Ga-67 planar imaging with a low-energy collimator and scatter correction using the triple energy window method

To improve the spatial resolution and contrast of Ga-67 planar imaging, we used a low-energy collimator and two lower-energy windows with a triple-ene rgy-window (TEW) scatter compensation method. The spatial resolution is bet ter than with a medium-energy collimator, and the TEW method can correct fo r scattered photons and reduce the background counts. In a phantom study an d a clinical study involving 44 patients, the images obtained by the propos ed method were compared with the images obtained with a medium-energy colli mator and three energy windows without scatter compensation (the convention al method). The spatial resolution and the counts were measured. Two nuclea r medicine physicians interpreted the images and clinical usefulness was ev aluated. The spatial resolution and contrast were improved by our proposed method. It enabled the detection of lesions in five locations in the clinic al study. The counts were reduced but misreadings were not seen. We conclud e that our proposed method shows a clinical advantage over the conventional method. It can be used easily and quickly with commercially available equi pment and is useful in clinical practice. ((C) 1999 Lippincott Williams & W ilkins).