Technical aspects of bone scintigraphy.

Optimal bone scintigraphy is obtained by using a current generation gamma camera with a high-resolution collimator, minimizing the patient-to-collimator distance, using scatter reduction techniques where possible, and obtaining a 500,000 to 1 million count image for 40-cm field of view camera. Hard copy images from an analog or digital formatter should be optimized to display all intensities either on the same images or, when necessary, to display the low count information on one image and the high count information on another. Additional images using different collimators, such as converging or pinhole collimators, and oblique and lateral views should be obtained when necessary to demonstrate or define the pathologic area. To optimize SPECT imaging, the following parameters should be used: a high-resolution collimator, a 128 x 128 acquisition matrix, and minimum separation between the patient and the collimator, which may require the use of an elliptic orbit. Between 64 and 128 views should be obtained, and depending on preference, the planar data should be prefiltered with a Butterworth, order 8-12 and a cutoff at 0.5 Nyquist. The data should then be reconstructed using a simple ramp filter. This method provides a good technique when one is first beginning to perform bone SPECT. Attenuation correction is not generally beneficial for SPECT bone studies, although sometimes weighted backprojection may improve image contrast and resolution. Finally, the use of volume rendering may help clarify the location of suspect lesions.