Estimating the Patient-specific Dose to the Thyroid and Breasts and Overall Risk in Chest CT When Using Organ-based Tube Current Modulation.
Caro FranckPeter SmeetsLore LapeireEric AchtenKlaus BacherPublished in: Radiology (2018)
Purpose To assess the potential dose reduction to the thyroid and breasts in chest computed tomography (CT) with organ-based tube current modulation (OBTCM). Materials and Methods In this retrospective study (from January 2015 to December 2016), the location of the breasts with respect to the reduced tube current zone was determined. With Monte Carlo simulations, patient-specific dose distributions of chest CT scans were calculated for 50 female patients (mean age, 53.7 years ± 17.5; range, 20-80 years). The potential dose reduction with OBTCM was assessed. In addition, simulations of clinical OBTCM scans were made for 17 of the 50 female patients (mean age, 43.8 years ± 17.1; range, 20-69 years). Posterior organs in the field of view were analyzed and lifetime attributable risk (LAR) of cancer incidence and mortality was estimated. Image quality between standard CT and OBTCM scans was compared. Results No women had all breast tissue within the reduced tube current zone. Dose reductions of 18% in the thyroid and 9% in the breasts were observed, whereas the doses in lung, liver, and kidney were 17%, 11%, and 26% higher. Overall, the LAR for cancer incidence was not significantly different between conventional and OBTCM scanning (P = .06). Image quality improved with OBTCM (P < .002). Conclusion The potential benefit of OBTCM to the female breast in chest CT is overestimated because of a limited reduced tube current zone; despite a 9% dose reduction to the female breast, posterior organs will absorb up to 26% more radiation, resulting in no reduction in radiation-induced malignancies. © RSNA, 2018.
Keyphrases
- image quality
- computed tomography
- dual energy
- positron emission tomography
- contrast enhanced
- radiation induced
- end stage renal disease
- monte carlo
- ejection fraction
- magnetic resonance imaging
- chronic kidney disease
- newly diagnosed
- squamous cell carcinoma
- risk factors
- prognostic factors
- papillary thyroid
- peritoneal dialysis
- magnetic resonance
- radiation therapy
- type diabetes
- molecular dynamics
- high resolution
- risk assessment
- pregnant women
- human health
- mass spectrometry
- cardiovascular disease
- pregnancy outcomes