NMD-17

Energy-window width

W% = 100 ΔE / E0. Photopeak window as a percent of E0.

Reading speed

SpectroscopyEnergy window

Governing equation

W_{\%}=100\,\Delta E/E_0

where

\Delta E: Full window ΔE (keV)
E_0: Photopeak energy (keV)
W: Window percent (%)

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-17 — Energy-window width) is the form associated with Energy window. Working symbols: $\Delta E$ , $E_0$ $\rightarrow$ $W$ . A 20 % window on 140 keV is ±14 keV. Narrower windows cut scatter and also cut photopeak counts.

Purpose

Purpose: compute

W

from

\Delta E

E_0

in Nuclear medicine via

W_{\%}=100\,\Delta E/E_0

W% = 100 ΔE / E0. Photopeak window as a percent of E0. 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

\Delta E = 28.000\,\mathrm{keV}

E_0 = 140.000\,\mathrm{keV}

, the governing relation

W_{\%}=100\,\Delta E/E_0

yields

W = 20.00\,\mathrm{%}

. A photopeak and a pair of energy cursors. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Full window ΔE \Delta E28 keVPhotopeak energy E_0140 keV

Outputs

Window percent W20.00 %

Reading speed

Watch on YouTube

Free library

Full library

Free PDF / open book

YouTube channels

00:0 / 00:08

Narration of this film

A photopeak and a pair of energy cursors.

A 20 % window on 140 keV is ±14 keV. Narrower windows cut scatter and also cut photopeak counts.

Reading speed

Watch on YouTube