Konstantinos Perisinakis PhD, Presenter: Nothing to Disclose

Ioannis Seimenis, Abstract Co-Author: Nothing to Disclose

Antonis Tzedakis MS, Abstract Co-Author: Nothing to Disclose

Antonis Papadakis PhD, Abstract Co-Author: Nothing to Disclose

John Emmanuel Damilakis MD, Abstract Co-Author: Nothing to Disclose

To estimate the radiation burden and associated risks for radiation-induced cancer in patients subjected to typical triple-rule-out CT angiography (TRO-CTA) on 256-slice CT scanners.

A dedicated Monte Carlo CT dosimetry software package was used to simulate typical prospectively and retrospectively ECG-gated TRO-CTA scans with a 256-slice CT scanner on 28 patient specific voxelized phantoms. Dose-images depicting the dose deposition on the exposed region were generated and organ doses for all primarily exposed radiosensitive organs were derived and correlated to patient body habitus. Absorbed doses to lung, breast, esophagus, liver, stomach and heart were determined for 15 male and 13 female patients subjected to TRO-CTA. Risks of radiation-induced cancer were estimated using risk factors provided by Biological Effects of Ionizing Radiation VII phase 2 report and a) patient effective doses derived by dose-length-product (DLP) and b) absorbed doses to radiosensitive organs. 

Organ doses from TRO-CTA were found to depend significantly on patient body size (p<0.0001). The risk of radiogenic cancer following TRO-CTA decreases steeply with age at exposure, whilst lung cancer constitutes the more probable detriment for both genders. The mean theoretical radiogenic risks for cancer induction were estimated to be 45 x 10-5and 126 x 10-5 for female patients undergoing prospectively and retrospectively ECG-gated TRO-CTA, respectively. The corresponding values for males were 12 x 10-5 and 51 x 10-5.

Prospectively ECG-gated TRO-CTA with 256-slice CT scanners is associated with a total radiation-induced cancer risk of 1:2200 in female and 1:7800 in male patients examined. The use of data regarding absorbed dose to radiosensitive organs should be preferred against DLP-derived patient effective dose for the assessment of radiogenic risks from CT exposures.

Current estimates of the risk for radiation-induced cancer may allow reliable risk-benefit assessment for patients referred for TRO-CTA on 256-slice CT scanners.  

Perisinakis, K, Seimenis, I, Tzedakis, A, Papadakis, A, Damilakis, J, Triple-Rule-Out CT Angiography with 256-Slice CT Scanners: What Is the Level of Patient Radiation Burden and Associated Risk for Radiation-induced Cancer?.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9009901.html