Bias and precision of SPECT-based 177Lu activity-concentration estimation using a ring-configured solid-state versus a dual-headed anger system

Bibliographic Details
Title: Bias and precision of SPECT-based 177Lu activity-concentration estimation using a ring-configured solid-state versus a dual-headed anger system
Authors: Anna Stenvall, Irma Ceric Andelius, Elias Nilsson, Albin Lindvall, Erik Larsson, Johan Gustafsson
Source: EJNMMI Physics, Vol 11, Iss 1, Pp 1-21 (2024)
Publisher Information: SpringerOpen, 2024.
Publication Year: 2024
Collection: LCC:Medical physics. Medical radiology. Nuclear medicine
Subject Terms: Quantitative SPECT, Lutetium-177, Ring-configured SPECT, Cadmium-zinc-telluride, Medical physics. Medical radiology. Nuclear medicine, R895-920
More Details: Abstract Background The aim was to compare bias and precision for 177Lu-SPECT activity-concentration estimation using a dual-headed Anger SPECT system and a ring-configured CZT SPECT system. This was investigated for imaging at 208 keV and 113 keV, respectively. Methods Phantom experiments were performed on a GE Discovery 670 system with 5/8’’ NaI(Tl) crystal (dual-headed Anger system) and a GE StarGuide (ring-configured CZT system). Six spheres (1.2 mL to 113 mL) in a NEMA PET body phantom were filled with 99mTc and 177Lu, separately. Mean relative errors and coefficients of variation (CV) in estimated sphere activity concentration were studied over six timeframes of 10 min each for the two systems. For 177Lu, similar acquisitions were also performed for an anthropomorphic phantom with two spheres (10 mL and 25 mL) in a liver with non-radioactive background and a sphere-to-background ratio of 15:1. Tomographic reconstruction was performed using OS-EM with 10 subsets with compensation for attenuation, scatter, and distance-dependent spatial resolution. For the Anger system, up to 40 iterations were used and for the ring-configured CZT system up to 30 iterations were used. Results The two systems showed similar mean relative errors and CVs for 177Lu when using an energy window around 208 keV, while the ring-configured system demonstrated a lower bias for a similar CV compared to the Anger system for 99mTc and for 177Lu when using an energy window around 113 keV. However, total activity in the phantom tended to be overestimated in both systems for these cases. Conclusions The ring-configured CZT system is a viable alternative to the dual-headed Anger system equipped with medium-energy collimators for 177Lu-SPECT and shows a potential advantage for activity-concentration estimation when operated at 113 keV. However, further consideration of the preservation of total activity is warranted.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2197-7364
Relation: https://doaj.org/toc/2197-7364
DOI: 10.1186/s40658-024-00693-5
Access URL: https://doaj.org/article/c27646b4f0bc454ab4ec281054570693
Accession Number: edsdoj.27646b4f0bc454ab4ec281054570693
Database: Directory of Open Access Journals
More Details
ISSN:21977364
DOI:10.1186/s40658-024-00693-5
Published in:EJNMMI Physics
Language:English