NMD-05

PET coincidence rate

R = 2 ε² g A. Geometric efficiency g times paired detection.

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PETPET coincidence

Governing equation

R=2\varepsilon^{2} g A

where

A: Activity (MBq)
\varepsilon: Crystal efficiency (—)
g: Geometric factor (—)
R: Coincidence rate (kcps)

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-05 — PET coincidence rate) is the form associated with PET coincidence. Working symbols: $A$ , $\varepsilon$ , $g$ $\rightarrow$ $R$ . Trues, scatter and randoms share the coincidence window. NECR is the figure of merit.

Purpose

Purpose: compute

R

from

A

\varepsilon

g

in Nuclear medicine via

R=2\varepsilon^{2} g A

R = 2 ε² g A. Geometric efficiency g times paired detection. 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 = 150.000\,\mathrm{MBq}

\varepsilon = 0.200\,\mathrm{—}

g = 0.080\,\mathrm{—}

, the governing relation

R=2\varepsilon^{2} g A

yields

R = 960.00\,\mathrm{kcps}

. A ring of crystals and a positron source. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Activity A150 MBqCrystal efficiency \varepsilon0.2 —Geometric factor g0.08 —

Outputs

Coincidence rate R960.00 kcps

Reading speed

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Narration of this film

A ring of crystals and a positron source.

Trues, scatter and randoms share the coincidence window. NECR is the figure of merit.

Reading speed

Watch on YouTube