| Partâ… Measures of Radiation Dose in Interventional Radiology Procedures Purpose: To determine patient radiation doses for interventional radiology procedures, to identify procedures associated with higher radiation doses, and to determine the effects of various parameters on patient doses. Methods: Data were collected on 405 instances of interventional radiology procedures. The radiation dose data, such as DAP (dose-area product), CD (cumulative dose), fluoroscopy time and number of images measured by using a dose system equipped in DSA (digital subtraction angiography) were obtained. Results: There were wide variations in dose and statistically significant differences in fluoroscopy time, number of images, DAP, and CD for differrence instances of the same procedure, depending on the nature of the lesion, its anatomic location, and the complexity of the procedure. For the 405 instances, observed CD and DAP correlate well overall (r=0.883, P<0.001), but correlation in individual instances is poor. The correlation between fluoroscopy time and CD (r=0.567, P<0.001) is not as good. The same is true for the correlation between fluoroscopy time and DAP (r=0.400, P<0.001). In 1% of instances (5 of 405), which were cerebral embolisation (CE), hepatic arterial chemoembolization (HACE), percutaneous transhepatic cholangial drainage (PTCD), and lower extremity vein filter placement, CD was greater than 3Gy. Conclusions: Some procedures studied can result in clinically significant radiation dose to the patient, even when performed by trained operators with use of dose-reducing technology and modern fluoroscopic equipment. CE, HACE, PTCD, and lower extremity vein filter placement are associated with a substantial likelihood of clinically significant patient dose. At minimum, patient dose data should be recorded in the medical record for these four types of procedures. These data should include indicators of the risk of deterministic effects as well as the risk of stochastic effects. Partâ…¡Comparison of Four Techniques to Estimate Radiation Dose to Skin during Interventional Radiology Procedures Purpose: Four techniques, which were fluoroscopy time, DAP, CD and entrance skin dose (ESD), used to estimate radiation risk were compared to determine whether commonly used dosimetry measurements permit reliable estimates of skin dose. Methods: Fifty patients undergoing cerebral angiography (CAG), selective bronchial artery embolization (SBAE), hepatic arterial chemoembolization (HACE), hepatic arterial infusion chemotherapy (HAIC), and internal iliac artery embolization (IIAE) were studied. Fluoroscopy time, DAP, and CD were recorded for all procedures; ESD was calculated by thermoluminescent dosimeter (TLD). The dose index, defined as the ratio between ESD and CD, was also determined. Dose index and CD were used to calculate 264 patient entrance skin dose. Results: In general, correlation between fluoroscopy time and ESD was not statistically significant (P =0.612). For all procedures, there was good overall correlation between DAP and ESD (r=0.809, P<0.001), and between CD and ESD (r=0.832, P<0.001). Dose index was significantly different for different procedures (F=8.214,P<0.001), but between CAG and HAIC, among SBAE, HACE, IIAE, it did not differ significantly in this regard (P>0.05). Within each individual procedure type, the rangeof values for the dose index varied from 2.2-fold to 3.1-fold between maximum and minmum. Conclusion: Fluoroscopy time is a poor predictor of risk because it does not correlate with ESD. CD and DAP are not good analogues of ESD because of weak correlations for some procedures and because of wide variations in the dose index for all procedures. Partâ…¢Study of Patient Effective Dose and Associated Radiogenic Risks from Four Interventional Radiology Procedures Objectives: To provide data for the accurate determination of patient effective dose (ED), gonadal dose from four interventional radiology procedures(CAG, SBAE, HACE, and IIAE) and to accurately estimate the radiation risk levels of following such procedures. Methods: An tissue-equivalent anthropomorphic phantom appropriately loaded with thermoluminescent dosimeters (TLDs) was used to obtain organ dose, surface dose and effective dose values from CAG, SBAE, HACE, and IIAE. DAP were monitored in 246 patients undergoing following such procedures. Conversion coefficients from DAP to effective dose were used to calculate patient effective dose, surface dose to organ dose conversion coefficients were used to calculate patient organ dose. Results: The effective dose from an average CAG procedure was 13.83 and 14.04mSv and the gonadal dose was 0.02 and 0.05 mGy for male and female patients, respectively. The average radiogenic risks for fatal cancer and genetic defects were 697 and 0.5 per million of patients treated, respectively. The effective dose from an averageSBAE procedure was 15.00 and 15.59 mSv and the gonadal dose was 0.04 and 0.17 mGy for male and female patients, respectively. The average radiogenic risks for fatal cancer and genetic defects were 765 and 1.4 per million of patients treated, respectively. The effective dose from an average HACE procedure was 34.27 and 34.85 mSv and the gonadal dose was 0.20 and 1.01 mGy for male and female patients, respectively. The average radiogenic risks for fatal cancer and genetic defects were 1728 and 7.9 per million of patients treated, respectively. The effective dose from an average IIAE procedure was 41.21 and 64.71 mSv and the gonadal dose was 12.89 and 35.75 mGy for male and female patients, respectively. The average radiogenic risks for fatal cancer and genetic defects were 2648 and 316 per million of patients treated, respectively. Conclusions: Patient dose and radiogenic risks associated with average following such procedures are tolerable, but it highly exceed radiation risk from medical X-ray examinations.For young patients with complex procedure requiring extended fluoroscopy, radiogenic risks may be considerable. Efforts should be made toward minimization of patient exposure from procedures.
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