MIRD Pamphlet No. 28, Part 2: Comparative Evaluation of MIRDcalc Dosimetry Software Across a Compendium of Diagnostic Radiopharmaceuticals

Abstract

Radiopharmaceutical dosimetry is usually estimated via organ-level MIRD schema-style formalisms, which form the computational basis for commonly used clinical and research dosimetry software. Recently, MIRDcalc internal dosimetry software was developed to provide a freely available organ-level dosimetry solution that incorporates upto-date models of human anatomy, addresses uncertainty in radiopharmaceutical biokinetics and patient organ masses, and offers a 1-screen user interface as well as quality assurance tools. The present work describes the validation of MIRDcalc and, secondarily, provides a compendium of radiopharmaceutical dose coefficients obtained with MIRDcalc. Biokinetic data for about 70 currently and historically used radiopharmaceuticals were obtained from the International Commission on Radiological Protection (ICRP) publication 128 radiopharmaceutical data compendium. Absorbed dose and effective dose coefficients were derived from the biokinetic datasets using MIRDcalc, IDAC-Dose, and OLINDA software. The dose coefficients obtained with MIRDcalc were systematically compared against the other software-derived dose coefficients and those originally presented in ICRP publication 128. Dose coefficients computed with MIRDcalc and IDAC-Dose showed excellent overall agreement. The dose coefficients derived from other software and the dose coefficients promulgated in ICRP publication 128 both were in reasonable agreement with the dose coefficients computed with MIRDcalc. Future work should expand the scope of the validation to include personalized dosimetry calculations.

Dosimetry of [18F]TRACK, the first PET tracer for imaging of TrkB/C receptors in humans

“…With appropriate adjustment of the injected dose, these dosimetry results will allow for repeated measurements in the same subjects without exceeding dose limitations in most jurisdictions (Jackson et al 2020 ), which may be of interest when studying TrkB/C receptor density in neurodegeneration or during recovery from focal brain injury. The dosimetry model used in this study (Carter et al 2021 ; Kesner et al 2018 ) on average accounted for 89.7% of injected activity with the residual activity accumulated below the knees outside the field of view and to some extent at the wall of the injection tubing due to lipophilicity of the tracer.…”

“…The radiation doses absorbed by the target organs from surrounding source organs were calculated using the MIRD method (Cherry et al 2012 ). The absorbed target organ dose per unit activity is the sum of the cumulated activity in each of the source organs multiplied by a dose factor (S-value) in units of Gy/Bq*s (MIRD-Calc software V1.1-Genesis (Carter et al 2021 ; Kesner et al 2018 )). The effective (E) and detriment weighted dose (E DW ) for each subject were obtained by summation of the equivalent dose multiplied by the organ specific weighting factors.…”

First-in-human evaluation of 6-bromo-7-[11C]methylpurine, a PET tracer for assessing the function of multidrug resistance-associated proteins in different tissues

“…PET frame images were analysed using an in-house pipeline (built using the Python programming language) to extract TACs for each region. Absorbed doses were calculated using the Medical Internal Radiation Dose (MIRD) methodology [20] with the MIRDcalc software for organ level dosimetry [21,22]. The standard adult male and female International Commission on Radiological Protection (ICRP) reference phantoms were used for organ masses and source to target organ dose values (S values).…”

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.…”