Radiation dose and cancer risk estimates in 16-slice computed tomography coronary angiography (original) (raw)
Related papers
Temporal Trends in Radiation Dose Associated with Coronary Computed Tomography Angiography
Open Journal of Radiology, 2014
Background: In 2010, the International Atomic Energy Agency launched the "3A's campaign" as an effective tool for primary cancer prevention. In 2011, the American Association of Physicists in Medicine recommended the size specific dose estimate (SSDE). Objectives: To audit doses of Coronary CT Angiography (Coronary CTA) in tertiary care referral center. Methods: We reviewed 998 consecutive Coronary CTA (from 2007 to 2012). Doses (CTDIvol mGy), DLP (mGy*cm), effective dose (DLP*0.014, mSv) were on-line archived. SSDE was estimated retrospectively. Appropriateness score was evaluated for exams performed from the 2010. Results: Overall median dose per Coronary CTA was 49.7 mGy for CTDIvol, 55.5 mGy for SSDE, 994.96 mGy*cm for DLP, 13.9 mSv for effective dose. Median DLP decreased over time (and 497.88 mGy*cm in 2012, p < 0.0001). SSDE was proportional to the size dependent factor (SDF); in patients with SDF > 1 (88%) CTDIvol underestimated SSDE (48.49 vs 57.19 mGy), whilst in patients with SDF < 1 (12%) CTDIvol overestimated SSDE (56.46 vs 50.3 mGy). Scans were appropriate in 58%, uncertain in 24%, and inappropriate in 18% of cases. Doses were similar in appropriate, uncertain or inappropriate examinations and in excellent-to-good (81%) vs. sufficient-to-poor (19%) image quality exams. Conclusions: Coronary CTA reference doses can be very misleading. SSDE can allow individual technique optimization. The dose is similar in appropriate and inappropriate examinations, and unrelated to image quality. The rate of inappropriate examinations is still too high even after dissemination of guidelines. * Corresponding author. P. Marraccini et al.
Circulation, 2010
Background-Available data on the radiation burden from coronary computed tomography (CT) angiography (CCTA) are mostly limited to effective dose estimates. This study provides individualized estimates of doses and associated life attributable risks of radiation-induced cancer in a clinical patient population undergoing 256-slice CCTA. Methods and Results-Typical retrospectively and prospectively ECG-gated CCTA exposures in a 256-slice CT scanner were simulated on 52 patient-specific voxelized phantoms. Dose images depicting the dose deposition on the exposed region were generated, and normalized organ doses for all primarily irradiated radiosensitive organs were derived and correlated to patient body habitus. Lung, breast, and esophagus absorbed doses were then determined in 136 consecutive patients subjected to CCTA. Projected life attributable risks of radiation-induced cancer were estimated through the use of appropriate sex-, age-and organ-specific cancer risk factors and compared with corresponding nominal cancer risks. The total projected life attributable risk of radiogenic cancer after CCTA decreases steeply with age at exposure, and lung cancer constitutes the most probable detriment for both sexes. The relative risks of lung cancer associated with prospectively ECG-gated CCTA were 1.0032 and 1.0008 for women and men, respectively. The mean total projected life attributable risks were estimated to be 24.9Ϯ7.4 and 71.5Ϯ30.0 per 100 000 women undergoing prospectively and retrospectively ECG-gated CCTA, respectively. The corresponding values for men were 7.3Ϯ1.3 and 31.4Ϯ5.0 per 100 000 patients. Conclusions-The mean projected life attributable risks of radiation-induced cancer in a typical clinical patient cohort undergoing standard prospectively ECG-gated CCTA with a 256-slice scanner were found to inconsequentially increase the natural cancer incidence rates. (Circulation. 2010;122:2394-2402.
Journal of Medical Imaging and Radiation Oncology, 2012
The purpose of this paper is to perform a systematic review on radiation dose reduction in coronary computed tomography (CT) angiography that is done using different generations of multidetector CT (MDCT) scanners ranging from four-slice to 320-slice CTs, and have different dose-saving techniques. The method followed was to search for references on coronary CT angiography (CTA) that had been published in English between 1998 and February 2011. The effective radiation dose reported in each study based on different generations of MDCT scanners was analysed and compared between the types of scanners, gender, exposure factors and scanning protocols. Sixty-six studies were eligible for inclusion in this analysis. The mean effective dose (ED) for MDCT angiography with retrospective electrocardiogram (ECG) gating without use of any dose-saving protocol was 6.0 Ϯ 2.8, 10.4 Ϯ 4.90 and 11.8 Ϯ 5.9 mSv for four-slice, 16-slice and 64-slice CTs, respectively. More dosesaving strategies were applied in recent CT generations including prospective ECG-gating protocols, application of lower tube voltage and tube current modulation to achieve a noteworthy dose reduction. Prospective ECGgating protocol was increasingly used in 64, 125, 256 and 320 slices with corresponding ED of 4.1 Ϯ 1.7, 3.6 Ϯ 0.4, 3.0 Ϯ 1.9 and 7.6 Ϯ 1.6 mSv, respectively. Lower tube voltage and tube current modulation were widely applied in 64-slice CT and resulted in significant dose reduction (P < 0.05). This analysis has shown that dose-saving strategies can substantially reduce the radiation dose in CT coronary angiography. The fact that more and more clinicians are opting for dose-saving strategies in CT coronary angiography indicates an increased awareness of risks associated with high radiation doses among them.
Estimation of radiation dose and associated cancer risks from computed tomographic scans
2018
Absorbed dose of 100 patients during CT imaging procedure in a renowned hospital of Dhaka city were measured using Thermoluminescence (TL) chips. For dose measurement at the scanned region TL chips were sealed in a uniform manner with 10 rows and 5 columns between two polythene sheets. Fifty TL chips were used for each CT scan at the scanned region. These TL chips were readout using the Harshaw TLD Reader (model 3500) of Health Physics Division, Atomic Energy Center, BAEC, Dhaka. The patients were selected randomly based on three different CT types e.g. CT abdomen, CT chest and CT head. Applied voltage, applied current, exposure time, scanning length, dose length product (DLP), age and sex of the patient were recorded for each CT scan. The maximum value of absorbed dose was obtained 79.05 mSv for CT head scanning and the minimum value of it was obtained 1.27 mSv for CT abdomen scanning. The effective dose was calculated by multiplying DLP value obtained from the dose report with the conversion coefficient provided by European Guidelines for multi-slice computed tomography (MSCT). The maximum and minimum value of effective dose was obtained 45.93 mSv for CT abdomen and 1.24 mSv for CT head scanning respectively. The lifetime attributable risk (LAR) of cancer was also estimated using web based calculator X-rayrisk.com. It was observed that the LAR of cancer increases with the decrease of patient age and the increase of the effective dose. Therefore, pediatric patients are in higher radiation risk than adult patients. So it is very important in radiology departments to monitor and control the dose of the patients during CT imaging procedures and the dose should always be as low as reasonably achievable.
Reduction in Radiation Exposure in Cardiovascular CT Imaging
European Heart Journal, 2018
Aims Advances of cardiac computed tomography angiography (CTA) have been developed for dose reduction, but their efficacy in clinical practice is largely unknown. This study was designed to evaluate radiation dose exposure and utilization of dose-saving strategies for contrast-enhanced cardiac CTA in daily practice.