The role of single photon emission computed tomography in bone imaging

Single photon emission computed tomography (SPECT) of the bone is the secon d most frequently performed SPECT examination in routine nuclear medicine p ractice, with cardiac SPECT being the most frequent. Compared with planar s cintigraphy, SPECT increases image contrast and improves lesion detection a nd localization. Studies have documented the unique diagnostic information provided by SPECT, particularly for avascular necrosis of the femoral head, in patients with back pain, for the differential diagnosis between maligna nt and benign spinal lesions, in the detection of metastatic cancer in the spine, for the diagnosis of temporomandibular joint internal derangement, a nd for the evaluation of acute and chronic knee pain. Although less rigorou sly documented, SPECT is being increasingly used in all types of situations that demand more precise anatomic localization of abnormal tracer uptake. The effectiveness of bone SPECT increases with the selection of the proper collimator, which allows one to acquire adequate counts and minimize the pa tient-to-detector distance, Low-energy, ultrahigh-resolution or high-resolu tion collimation is preferred over all-purpose collimators. Multihead gamma cameras can increase the counts obtained or shorten acquisition time, maki ng SPECT acquisitions more practical in busy departments and also increasin g image quality compared with single-head cameras. Iterative reconstruction , with the use of ordered subsets estimation maximization, provides better quality images than classical filtered back projection algorithms. Three-di mensional image analysis often aids lesion localization. Copyright a 2001 by W.B. Saunders Company.