OLINDA/EXM (Organ Level INternal Dose Assessment/EXponential Modeling)

OLINDA/EXM is a personal computer code for calculating organ doses and effective doses in nuclear medicine studies was developed in 2004. OLINDA/EXM, which stands for Organ Level INternal Dose Assessment/EXponential Modeling, calculates radiation doses to different organs of the body from systemically administered radiopharmaceuticals and performs regression analysis on user-supplied biokinetic data, to support such calculations.

The OLINDA code was written by Michael Stabin PhD, CHP, who also wrote the MIRDOSE 3.0 and 3.1 codes*, which were widely used in the radiopharmaceutical industry and research community for internal dose calculations for radiopharmaceuticals. MIRDOSE was relied upon for a number of years and was been used by thousands of medical, safety, and regulatory professionals. OLINDA version 1 used basically the same calculational algorithms as MIRDOSE, with some updates, including:

  • Nearly 600 new radionuclides (including alpha emitters)
  • New organ phantoms
  • A revised and improved bone model
  • A code for performing kinetic analysis of biokinetic data (EXM, written by Drs. Richard Sparks and Eric Crowe of CDE, Inc.)
  • The ability to modify organ masses to patient-specific values

Version 2 now has:

  • Over 1000 radionuclides (including alpha emitters)
  • Next generation, voxel-based realistic phantoms for adults, children and pregnant women.
  • Voxel-based realistic phantoms for 3 mouse, 5 rat, and 2 dog models.
  • The ability to modify organ masses to patient-specific values
  • The ability assign activity to the walls of hollow organs


OLINDA/EXM was designed as an update to MIRDOSE*. Just like for MIRDOSE, users will enter results of kinetic models into the code, which uses them with models of the human body which have been established in the literature to calculate estimates of the radiation dose to all of the organs and the body. The dose factors used in OLINDA are those found on the RADAR page on model dose factors; the technical basis for the factors appeared in the Health Physics Journal (85(3):294-310, 2003). In the EXM portion of the code, however, users can actually perform kinetic analyses, fitting sums of exponentials to data gathered in animal or human studies. The physical models that the code uses are stylized approximations of the human body of idealized average individuals (adult male, adult female, children of various ages, and women at three stages of pregnancy).

The majority of the applications of this code are theoretical applications involving diagnostic applications of radiopharmaceuticals. With the increasing interest in recent years in the use of radiopharmaceuticals in therapy, however, there is an interest in using the code to estimate doses to organs of patients receiving therapy, either retrospectively or perhaps prospectively. Such applications led the US Food and Drug Administration to initially raise concerns about the status of the MIRDOSE software (J Nucl Med, Newsline, Vol. 41, No. 6, June 2000, 13N) possibly being a ‘medical device’, and this has led to the seeking of a premarket notification (510K) for OLINDA/EXM. The clearance for version 1 was sought and was received from the FDA on June 15, 2004 (K033960). Click here to see some sample screens from the software. The code was released by Vanderbilt University and was widely distributed. Version 1 (and 1.1) were withdrawn from the market and is replaced with Version 2, which contains new generation, voxel-based realistic human phantoms based on ICRP 89 reference organ masses. This is being distributed by Hermes MedicalClick here to go to the OLINDA/EXM order page.


Official Website


Tutorials: OverviewVideo Demos, Dose Factors, Sample Screenshots (doc), Computational Phantoms

Reference Paper


* MIDROSE is a software package that had been popular for a number of years for calculating internal radiation dose estimates for radionuclides used in nuclear medicine. The program has phantom libraries which permit the calculation of these doses for individuals of different age and size and for women at different stages of pregnancy. The program did not include libraries of doses for nuclear medicine radiopharmaceuticals. The user needed to calculate the input data that described the biokinetics of a given radiopharmaceutical (from her own animal or human data) or find them in the literature. Kinetic models for different radiopharmaceuticals change often, as new information becomes available and as models change and (hopefully) improve. MIRDOSE was simply a tool which permits the calculation of radiation dose estimates, using the MIRD technique, once the kinetic model was defined.


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