Gamma | Comprehension and appropriate use of a flood table on a gamma…
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작성자 : 서울대 핵의학과 작성일2017-02-01 조회3,156회관련링크
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Jae Il Kim, 1 Jeom Jin Im, 1 Seong Wook Cho, 2 Jin Eui Kim, 1 and Hyun Joo Kim 1
Departments of Nuclear Medicine, Seoul National University, Seoul, Korea
Background and Purpose: Uniformity is the one of the important quality control features with respect to gamma cameras. To maintain adequate uniformity, we must acquire suitable flood table (= flood map) data because the flood table effects energy, and the type or dose of input radiation. Therefore, in this study we evaluated the difference in uniformity when uniformity does not match between the type of input radiation and the flood table data or collimator type.
Subjects and Methods: For input radiation, we prepared 10 mCi of 57Co, 99mTc, and 201Tl.
Using SKYLight (Philips) and Infinia gamma cameras (GE), we acquired nine uniformity data that were corrected by technetium, cobalt flood table and did not corrected image for the three sources. Additionally, we acquired two uniformity images with a collimator that were corrected by intrinsic and extrinsic flood tables. Using this data, we evaluated and compared the uniformity values.
Results: In the case of the SKYLight gamma camera, the uniformities of the images that matched between the input radiation and flood table with respect to 99mTc and 57Co were better than the unmatched uniformity, as shown in Table 1. However, because there was no thallium flood table, the uniformities of images at Tl were significantly incorrect. The uniformities of the Infinia gamma camera had the same pattern as the SKYLight gamma camera. Moreover, the uniformity of the 99mTc image acquired with a collimator and corrected by an extrinsic flood table was better than the intrinsic flood table.
Conclusion: Correcting an image by a suitable flood table can help achieve better uniformity for a gamma camera. Therefore, we have to acquire images with suitable uniformity correction, and update the flood table periodically. Whenever we acquire a nuclear medicine image, we always have to check the appropriate flood table according to the acquired condition.