NMD-04

Percent injected dose

%ID = 100 A_organ / A_inj. Fraction of the injection in an organ.

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Uptake%ID

Governing equation

\%\mathrm{ID}=100\,A_{\mathrm{organ}}/A_{\mathrm{inj}}

$A_{org} \in \left[0.1, 400\right]$

where

A_{org}: Organ activity (MBq)
A_{inj}: Injected activity (MBq)
\%ID: Percent injected dose (%)

The figure, part by part

Each numbered marker wears the color of its card. Hover a card to light the marker. Tap a marker to jump to that card. The slider walks a red point along the curve; Animate drawing traces it like a pen.

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①

Governing law — red

\%\mathrm{ID}=100\,A_{\mathrm{organ}}/A_{\mathrm{inj}}

$A_{org} \in \left[0.1, 400\right]$

$A_{org} = 0.1$ $\%ID = 0.027$

Along the curve

②

Domain of the variable — blue

A_{org}_{\min} = 0.1,\quad A_{org}_{\max} = 400

$A_{org} \in \left[0.1, 400\right]$

$A_{org} = 0.1$ $A_{org} = 0.1$

Along the curve

③

Response curve — green

\%\mathrm{ID}=100\,A_{\mathrm{organ}}/A_{\mathrm{inj}}

$A_{org} \in \left[0.1, 400\right]$

$A_{org} = 0.1$ $\%ID = 0.027$

Along the curve

④

Rate of change — amber

\frac{\mathrm{d}\%ID}{\mathrm{d}A_{org}}

$A_{org} \in \left[0.1, 400\right]$

$A_{org} = 2.615$ $\%ID^{\prime} = 0.27$

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-04 — Percent injected dose) is the form associated with %ID. Working symbols: $A_{org}$ , $A_{inj}$ $\rightarrow$ $\%ID$ . Decay-correct the organ counts back to injection time before dividing. %ID/g is the density version.

Purpose

Purpose: compute

\%ID

from

A_{org}

A_{inj}

in Nuclear medicine via

\%\mathrm{ID}=100\,A_{\mathrm{organ}}/A_{\mathrm{inj}}

%ID = 100 A_organ / A_inj. Fraction of the injection in an organ. 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

A_{org} = 40.000\,\mathrm{MBq}

A_{inj} = 370.000\,\mathrm{MBq}

, the governing relation

\%\mathrm{ID}=100\,A_{\mathrm{organ}}/A_{\mathrm{inj}}

yields

\%ID = 10.81\,\mathrm{%}

. A syringe, an organ, a percentage. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Organ activity A_{org}40 MBqInjected activity A_{inj}370 MBq

Outputs

Percent injected dose \%ID10.81 %

Reading speed

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Narration of this film

A syringe, an organ, a percentage.

Decay-correct the organ counts back to injection time before dividing. %ID/g is the density version.

Reading speed

Watch on YouTube