In:
Medical Physics, Wiley, Vol. 44, No. 2 ( 2017-02), p. 665-678
Abstract:
This study aimed to investigate the breast dose reduction potential of a breast‐positioning ( BP ) technique for thoracic CT examinations with organ‐based tube current modulation ( OTCM ). Methods This study included 13 female anthropomorphic computational phantoms ( XCAT , age range: 27–65 y.o., weight range: 52–105.8 kg). Each phantom was modified to simulate three breast sizes in standard supine geometry. The modeled breasts were then morphed to emulate BP that constrained the majority of the breast tissue inside the 120° anterior tube current ( mA ) reduction zone. The OTCM mA value was modeled using a ray‐tracing program, which reduced the mA to 20% in the anterior region with a corresponding increase to the posterior region. The organ doses were estimated by a validated Monte Carlo program for a typical clinical CT system ( SOMATOM Definition Flash, Siemens Healthcare). The simulated organ doses and organ doses normalized by CTDI vol were used to compare three CT protocols: attenuation‐based tube current modulation ( ATCM ), OTCM , and OTCM with BP (OTCM BP ). Results On average, compared to ATCM , OTCM reduced breast dose by 19.3 ± 4.5%, whereas OTCM BP reduced breast dose by 38.6 ± 8.1% (an additional 23.8 ± 9.4%). The dose saving of OTCM BP was more significant for larger breasts (on average 33, 38, and 44% reduction for 0.5, 1, and 2 kg breasts, respectively). Compared to ATCM , OTCM BP also reduced thymus and heart dose by 15.1 ± 7.4% and 15.9 ± 6.2% respectively. Conclusions In thoracic CT examinations, OTCM with a breast‐positioning technique can markedly reduce unnecessary exposure to radiosensitive organs in anterior chest wall, specifically breast tissue. The breast dose reduction is more notable for women with larger breasts.
Type of Medium:
Online Resource
ISSN:
0094-2405
,
2473-4209
DOI:
10.1002/mp.2017.44.issue-2
Language:
English
Publisher:
Wiley
Publication Date:
2017
detail.hit.zdb_id:
1466421-5
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