NMD-28

Percent ID per gram

%ID/g = %ID / m. Biodistribution density.

Reading speed

Uptake%ID/g

Governing equation

\%\mathrm{ID/g}=\%\mathrm{ID}/m

$m \in \left[0.1, 400\right]$

where

\%ID: Percent injected dose (%)
m: Organ mass (g)
\%ID/g: Percent ID per gram (%/g)

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/g}=\%\mathrm{ID}/m

$m \in \left[0.1, 400\right]$

$m = 0.1$ $\%ID/g = 40$

Along the curve

②

Domain of the variable — blue

m_{\min} = 0.1,\quad m_{\max} = 400

$m \in \left[0.1, 400\right]$

$m = 0.1$ $m = 0.1$

Along the curve

③

Response curve — green

\%\mathrm{ID/g}=\%\mathrm{ID}/m

$m \in \left[0.1, 400\right]$

$m = 0.1$ $\%ID/g = 40$

Along the curve

④

Rate of change — amber

\frac{\mathrm{d}\%ID/g}{\mathrm{d}m}

$m \in \left[0.1, 400\right]$

$m = 2.615$ $\%ID/g^{\prime} = -7.797$

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-28 — Percent ID per gram) is the form associated with %ID/g. Working symbols: $\%ID$ , $m$ $\rightarrow$ $\%ID/g$ . Preclinical papers quote %ID/g. SUV is the human cousin that folds in body weight.

Purpose

Purpose: compute

\%ID/g

from

\%ID

m

in Nuclear medicine via

\%\mathrm{ID/g}=\%\mathrm{ID}/m

%ID/g = %ID / m. Biodistribution density. 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

\%ID = 4.000\,\mathrm{%}

m = 20.000\,\mathrm{g}

, the governing relation

\%\mathrm{ID/g}=\%\mathrm{ID}/m

yields

\%ID/g = 0.2000\,\mathrm{%/g}

. An organ mass and a percent of the injection. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Percent injected dose \%ID4 %Organ mass m20 g

Outputs

Percent ID per gram \%ID/g0.2000 %/g

Reading speed

Watch on YouTube

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Narration of this film

An organ mass and a percent of the injection.

Preclinical papers quote %ID/g. SUV is the human cousin that folds in body weight.

Reading speed

Watch on YouTube