RT Journal Article SR Electronic T1 MIRD Pamphlet No. 23: Quantitative SPECT for Patient-Specific 3-Dimensional Dosimetry in Internal Radionuclide Therapy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1310 OP 1325 DO 10.2967/jnumed.111.100123 VO 53 IS 8 A1 Yuni K. Dewaraja A1 Eric C. Frey A1 George Sgouros A1 A. Bertrand Brill A1 Peter Roberson A1 Pat B. Zanzonico A1 Michael Ljungberg YR 2012 UL http://jnm.snmjournals.org/content/53/8/1310.abstract AB In internal radionuclide therapy, a growing interest in voxel-level estimates of tissue-absorbed dose has been driven by the desire to report radiobiologic quantities that account for the biologic consequences of both spatial and temporal nonuniformities in these dose estimates. This report presents an overview of 3-dimensional SPECT methods and requirements for internal dosimetry at both regional and voxel levels. Combined SPECT/CT image-based methods are emphasized, because the CT-derived anatomic information allows one to address multiple technical factors that affect SPECT quantification while facilitating the patient-specific voxel-level dosimetry calculation itself. SPECT imaging and reconstruction techniques for quantification in radionuclide therapy are not necessarily the same as those designed to optimize diagnostic imaging quality. The current overview is intended as an introduction to an upcoming series of MIRD pamphlets with detailed radionuclide-specific recommendations intended to provide best-practice SPECT quantification–based guidance for radionuclide dosimetry.