TITLE:
Image Quality Assessment Using NEMA Standards for Lu-177 Radionuclide
AUTHORS:
Olivia Adu-Poku, Bright Kwakye-Awuah, Eric Kotei Addison, Stephen Inkoom
KEYWORDS:
Lutetium-177, Activity Concentration, Dose Calibrator, SPECT/CT
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.11 No.3,
July
4,
2022
ABSTRACT: A lutetium 177 (177Lu)
radiopharmaceutical has been used as a theragnostic agent in molecular radiotherapies. This study aimed to
produce images simulating those obtained in a total body imaging study with hot
lesions to assess and investigate the image quality of the Hawkeye SPECT/CT
images from Lu-177. The NEMA image quality phantom (PTW) with spheres (inner
diameters of 10, 13, 17, 22, 28 and 37 mm) and lung insert was used. The measured volume in the background of the current phantom setting was
9482 mL. The five smaller spheres were filled with an activity concentration of 0.461 MBq/mL and the biggest
sphere was filled with water. The phantom was placed on the couch and scanned at four hot
sphere-to-background concentrations, which are no background, 16:1, 8:1 and 4:1. The images
obtained from the scans were imported onto the OXIRIS image analysis tool.
Regions of interest (ROIs) were drawn on each sphere of the reconstructed SPECT
image. Image contrast and background
variability ratios for hot spheres were used as measures of image quality. In
addition, the accuracy of corrections were determined from the uniform
background and cold lung insert regions. The 37 mm cold sphere had the highest
percent contrast, whiles the 10 mm hot sphere had the least for the
various hot sphere to background ratios. The background variability for each
hot sphere was also determined. The average lung residual error was calculated
to be 23.13% for the 16:1 and 22.57% for both the 8:1 and 4:1 hot sphere to
background ratio. The results show that the scanner has very good overall
performance.