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Proceedings Paper

Estimation of breast dose saving potential using a breast positioning technique for organ-based tube current modulated CT
Author(s): Wanyi Fu; Xiaoyu Tian; Gregory Sturgeon; Greeshma Agasthya; William Paul Segars; Mitchell M. Goodsitt; Ella A. Kazerooni; Ehsan Samei
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Paper Abstract

In thoracic CT, organ-based tube current modulation (OTCM) reduces breast dose by lowering the tube current in the 120° anterior dose reduction zone of patients. However, in practice the breasts usually expand to an angle larger than the dose reduction zone. This work aims to simulate a breast positioning technique (BPT) to constrain the breast tissue to within the dose reduction zone for OTCM and to evaluate the corresponding potential reduction in breast dose. Thirteen female anthropomorphic computational phantoms were studied (age range: 27-65 y.o., weight range: 52-105.8 kg). Each phantom was modeled in the supine position with and without application of the BPT. Attenuation-based tube current (ATCM, reference mA) was generated by a ray-tracing program, taking into account the patient attenuation change in the longitudinal and angular plane (CAREDose4D, Siemens Healthcare). OTCM was generated by reducing the mA to 20% between ± 60° anterior of the patient and increasing the mA in the remaining projections correspondingly (X-CARE, Siemens Healthcare) to maintain the mean tube current. Breast tissue dose was estimated using a validated Monte Carlo program for a commercial scanner (SOMATOM Definition Flash, Siemens Healthcare). Compared to standard tube current modulation, breast dose was significantly reduced using OTCM by 19.8±4.7%. With the BPT, breast dose was reduced by an additional 20.4±6.5% to 37.1±6.9%, using the same CTDIvol. BPT was more effective for phantoms simulating women with larger breasts with the average breast dose reduction of 30.2%, 39.2%, and 49.2% from OTCMBP to ATCM, using the same CTDIvol for phantoms with 0.5, 1.5, and 2.5 kg breasts, respectively. This study shows that a specially designed BPT improves the effectiveness of OTCM.

Paper Details

Date Published: 3 May 2016
PDF: 8 pages
Proc. SPIE 9783, Medical Imaging 2016: Physics of Medical Imaging, 97833C (3 May 2016); doi: 10.1117/12.2217239
Show Author Affiliations
Wanyi Fu, Duke Univ. (United States)
Xiaoyu Tian, Duke Univ. (United States)
Gregory Sturgeon, Duke Univ. (United States)
Greeshma Agasthya, Duke Univ. (United States)
William Paul Segars, Duke Univ. (United States)
Mitchell M. Goodsitt, Univ. of Michigan (United States)
Ella A. Kazerooni, Univ. of Michigan (United States)
Ehsan Samei, Duke Univ. (United States)

Published in SPIE Proceedings Vol. 9783:
Medical Imaging 2016: Physics of Medical Imaging
Despina Kontos; Thomas G. Flohr, Editor(s)

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