OBJECTIVE: To investigate the usefulness of modifying scanning parameters based on the size-specific dose estimate (SSDE) for a breast-dose reduction for chest CT. MATERIALS AND METHODS: We scanned 26 women with a fixed volume CT dose index (CTDIvol) (15 mGy) and another 26 with a fixed SSDE (15 mGy) protocol (protocol 1 and 2, respectively). In protocol 2, tube current was calculated based on the patient habitus obtained on scout images. We compared the mean breast dose and the inter-patient breast dose variability and performed linear regression analysis of the breast dose and the body mass index (BMI) of the two protocols. RESULTS: The mean breast dose was about 35 % lower under protocol 2 than protocol 1 (10.9 mGy vs. 16.8 mGy, p < 0.01). The inter-patient breast dose variability was significantly lower under protocol 2 than 1 (1.2 mGy vs. 2.5 mGy, p < 0.01). We observed a moderate negative correlation between the breast dose and the BMI under protocol 1 (r = 0.43, p < 0.01); there was no significant correlation (r = 0.06, p = 0.35) under protocol 2. CONCLUSION: The SSDE-based protocol achieved a reduction in breast dose and in inter-patient breast dose variability. KEY POINTS: • CT scan parameters can be modified based on the pre-scan SSDE. • The pre-scan SSDE is useful for a breast dose reduction. • The fixed SSDE protocol reduced individual variations in the breast dose.
RCT Entities:
OBJECTIVE: To investigate the usefulness of modifying scanning parameters based on the size-specific dose estimate (SSDE) for a breast-dose reduction for chest CT. MATERIALS AND METHODS: We scanned 26 women with a fixed volume CT dose index (CTDIvol) (15 mGy) and another 26 with a fixed SSDE (15 mGy) protocol (protocol 1 and 2, respectively). In protocol 2, tube current was calculated based on the patient habitus obtained on scout images. We compared the mean breast dose and the inter-patient breast dose variability and performed linear regression analysis of the breast dose and the body mass index (BMI) of the two protocols. RESULTS: The mean breast dose was about 35 % lower under protocol 2 than protocol 1 (10.9 mGy vs. 16.8 mGy, p < 0.01). The inter-patient breast dose variability was significantly lower under protocol 2 than 1 (1.2 mGy vs. 2.5 mGy, p < 0.01). We observed a moderate negative correlation between the breast dose and the BMI under protocol 1 (r = 0.43, p < 0.01); there was no significant correlation (r = 0.06, p = 0.35) under protocol 2. CONCLUSION: The SSDE-based protocol achieved a reduction in breast dose and in inter-patient breast dose variability. KEY POINTS: • CT scan parameters can be modified based on the pre-scan SSDE. • The pre-scan SSDE is useful for a breast dose reduction. • The fixed SSDE protocol reduced individual variations in the breast dose.
Entities:
Keywords:
Breast radiation dose; CTDIvol; Chest CT; MOSFET; SSDE
Authors: R E Shore; L H Hempelmann; E Kowaluk; P S Mansur; B S Pasternack; R E Albert; G E Haughie Journal: J Natl Cancer Inst Date: 1977-09 Impact factor: 13.506
Authors: Erin Angel; Nazanin Yaghmai; Cecilia Matilda Jude; John J Demarco; Christopher H Cagnon; Jonathan G Goldin; Andrew N Primak; Donna M Stevens; Dianna D Cody; Cynthia H McCollough; Michael F McNitt-Gray Journal: Phys Med Biol Date: 2009-01-06 Impact factor: 3.609