Use of a ray-based reconstruction algorithm to accurately quantify preclinical microSPECT images.
This work aimed to measure the in vivo quantification errors obtained when ray-based iterative reconstruction is used in micro-single-photon emission computed tomography (SPECT). This was investigated with an extensive phantom-based evaluation and two typical in vivo studies using 99mTc and 111In, measured on a commercially available cadmium zinc telluride (CZT)-based small-animal scanner. Iterative reconstruction was implemented on the GPU using ray tracing, including (1) scatter correction, (2) computed tomography-based attenuation correction, (3) resolution recovery, and (4) edge-preserving smoothing. It was validated using a National Electrical Manufacturers Association (NEMA) phantom. The in vivo quantification error was determined for two radiotracers: [99mTc]DMSA in naive mice (n  =  10 kidneys) and [111In]octreotide in mice (n  =  6) inoculated with a xenograft neuroendocrine tumor (NCI-H727). The measured energy resolution is 5.3% for 140.51 keV (99mTc), 4.8% for 171.30 keV, and 3.3% for 245.39 keV (111In). For 99mTc, an uncorrected quantification error of 28 ± 3% is reduced to 8 ± 3%. For 111In, the error reduces from 26 ± 14% to 6 ± 22%. The in vivo error obtained with 99mTc-dimercaptosuccinic acid ([99mTc]DMSA) is reduced from 16.2 ± 2.8% to -0.3 ± 2.1% and from 16.7 ± 10.1% to 2.2 ± 10.6% with [111In]octreotide. Absolute quantitative in vivo SPECT is possible without explicit system matrix measurements. An absolute in vivo quantification error smaller than 5% was achieved and exemplified for both [99mTc]DMSA and [111In]octreotide.
Bert
B
Vandeghinste
Roel
R
Van Holen
Christian
C
Vanhove
Filip
F
De Vos
Stefaan
S
Vandenberghe
Steven
S
Staelens
D000465:Algorithms; D000818:Animals; D002104:Cadmium; D064593:Heterografts; D007091:Image Processing, Computer-Assisted; D007205:Indium Radioisotopes; D007668:Kidney / Q000000981:diagnostic imaging*; D051379:Mice; D015282:Octreotide; D019047:Phantoms, Imaging; D013667:Technetium; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D013691:Tellurium; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation* / Q000379:methods*; D015032:Zinc
C474490:CdZnTe; D007205:Indium Radioisotopes; D002104:Cadmium; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D013667:Technetium; D015032:Zinc; D013691:Tellurium; D015282:Octreotide