Fig. 2

Representative images of regions of interest (ROIs) placements for quantitative analysis. In the anterior (a) and posterior (b) view of the knee plane image, circular ROIs 15 mm in diameter were drawn on the medial femoral, lateral femoral, medial tibial, lateral tibial, and patella regions, and the same size of ROI was set on the right thigh soft tissue as a reference region. In the SPECT/CT images, volumes of interest (VOIs, red marked regions of c and d images) were manually drawn in the regions corresponding to the right lateral femoral region in CT (c: sagittal image, d: transaxial image). This drawn VOI was projected on the SPECT image (e sagittal image, f transaxial image) of the same area, and the VOI (red marked part of e and f image) was set