Improved Quality of Pediatric 123I-MIBG Images with Medium-Energy Collimators

Journal of Nuclear Medicine Technology

Frederic H. Fahey¹  Erin R. Snay¹  S. Ted Treves¹ 

[1] Division of Nuclear Medicine and Molecular Imaging, Children's Hospital Boston, Boston, Massachusetts Division of Nuclear Medicine and Molecular Imaging, Children's Hospital Boston, Boston, Massachusetts Division of Nuclear Medicine and Molecular Imaging, Children's Hospital Boston, Boston, Massachusetts

关键词: SPECT;    ¹²³I-MIBG;    pediatric;    planar scintigraphy;   

DOI  :  10.2967/jnmt.110.080309

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Our objective was to optimize the quality of 123I-metaiodobenzylguanidine (MIBG) scans by using a medium-energy collimator to reduce high-energy-photon septal penetration. Methods: In addition to the 159-keV γ-ray, 123I has a small abundance of energies above 400 keV that can compromise the image quality of MIBG studies because of septal penetration. Using a low-energy ultrahigh-resolution collimator (LEUHR), a low-energy high-resolution collimator (LEHR), and a medium-energy collimator, we obtained and compared SPECT and planar images of a SPECT phantom filled with 123I. These studies were acquired at a count level comparable to clinical MIBG images, 24,000 counts per view for SPECT and 300,000 counts for planar imaging. Also, we evaluated the sensitivity of the 3 collimators at 0 and 10 cm using the National Electrical Manufacturers Association protocol. Results: The image quality for both SPECT and planar 123I images using the medium-energy collimator was determined to be substantially better than that using the LEUHR or LEHR collimator. The septa of the medium-energy collimator are thicker than those of the low-energy collimators (1.14 vs. 0.13–0.16 mm), leading to a significant reduction in septal penetration of the high-energy γ-rays and a marked improvement in image quality. The sensitivity for the medium-energy collimator did not change with distance (8.00 cpm/kBq), as opposed to the LEUHR collimator (6.59 and 5.51 cpm/kBq for 0 and 10 cm, respectively) and the LEHR collimator (14.32 and 12.30 cpm/kBq for 0 and 10 cm, respectively). This variation in sensitivity for the LEUHR collimator is again due to the presence of high-energy photons. Conclusion: Use of a medium-energy collimator substantially improves the quality of both planar and SPECT 123I images. We recommend that a medium-energy collimator routinely be used for 123I-MIBG imaging.

【 授权许可】

Unknown