By decreasing the tube voltage, the amount of contrast material can be reduced without image quality degradation. In scans obtained with a low tube voltage, the radiation dose can be reduced as much as 56.8%, and higher contrast material enhancement can be achieved.

Results demonstrate the increased diagnostic confidence obtained with fused SPECT/CT images compared with separate sets of scintigraphic and CT images in differentiating malignant from benign bone lesions.

Purpose:To determine whether quantitative diffusionweighted imaging (DWI) is useful for characterizing poorly contrast-enhanced and T2-prolonged bone masses. Materials and Methods:We studied 20 bone masses that showed high signal intensity on T2-weighted images and poor enhancement on contrast-enhanced T1-weighted images. These included eight solitary bone cysts, five fibrous dysplasias, and seven chondrosarcomas. To analyze diffusion changes we calculated the apparent diffusion coefficient (ADC) for each lesion. Results:The ADC values of the two types of benign lesions and chondrosarcomas were not significantly different. However, the mean ADC value of solitary bone cysts (mean ϮSD, 2.57 Ϯ 0.13 ϫ 10 -3 mm 2 /second) was significantly higher than that of fibrous dysplasias and chondrosarcomas (2.0 Ϯ 0.21 ϫ 10 -3 mm 2 /second and 2.29 Ϯ 0.14 ϫ 10 -3 mm 2 /second, respectively, P Ͻ 0.05). None of the lesions with ADC values lower than 2.0 ϫ 10 -3 mm 2 /second were chondrosarcomas. Conclusion:Although there was some overlapping in the ADC values of chondrosarcomas, solitary bone cyst, and fibrous dysplasia, quantitative DWI may aid in the differential diagnosis of poorly contrast-enhanced and T2-prolonged bone masses.

• The 80-kVp CT protocol enabled reduction of contrast dose by 50 % • The 80-kVp CT protocol reduced the radiation dose by 25-33 % • There was no degradation in the image quality of the 80-kVp protocol.

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