TY - JOUR
T1 - A Projection-Domain Low-Count Quantitative SPECT Method for -Particle-Emitting Radiopharmaceutical Therapy
AU - Li, Zekun
AU - Benabdallah, Nadia
AU - Abou, Diane S.
AU - Baumann, Brian C.
AU - Dehdashti, Farrokh
AU - Ballard, David H.
AU - Liu, Jonathan
AU - Jammalamadaka, Uday
AU - Laforest, Richard L.
AU - Wahl, Richard L.
AU - Thorek, Daniel L.J.
AU - Jha, Abhinav K.
N1 - Publisher Copyright:
© 2017 IEEE.
PY - 2023/1/1
Y1 - 2023/1/1
N2 - Single-photon emission-computed tomography (SPECT) provides a mechanism to estimate regional isotope uptake in lesions and at-risk organs after administration of α -particle-emitting radiopharmaceutical therapies ( α -RPTs). However, this estimation task is challenging due to the complex emission spectra, the very low number of detected counts ( ∼ 20 times lower than in conventional SPECT), the impact of stray-radiation-related noise at these low counts, and the multiple image-degrading processes in SPECT. The conventional reconstruction-based quantification methods are observed to be erroneous for α -RPT SPECT. To address these challenges, we developed a low-count quantitative SPECT (LC-QSPECT) method that directly estimates the regional activity uptake from the projection data (obviating the reconstruction step), compensates for stray-radiation-related noise, and accounts for the radioisotope and SPECT physics, including the isotope spectra, scatter, attenuation, and collimator-detector response, using a Monte Carlo-based approach. The method was validated in the context of 3-D SPECT with 223 Ra , a commonly used radionuclide for α -RPT. Validation was performed using both realistic simulation studies, including a virtual clinical trial, and synthetic and 3-D-printed anthropomorphic physical-phantom studies. Across all studies, the LC-QSPECT method yielded reliable regional-uptake estimates and outperformed the conventional ordered subset expectation-maximization (OSEM)-based reconstruction and geometric transfer matrix (GTM)-based post-reconstruction partial-volume compensation methods. Furthermore, the method yielded reliable uptake across different lesion sizes, contrasts, and different levels of intralesion heterogeneity. Additionally, the variance of the estimated uptake approached the Cramér-Rao bound-defined theoretical limit. In conclusion, the proposed LC-QSPECT method demonstrated the ability to perform reliable quantification for α -RPT SPECT.
AB - Single-photon emission-computed tomography (SPECT) provides a mechanism to estimate regional isotope uptake in lesions and at-risk organs after administration of α -particle-emitting radiopharmaceutical therapies ( α -RPTs). However, this estimation task is challenging due to the complex emission spectra, the very low number of detected counts ( ∼ 20 times lower than in conventional SPECT), the impact of stray-radiation-related noise at these low counts, and the multiple image-degrading processes in SPECT. The conventional reconstruction-based quantification methods are observed to be erroneous for α -RPT SPECT. To address these challenges, we developed a low-count quantitative SPECT (LC-QSPECT) method that directly estimates the regional activity uptake from the projection data (obviating the reconstruction step), compensates for stray-radiation-related noise, and accounts for the radioisotope and SPECT physics, including the isotope spectra, scatter, attenuation, and collimator-detector response, using a Monte Carlo-based approach. The method was validated in the context of 3-D SPECT with 223 Ra , a commonly used radionuclide for α -RPT. Validation was performed using both realistic simulation studies, including a virtual clinical trial, and synthetic and 3-D-printed anthropomorphic physical-phantom studies. Across all studies, the LC-QSPECT method yielded reliable regional-uptake estimates and outperformed the conventional ordered subset expectation-maximization (OSEM)-based reconstruction and geometric transfer matrix (GTM)-based post-reconstruction partial-volume compensation methods. Furthermore, the method yielded reliable uptake across different lesion sizes, contrasts, and different levels of intralesion heterogeneity. Additionally, the variance of the estimated uptake approached the Cramér-Rao bound-defined theoretical limit. In conclusion, the proposed LC-QSPECT method demonstrated the ability to perform reliable quantification for α -RPT SPECT.
KW - Radium-223
KW - low counts
KW - quantitative single-photon emission-computed tomography (SPECT)
KW - regional quantification
KW - α-particle therapies
UR - http://www.scopus.com/inward/record.url?scp=85130802710&partnerID=8YFLogxK
U2 - 10.1109/TRPMS.2022.3175435
DO - 10.1109/TRPMS.2022.3175435
M3 - Article
AN - SCOPUS:85130802710
SN - 2469-7311
VL - 7
SP - 62
EP - 74
JO - IEEE Transactions on Radiation and Plasma Medical Sciences
JF - IEEE Transactions on Radiation and Plasma Medical Sciences
IS - 1
ER -