NMD-01

MIRD absorbed dose

D = Ã S. Cumulated activity times the S-value of the source–target pair.

Reading speed

Internal dosimetryMIRD

Governing equation

D=\tilde A\, S

$\tilde A \in \left[1, 5000\right]$

where

\tilde A: Cumulated activity (MBq·h)
S: S-value (mGy/MBq/h)
D: Absorbed dose (mGy)

The figure, part by part

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①

Governing law — red

D=\tilde A\, S

$\tilde A \in \left[1, 5000\right]$

$\tilde A = 1$ $D = 0.05$

Along the curve

②

Domain of the variable — blue

\tilde A_{\min} = 1,\quad \tilde A_{\max} = 5000

$\tilde A \in \left[1, 5000\right]$

$\tilde A = 1$ $\tilde A = 1$

Along the curve

③

Response curve — green

D=\tilde A\, S

$\tilde A \in \left[1, 5000\right]$

$\tilde A = 1$ $D = 0.05$

Along the curve

④

Rate of change — amber

\frac{\mathrm{d}D}{\mathrm{d}\tilde A}

$\tilde A \in \left[1, 5000\right]$

$\tilde A = 32.44$ $D^{\prime} = 0.05$

Along the curve

Lecture brief

Historical brief

MIRD schema, in-vivo decay, uptake fractions and PET coincidence turned unsealed sources into organ dose. The sheets compute activity, residence and well-counter geometry. This sheet (NMD-01 — MIRD absorbed dose) is the form associated with MIRD. Working symbols: $\tilde A$ , $S$ $\rightarrow$ $D$ . Ã = ∫A(t) dt. S folds geometry, yield and absorbed fractions into mGy/MBq/h.

Purpose

Purpose: compute

D

from

\tilde A

S

in Nuclear medicine via

D=\tilde A\, S

D = Ã S. Cumulated activity times the S-value of the source–target pair. Use it when a real nuclear medicine question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

\tilde A = 200.000\,\mathrm{MBq·h}

S = 0.050\,\mathrm{mGy/MBq/h}

, the governing relation

D=\tilde A\, S

yields

D = 10.00\,\mathrm{mGy}

. A source organ, a target, a dose. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Cumulated activity \tilde A200 MBq·hS-value S0.05 mGy/MBq/h

Outputs

Absorbed dose D10.00 mGy

Reading speed

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Narration of this film

A source organ, a target, a dose.

Ã = ∫A(t) dt. S folds geometry, yield and absorbed fractions into mGy/MBq/h.

Reading speed

Watch on YouTube