MIRD Pamphlet No. 28, Part 1: MIRDcalc—A Software Tool for Medical Internal Radiation Dosimetry

Abstract

Medical internal radiation dosimetry constitutes a fundamental aspect of diagnosis, treatment, optimization, and safety in nuclear medicine. The MIRD committee of the Society of Nuclear Medicine and Medical Imaging developed a new computational tool to support organ-level and suborgan tissue dosimetry (MIRDcalc, version 1). Based on a standard Excel spreadsheet platform, MIRDcalc provides enhanced capabilities to facilitate radiopharmaceutical internal dosimetry. This new computational tool implements the well-established MIRD schema for internal dosimetry. The spreadsheet incorporates a significantly enhanced database comprising details for 333 radionuclides, 12 phantom reference models (International Commission on Radiological Protection), 81 source regions, and 48 target regions, along with the ability to interpolate between models for patient-specific dosimetry. The software also includes sphere models of various composition for tumor dosimetry. MIRDcalc offers several noteworthy features for organ-level dosimetry, including modeling of blood source regions and dynamic source regions defined by user input, integration of tumor tissues, error propagation, quality control checks, batch processing, and reportpreparation capabilities. MIRDcalc implements an immediate, easy-touse single-screen interface. The MIRDcalc software is available for free download (www.mirdsoft.org) and has been approved by the Society of Nuclear Medicine and Molecular Imaging.

The risk index as a basis for risk/benefit analyses and protocol optimization in diagnostic nuclear imaging

“…The calculation of RI for different radiopharmaceuticals, begins with estimates of the organ‐specific absorbed doses. To achieve this, we utilized reference radiopharmaceutical time‐integrated activity coefficients published in ICRP Publication 128 19 as input, calculations were performed using MIRDcalc software, 14 which yielded organs absorbed dose, E , E DW , LAR, and RI as output. The number of source regions used in each calculation was dependent on how the biokinetic data were provided in ICRP publication 128, but typically 4−8.…”

“…Of note, the RI calculation for radiopharmaceutical applications is integrated into the newly released MIRDcalc nuclear medicine dosimetry software, 14 freely available at http://www.mirdsoft.org (example use cases of RI can be found in the MIRDcalc manual).…”

131I dose coefficients for a reference population using age-specific models

“…Earlier studies have shown variations in effective doses due to photons, electron [20] and 18 F-FDG [21] estimated using a voxel-based model from those estimated using stylized phantoms. The UF/NCI and PRC phantoms have been used to compute SAF values for electrons and photons of various energies [22][23][24], which in turn are used to compute S values and organ doses for medical intake scenarios [24,25]. These studies only focus on dose computation for medical protection pathways such as intravenous and oral administration, while leaving out the inhalation pathway required for radiological protection.…”

Addendum to MIRD Pamphlet No. 28

“…TO THE EDITOR: The journal has recently published MIRD pamphlet no. 28, parts 1 and 2, which describe and provide validation for the nuclear medicine software code MIRDcalc, part of the MIRDsoft.org series of freely accessible software for the field of nuclear medicine (1,2). We wish this letter to serve as an addendum clarifying an important technical aspect of the work in regard to some of the graphical presentations of the library of phantom computational models used to generate radionuclide S values, which form the computational engine of organ dosimetry in the MIRDcalc code.…”