I-125 dose calc formulae? -Reply

[FRAMEP@ORAU.GOV]

I passed this question on to Mike Stabin here at ORISE. When it comes to
internal dosimetry, they don't come much, if any, better. Note the problem
with the chemical form of the ingested iodine.  Also, he provides the
bottom line (i.e. the doses) but does not show the actual calculations
which would be a huge task.  If I have time tomorrow, and nobody else
does it, I'll see if I can crank out an example calculation for the thyroid.

Paul Frame
framep@orau.gov

Forwarded message:

Paul -

Here is our most recent dosimetry for I-125 **sodium iodide**.  If the
problem has to to with I-125 tagged to some sort of other compound or
pharmaceutical, as suggested by the problem, the dosimetry will of
course be much different.  I don't know if I have dosimetry for many
different RIA compounds.  If the person is really serious and wants to
contact me and give me the actual compound, I will check.

September 18, 1992

Radiation Dose Estimates for I-125 Sodium Iodide

                                    Estimated Radiation Dose
                                          mGy                rad  
ORGAN                             MBq                mCi                   
Adrenals                        1.1E-02            4.0E-02
Brain                              1.3E-02            4.7E-02
Breasts                          6.2E-03            2.3E-02
Gallbladder Wall             1.9E-02            6.8E-02
LLI Wall                          1.1E-02            4.2E-02
Small Intestine                3.7E-02            1.4E-01
Stomach                         6.4E-02            2.4E-01
ULI Wall                          1.5E-02            5.5E-02
Heart Wall                       9.1E-03            3.4E-02
Kidneys                          8.6E-03            3.2E-02
Liver                               8.6E-02            3.2E-01
Lungs                             1.9E-02            7.1E-02
Muscle                            8.6E-02            3.2E-01
Ovaries                           1.1E-02            4.1E-02
Pancreas                        1.3E-02            4.9E-02
Red Marrow                   1.7E-02            6.3E-02
Bone Surfaces               9.9E-02            3.6E-01
Skin                                 1.7E-02            6.4E-02
Spleen                            8.4E-03            3.1E-02
Testes                            6.5E-03            2.4E-02
Thymus                          2.4E-02            8.9E-02
Thyroid                           2.1E+02            7.8E+02
Urinary Bladder Wall      1.2E-01            4.4E-01
Uterus                            1.4E-02            5.2E-02

Effective Dose Equivalent             6.4E+00 mSv/MBq    2.4E+01 rem/mCi


Based on model in MIRD Dose Estimate Report No. 5, J Nucl Med
16:857-860, 1975 (25% thyroid uptake). Estimate calculated using
phantom of Cristy & Eckerman (Report ORNL/TM-8381/V1 & V7)

Radiation Internal Dose
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