title: VIDA: a voxel-based dosimetry method for targeted radionuclide therapy using Geant4.
abstract: We have developed the Voxel-Based Internal Dosimetry Application (VIDA) to provide patient-specific dosimetry in targeted radionuclide therapy performing Monte Carlo simulations of radiation transport with the Geant4 toolkit. The code generates voxel-level dose rate maps using anatomical and physiological data taken from individual patients. Voxel level dose rate curves are then fit and integrated to yield a spatial map of radiation absorbed dose. In this article, we present validation studies using established dosimetry results, including self-dose factors (DFs) from the OLINDA/EXM program for uniform activity in unit density spheres and organ self- and cross-organ DFs in the Radiation Dose Assessment Resource (RADAR) reference adult phantom. The comparison with reference data demonstrated agreement within 5% for self-DFs to spheres and reference phantom source organs for four common radionuclides used in targeted therapy ((131)I, (90)Y, (111)In, (177)Lu). Agreement within 9% was achieved for cross-organ DFs. We also present dose estimates to normal tissues and tumors from studies of two non-Hodgkin Lymphoma patients treated by (131)I radioimmunotherapy, with comparison to results generated independently with another dosimetry code. A relative difference of 12% or less was found between methods for mean absorbed tumor doses accounting for tumor regression.
authors.affiliation: 1 Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee.
authors.forename: Susan D
authors.initials: SD
authors.lastname: Kost
authors.forename: Yuni K
authors.initials: YK
authors.lastname: Dewaraja
authors.forename: Richard G
authors.initials: RG
authors.lastname: Abramson
authors.forename: Michael G
authors.initials: MG
authors.lastname: Stabin
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007457:Iodine Radioisotopes / Q000008:administration & dosage; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D009010:Monte Carlo Method; D057285:Precision Medicine / Q000379:methods; D011834:Radiation Monitoring / Q000379:methods; D011868:Radioisotopes / Q000008:administration & dosage*; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes
keywords: 3D dosimetry; Monte Carlo; SPECT/CT; patient-specific dosimetry; radioimmunotherapy