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The Medical Internal Radiation Dose (MIRD) Committee was formed in 1965 "to provide medical and scientific communities with the most accurate estimate of the dose that a patient receives from radiopharmaceuticals administered for diagnostic studies" (l). The committee's charter was to "collect, collate, and evaluate metabolic, chemical and nuclear data on various radiopharmaceuticals and merge this information into a realistic estimate of the patient dose using the most appropriate dose calculation techniques." At its founding, Monte Blau, PhD, and Ed Smith, DSc, served as cochairs, and the initial membership also included John McAfee, MD, Richard Peterson, MD, James Robertson, MD, PhD, and Henry Wagner, Jr.. MD. Mones Berman, PhD, Robert Loevinger, PhD, and Gordon L. Brownell, PhD, served as consultants to the committee. The group agreed that the mission of the committee would be the technical evaluation of dose and not the evaluation of hazards, efficacy, and other such topics as "critical" organ dose.
Early committee discussions focused on moving away from assumptions of uniform distributions of activity throughout the whole body and also on establishing a unified approach to performing dosimetry. The results of these efforts. published as MIRD Pamphlet No. 1 (Loevinger and Berman, 1968), revolutionized dosimetry by abandoning the use of the roentgen as a unit and devising a formulation that no longer used the specific 7-ray constant, G, and the geometric factor, g, in absorbed dose calculations. In subsequent pamphlets, the MIRD Committee introduced the concepts of absorbed fraction and S value that now form the basis for almost all radionuclide dosimetry and that are embedded in such popular dosimetry software as OLINDA (2). Even more recently, the MIRD formalism has been extended to cellular and subcellular source and target regions, with the publication of a volume tabulating cellular S values (3).
Forty years after the publication of MIRD Pamphlet No. 1, the MIRD Committee is engaged in an expansion of its mission. To address the requirements of therapeutic nuclear medicine and the emerging use of α-particle-emitting radionuclides, the committee is moving beyond "the technical evaluation of dose" for diagnostic studies and is cautiously espousing radiobiological modeling to help translate absorbed dose to biological effects for therapeutic studies. The committee has taken the first step in this direction with the recently...