2: Formalism and Application of Internal Dosimetry Objective

Sub-module 6.2: Formalism and Application of Internal Dosimetry Objective

To acquire the knowledge and skills of applying established formalisms for internal dosimetry calculations.

Prerequisite

Sub-module 1.2: Basic principles of radiation biology and epidemiology Competencies An understanding of the formalism established for internal dose calculations,

addressed

including its limitations. Ability to calculate absorbed dose to organs according to the MIRD

formalism as well as to derive the effective dose.

Core

• Identifying the physical and biological parameters for absorbed dose

Knowledge

calculation. • Choosing the proper methods of data collection. • Identifying the factors affecting the absorbed dose to particular organs. • Understanding biokinetic analysis and modelling and the fundamentals

of compartment analysis. • Understanding the MIRD formalism so that calculation of absorbed and effective dose can be made for different clinical investigations. • Understanding the uncertainties involved in the various steps. • Estimating the absorbed dose to foetus. • Fundamental understanding of cellular dosimetry (optional).

Recommended • Review the definitions of absorbed dose, equivalent dose and effective

Elements of

dose.

Training

• Choose various nuclear medicine procedures, including paediatric procedures. Describe the measurements required to calculate organ cumulative activity for this procedure. Describe how these measurements could be performed using equipment available in your department. Describe the uncertainties involved.

• Using measured or published biokinetic data, calculate the cumulative activity for the important source organs, in the chosen procedure. Compare the results with the dose information provided by the distributing company for that radiopharmaceutical.

• Search the literature for examples of papers where individual dosimetry has been done. Note the methods for data acquisition. • Evaluate how clinical examinations with a scintillation camera can be designed in order to constitute the basis for an absorbed dose estimate. What data and how many measurements are needed? What other sources can be useful to support the acquired data?

• Study the available literature on estimates of foetal dose from different radiopharmaceuticals, based on standardized kinetic models. Specifically investigate the case of a foetal thyroid dose after the radioiodine (I-131) administration to a woman in a different period of gestation. Search also the literature to explore how the above dose assessment changes in hyperthyroid or athyroid patients.

Knowledge

[1] AMERICAN ASSOCIATION OF PHYSICISTS IN MEDICINE,

Sources

Radiolabelled Antibody Tumor Dosimetry (Reprinted from Medical Physics, Vol. 20, Issue 2), AAPM Rep. 40, New York (1993). http://www.aapm.org/pubs/reports/RPT_40.pdf.

[2] AMERICAN ASSOCIATION OF PHYSICISTS IN MEDICINE, A Primer for Radioimmunotherapy and Radionuclide Therapy, AAPM Rep. 71, New York (2001). http://www.aapm.org/pubs/reports/RPT_71.pdf.

[3] CHERRY, S.R., SORENSON, J.A., PHELPS, M.E., Physics in Nuclear Medicine, 3rd edn, WB Saunders, Philadelphia (2003).

[4] LOEVINGER, R., BUDINGER, T.F., WATSON, E.E., MIRD Primer for Absorbed Dose Calculations, Revised, The Society of Nuclear Medicine (1991).

[5] SGOUROS, G., Dosimetry of internal emitters, J Nucl Med 46 Suppl 1 (2005) 18S-27S.

[6] STABIN, M.G., Radiation Protection and Dosimetry: An Introduction to Health Physics, Springer (2007).

[7] STABIN, M.G., BRILL, A.B., State of the art in nuclear medicine dose assessment, Semin Nucl Med 38 5 (2008) 308-20.

[8] RUSSELL, J.R., STABIN, M.G., SPARKS, R.B., WATSON, E.E., Radiation Absorbed Dose to the Embryo/Foetus from Radiopharmaceuticals, Health Physics 73 3 (1997) 756-769.

[9] STABIN, M.G., WATSON, E.E., MARCUS, C.S., SALK, R.D., Radiation dosimetry for the adult female and foetus from iodine-131 administration in hyperthyroidism, J Nucl Med 32 (1991) 808-813.