title: Repeatability of Radiotracer Uptake in Normal Abdominal Organs with ¹¹¹In-Pentetreotide Quantitative SPECT/CT.
abstract: With an increasing emphasis on quantitation of SPECT imaging and its use in dosimetry to guide therapies, it is desirable to understand the repeatability in normal-organ SPECT uptake values (SPECT-UVs). We investigated the variability of normal abdominal organ uptake in repeated (111)In-pentetreotide SPECT studies.
  
  
  METHODS
  Nine patients with multiple (111)In-pentetreotide SPECT/CT studies for clinical purposes were evaluated. Volumes of interest were drawn for the abdominal organs and applied to SPECT-UVs. The variability of those values was assessed.
  
  
  RESULTS
  The average SPECT-UV for the liver (1.7 ± 0.6) was much lower than for the kidneys (right, 8.0 ± 2.4; left, 7.5 ± 1.7). Interpatient and intrapatient variability was similar (intraclass correlation coefficients, 0.40-0.59) for all organs. The average coefficients of variation for each organ for each patient were obtained and averaged across all patients (0.26 for liver, 0.22 for right kidney, and 0.20 for left kidney). The coefficients of variation for the organs across all scans were 0.33 (liver), 0.30 (right kidney), and 0.22 (left kidney).
  
  
  CONCLUSIONS
  Variability across all patients and all scans for the liver was higher than reported with (18)F-FDG PET, though left kidney variability was similar to PET liver variability and left kidney uptake may be able to serve as an internal metric for determining the quantifiability of an (111)In-pentetreotide SPECT study.
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Rowe
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Esther
authors.initials: E
authors.lastname: Vicente
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Nadège
authors.initials: N
authors.lastname: Anizan
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Leal
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Lodge
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Frey
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland wahlr@mir.wustl.edu.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Wahl
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes; D007668:Kidney / Q000000981:diagnostic imaging; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging; D011829:Radiation Dosage; D011874:Radiometry; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: D007205:Indium Radioisotopes; D019275:Radiopharmaceuticals; D013004:Somatostatin; C081788:pentetreotide
keywords: 111In-pentetreotide SPECT; SPECT-UV; dosimetry; quantitative SPECT