TITLE:
Efforts to Improve the Images from 67Ga Whole-Body Scintigraphy
AUTHORS:
Kyoko Saito, Yasuyuki Takahashi, Naomi Ogano, Hirotaka Shimada, Takao Kanzaki, Hiroki Okada, Kei Yokota, Kaori Hatano, Yuki Yoshida, Tetsuya Higuchi
KEYWORDS:
67Ga Imaging, LME Collimator, MDW Scatter Correction
JOURNAL NAME:
World Journal of Nuclear Science and Technology,
Vol.5 No.1,
December
22,
2014
ABSTRACT: The
acquisition method for planar 67Ga imaging has hardly changed for 30
years. In this study, in order to improve image quality and diagnostic accuracy,
we take steps to optimize the acquisition method, and to choose a scatter
correction. First, we acquired individual images from the 93 keV, 185 keV, and
300 keV photopeak; then the images were added together and compared to the
individual images. Second, we compared results from a low-medium-energy (LME)
collimator with those from a conventional medium-energy (ME) collimator. Also,
we examined whether to combine the data from all three of the usual window
locations (set about 93 keV, 185 keV, and 300 keV) or to use the data from only
two. Third, we compared results from a conventional photopeak ± 10％ window with those from a
photopeak ± 9 keV window. Fourth, for scatter correction we compared results
using the triple energy window (TEW) method with those using the multi-photopeak
dual window (MDW) method. The phantoms studied were cold rods in a uniform
background, and hot spheres within a cylinder containing uniformly radioactive
water. The clinical study involved 22 patients with lung lesions. By the
comparison by the contrast ratio in cold rods phantom, 15.6% is improved in LME
(2 peaks) than ME (3 peaks), and 3.2% is improved in photopeak ± 9 keV than
photopeak ± 10%, 10.2% is improved in TEW than MDW. However, the TEW scatter
correction method recognized unstable to the contrast ratio in a clinical
study. In addition, a body outline might disappear.