SPECT images shown here were acquired using a dedicated brain-imaging instrument equipped with a stationary annular NaI crystal and a rotating collimator system [1,2]. The measured system resolution in air, using capillary line sources, is 8.2 mm at the center and 7.3 mm at 9 cm from the center for Tc- 99m . Images are acquired 20 minutes after intravenous injection of 20 +/- 1.0 mCi of Tc-99m-HMPAO (Ceretec, Amersham Ltd., Amersham, UK), with patients supine, at rest, with eyes open, in a darkened room; total acquisition time is 20 minutes. Sixty-four slices were reconstructed in a 128 x 128 matrix with each pixel measuring 1.67 x 1.67 mm., and attenuation corrected. Our SPECT images are registered with MR images, using Superpose, and are usually displayed in the MR coordinate system.
1. Holman BL, Carvalho PA, et al. Brain perfusion SPECT using an annular single crystal camera: initial clinical experience. J Nucl Med. 1990; 31: p. 1456-1461.
2. Genna S and Smith AP. The development of ASPECT, an annular single crystal brain camera for high efficiency SPECT. IEEE Trans Nucl Sci. 1988; NS-35: p. 654-658.