An automated voxelized dosimetry tool for radionuclide therapy based on serial quantitative SPECT/CT imaging. Issue 11 (10th October 2013)

• Record Type: Journal Article
• Authors: Jackson, Price A.; Beauregard, Jean‐Mathieu; Hofman, Michael S.; Kron, Tomas; Hogg, Annette; Hicks, Rodney J.
• Is Part Of: Medical physics. Volume 40:Issue 11(2013)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2013-10-10
• Subjects: Dosimetry/exposure assessment -- Therapeutic applications, including brachytherapy -- Monte Carlo simulations -- Registration -- Computed tomography -- Single photon emission computed tomography (SPECT); deformation -- dosimetry -- image registration -- kidney -- liver -- medical image processing -- Monte Carlo methods -- neurophysiology -- radiation therapy -- radioisotopes -- single photon emission computed tomography -- tumours; dosimetry protocols -- nuclear medicine -- image processing; Radiation therapy -- Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Scintigraphy -- Measuring radioactive content of objects, e.g. contamination (whole‐body counters G01T011/63); Dosimetry -- Medical imaging -- Single photon emission computed tomography -- Anatomy -- Computed tomography -- Tissues -- Cancer -- Image registration -- Liver -- Computer software; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4824318
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: : To create an accurate map of the distribution of radiation dose deposition in healthy and target tissues during radionuclide therapy. Methods: : Serial quantitative SPECT/CT images were acquired at 4, 24, and 72 h for 28 177 Lu‐octreotate peptide receptor radionuclide therapy (PRRT) administrations in 17 patients with advanced neuroendocrine tumors. Deformable image registration was combined with an in‐house programming algorithm to interpolate pharmacokinetic uptake and clearance at a voxel level. The resultant cumulated activity image series are comprised of values representing the total number of decays within each voxelˈs volume. For PRRT, cumulated activity was translated to absorbed dose based on Monte Carlo‐determined voxel S‐values at a combination of long and short ranges. These dosimetric image sets were compared for mean radiation absorbed dose to at‐risk organs using a conventional MIRD protocol (OLINDA 1.1). Results: : Absorbed dose values to solid organs (liver, kidneys, and spleen) were within 10% using both techniques. Dose estimates to marrow were greater using the voxelized protocol, attributed to the software incorporating crossfire effect from nearby tumor volumes. Conclusions: : The technique presented offers an efficient, automated tool for PRRT dosimetry based on serial post‐therapy imaging. Following retrospective analysis, this method of high‐resolution dosimetry may allow physicians to prescribe activity based on required dose to tumor volume or radiation limits to healthy tissue in individual patients.