title: Microsphere localization and dose quantification using positron emission tomography/CT following hepatic intraarterial radioembolization with yttrium-90 in patients with advanced hepatocellular carcinoma.
abstract: OBJECTIVE
  To characterize the distribution of absorbed radiation dose after glass microsphere radioembolization for hepatocellular carcinoma (HCC) using yttrium-90 ((90)Y) positron emission tomography/computed tomography (PET/CT).
  
  
  METHODS
  In this retrospective study, 64 (90)Y PET/CT scans performed after treatment were evaluated following (90)Y glass-bead radioembolization in patients with advanced HCC. The intended dose to the target volume ranged from 83-129 Gy. Three-dimensional "dose maps" were created from reconstructed PET images using a voxel-based S-value transformation. Liver parenchyma and liver tumors were contoured on cross-sectional imaging and aligned with the created dose maps.
  
  
  RESULTS
  There were 113 tumors examined as part of 64 lobar treatments. The average tumor size was 4.8 cm ± 4.0 with an average tumor dose of 173 Gy ± 109. The average dose to the nontumor parenchyma within the target volume was 93.4 Gy ± 32.6, with on average 50% of the parenchymal voxels receiving > 79 Gy ± 23 and 10% receiving > 173 Gy ± 55. The average and median tumor-to-parenchymal weighted dose ratios were 2.2 and 1.9, respectively.
  
  
  CONCLUSIONS
  Using recommended dosimetry and administration techniques for lobar glass microsphere radioembolization, high doses to target tumors as well as background parenchyma were achieved on average with modest preferential uptake within tumors. There was wide variation in measured tumor and parenchymal doses after hepatic radioembolization for HCC, suggesting the need for continued development of patient-specific dosimetry.
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University, 550 N. University Boulevard, Room 0663, Indianapolis, IN 46202.
authors.forename: William B
authors.initials: WB
authors.lastname: Lea
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University, 550 N. University Boulevard, Room 0663, Indianapolis, IN 46202; School of Health Sciences, Purdue University, West Lafayette, Indiana.
authors.forename: Katie N
authors.initials: KN
authors.lastname: Tapp
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University, 550 N. University Boulevard, Room 0663, Indianapolis, IN 46202.
authors.forename: Mark
authors.initials: M
authors.lastname: Tann
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University, 550 N. University Boulevard, Room 0663, Indianapolis, IN 46202.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Hutchins
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University, 550 N. University Boulevard, Room 0663, Indianapolis, IN 46202.
authors.forename: James W
authors.initials: JW
authors.lastname: Fletcher
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University, 550 N. University Boulevard, Room 0663, Indianapolis, IN 46202. Electronic address: matjohns@iupui.edu.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Johnson
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D004621:Embolization, Therapeutic / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005898:Glass; D006499:Hepatic Artery; D006801:Humans; D007269:Injections, Intra-Arterial; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000009:adverse effects; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden; D015021:Yttrium Radioisotopes / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes