and CD 15.1 Gy (range 0.4-15.1), stressing the importance of dose monitoring and optimisation. CONCLUSIONS: There is a need for interventional cardiology societies to play an active role in training actions and implementation of radiation protection.

Unintended exposure in radiotherapy: identification of prominent causes.

BACKGROUND AND PURPOSE: Unintended exposures in radiotherapy are likely to occur when certain conditions that favour such exposures exist. Based on the frequency of occurrence of various causes of 100 events of unintended exposures in radiotherapy as derived from the analysis of published reports, a checklist for assessing the vulnerability of radiotherapy facilities for potential accidents has been prepared. The list presents items to be considered for safety critical assessments of a radiotherapy department for the improvement of patient safety and the entire radiotherapy processes. MATERIALS AND METHODS: The resources used for this paper consist of 100 unintended radiotherapy exposures and were derived from existing published reports. The analysis was performed by forming two templates: one consisting of 10 initiating events and another of 35 contributing factors. RESULTS: Four most prominent initiating events were identified and together accounted for about 70% of all the unintended exposure events. Ten most prominent contributing factors were also identified and together accounted for about 70% of all the radiotherapy unintended exposure events covered under this study. CONCLUSION: With this knowledge of high frequency of occurrences, the identified four prominent initiating events and the 10 most prominent contributing factors must be checked and dealt with as a matter of priority when assessing the safety of a radiotherapy facility. A simple checklist for checking the quality assurance programmes of a radiotherapy department for every aspect of the design and delivery of radiation have been provided.

Tumor marker CA-125 as an evaluator and response indicator in ovarian cancer: its quantitative correlation with tumor volume.

BACKGROUND: The tumor marker Cancer Antigen 125 (CA 125), though not ovarian cancer specific, is widely used for the evaluation of suspected and under-treated ovarian cancer. Many studies show that serum CA 125 level demonstrates ovarian tumor burden and its response, but they lack quantitative correlation between the two. Instead, they rely on clinical or radiological assessment of gross tumor burden. This study examines ovarian tumor volumes and corresponding serum CA 125 values before and during chemotherapy. MATERIALS/METHODS: [corrected] Ovarian tumor volume was measured by CT scans at pre-chemotherapy and after each cycle of chemotherapy in 15 patients. Blood serum CA 125 was determined on the days of CT scans using a one-step immunoenzymatic assay. RESULTS: There was no statistically significant correlation (r = 0.18, p > 0.05) between ovarian tumor volumes and CA 125 among patients at pre-chemotherapy or any subsequent time. In individual patients, the reduction or increase in tumor volume correlated with the corresponding CA 125 values during chemotherapy in 85% (12 out of 14) of patients. Mean CA 125 halving time was 44.1 days, which correlated with tumor halving time (r = 0.63, p < 0.05). CONCLUSIONS: Values of CA 125 cannot be used for comparison of ovarian tumor mass among patients. However, serial estimation of CA 125 in individuals is fairly reliable in terms of the course of the tumor. CT scan is a more informative response indicator, but it is costly and hence may be supplemented by the easy and economical CA 125 estimation.

Potential of CT-scan based tumor volume as a response indicator in chemotherapy of advanced epithelial ovarian cancer.

BACKGROUND: Response prediction in patients undergoing chemotherapy for ovarian cancer is an important issue, since the cure rate is only about 15-20%. We attempted to develop a semi-empirical model to predict response in individual cases after the first cycle of chemotherapy. MATERIAL/METHODS: This prospective study included 51 cases of advanced ovarian cancer. A method was standardized to estimate ovarian tumor volume accurately from CT scan films. This permits the inclusion of patients who have undergone CT scan elsewhere. Patients underwent 4-6 cycles of chemotherapy and tumor volume was estimated after each cycle. This yielded a tumor regression curve for each patient. RESULTS: Percent reduction in tumor volume after the first chemo-cycle was a significant prognostic factor in multivariate analysis. Depending upon the rate of regression patients could be classified into Fast Regressing FR (n=29) and Moderately Regressing MR (n=16), whereas 6 patients showed Progressive Disease (PD) despite ongoing chemotherapy. The median survivals for the FR, MR and PD groups were 29.3, 18.9 and 8.5 months respectively. We found that 'percent reduction in volume after first chemo-cycle' could categorize a patient as FR/MR/PD correctly in 94.1% of cases. This parameter could also detect 5 out of 6 inherently resistant PD cases, who would otherwise undergo further chemotherapy, since early detection of resistance by clinical monitoring is quite difficult. CONCLUSIONS: An individual patient at risk for shorter survival and with inherent drug resistance can be identified after the first cycle of chemotherapy.