Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2010-3-15
pubmed:abstractText
Reported values of D(2) receptor occupancy (RO) achieved by antipsychotic drugs tend to be lower when measured with (123)I-IBZM SPECT than with (11)C-Raclopride PET. Image degrading factors such as attenuation, distance-dependent collimator response and scatter could account for this difference. While attenuation correction is routinely applied to SPECT images, the other degradations are not usually accounted for. The aim of this work was to assess the impact of scatter correction on D(2) RO quantification with (123)I-IBZM SPECT, and to compare the results of both corrected and un-corrected SPECT values with (11)C-Raclopride PET measurements. Phantom experiments as well as within-subject human data from a previous study were used for this purpose. SPECT images were reconstructed using filtered back-projection including attenuation correction (FBP(A)), ordered subsets expectation maximization including attenuation and point spread function corrections (OSEM(A+PSF)) and ordered subsets expectation maximization including attenuation, point spread function and scatter corrections (OSEM(A+PSF+SCT)). PET images were reconstructed using the FBP algorithm and corrected for attenuation, scatter, random coincidences and dead time. Quantification of receptor availability was performed using the tissue ratio at pseudoequilibrium for SPECT, and the simplified reference tissue model (SRTM) for PET. Analysis was performed using both occipital cortex (occ) and cerebellum (cer) as reference regions for both modalities. When images were reconstructed using FBP(A), SPECT D(2) RO values were significantly lower as compared with PET leading to a D(2) RO difference of -20% (CI(95%): -13, -27%) (occ) and -23% (CI(95%): -14, -31%) (cer). When images were reconstructed using OSEM(A+PSF), SPECT D(2) RO values were also lower as compared with PET leading to a D(2) RO difference of -21% (CI(95%): -14, -27%) (occ) and -24% (CI(95%): -18, -30%) (cer). When images were reconstructed using OSEM(A+PSF+SCT), the D(2) RO bias was reduced to -6% (CI(95%): 0, -13%) (occ) and -11% (CI(95%): -4, -18%) (cer). These data suggest that the scatter correction plays a major role in explaining the differences between D(2) RO measurements using (123)I-IBZM SPECT and (11)C-Raclopride PET.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1095-9572
pubmed:author
pubmed:copyrightInfo
Crown Copyright 2010. Published by Elsevier Inc. All rights reserved.
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1511-8
pubmed:meshHeading
pubmed-meshheading:20083205-Adult, pubmed-meshheading:20083205-Algorithms, pubmed-meshheading:20083205-Antipsychotic Agents, pubmed-meshheading:20083205-Benzamides, pubmed-meshheading:20083205-Brain, pubmed-meshheading:20083205-Brain Mapping, pubmed-meshheading:20083205-Female, pubmed-meshheading:20083205-Humans, pubmed-meshheading:20083205-Image Processing, Computer-Assisted, pubmed-meshheading:20083205-Magnetic Resonance Imaging, pubmed-meshheading:20083205-Male, pubmed-meshheading:20083205-Models, Neurological, pubmed-meshheading:20083205-Phantoms, Imaging, pubmed-meshheading:20083205-Positron-Emission Tomography, pubmed-meshheading:20083205-Pyrrolidines, pubmed-meshheading:20083205-Raclopride, pubmed-meshheading:20083205-Receptors, Dopamine D2, pubmed-meshheading:20083205-Scattering, Radiation, pubmed-meshheading:20083205-Signal Processing, Computer-Assisted, pubmed-meshheading:20083205-Tomography, Emission-Computed, Single-Photon
pubmed:year
2010
pubmed:articleTitle
Impact of scatter correction on D2 receptor occupancy measurements using 123I-IBZM SPECT: comparison to 11C-Raclopride PET.
pubmed:affiliation
Neurosciences Imaging Group, Molecular Imaging Centre (CRC-CIM), Barcelona Biomedical Research Park, C/ Dr. Aiguader 88, soterrani-1, 08003 Barcelona, Spain. sbullich@crccorp.es
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't