Spatial Recognition: A Temporal Tale of Multiple Window Spatial Registration.

Purpose: The performance ability of position logic circuitry of gamma-camera to superimpose the X-Y gains obtained from different pulse height analyzers is multiple window spatial registration (MWSR). This study was conducted to evaluate the feasibility of dual-tracer method using ^99mTc and ¹³¹I to assess MWSR.

Materials and methods: The procedure was carried out on a dual-head gamma-camera with rectangular NaI (Tl) crystal using a point source containing ^99mTc pertechnetate and ¹³¹I-NaI. Pixel coordinates, full width at half-maximum of point spread function at 364 keV and 140 keV, and pixels with maximum count of images for dual detectors were analyzed and compared.

Results: The experiment demonstrated an excellent correlation between the X and Y coordinates identified on 364 keV and 140 keV images (Spearman's coefficient of rank correlation: 0.9, P < 0.0001). Intraclass correlation of studies performed on two separate occasions showed a good correlation (k = 0.87) demonstrating the reproducibility of the procedure.

Conclusion: Dual-tracer method for evaluation of MWSR is a reproducible, accurate, and logical alternative to the routine National Electrical Manufacturers Association procedure.