Statistics of Radiation Events

Mind Map


Learning Activities

Visuals for



Outline and Learning Guide


1.      Introduction and Overview

1.1.   The Random Nature of Radiation Events

1.1.1.      Radioactive Emissions

1.1.2.      Photon Interactions

1.1.3.      Photon Distributions Within an Area

1.2.   Effects of Random Events

1.2.1.      Errors in Measurement of Radioactivity

1.2.2.      Source of Visual Noise in Images

2.      The Statistical Distribution of Events

2.1.   Concept and Description

2.2.   Gaussian Distributions

2.3.   Standard Deviations

3.      Errors in Individual Events

3.1.   Concept and Relation to Mean (Average) Value

3.2.   Error Ranges and Standard Deviations

3.3.   Probability of Events Within Specific Error Ranges

4.      Standard Deviation (SD)

4.1.   Poisson Distribution Characteristics

4.2.   Relationship of SD to the Mean of a Distribution

4.3.   Calculating an Estimated Value for the SD

4.4.   Relationship of SD to Number of Photons

4.4.1.      Counted in the Measurement of Radioactivity

4.4.2.      Captured to Form an Image

5.      SD and Errors for Combined Collections of Photons

5.1.   Calculation of SD for Combined Collections

5.2.   SD and Errors Increased by Subtraction

5.2.1.      Applies When Subtracting Background in Radioactive Counting

5.2.2.      Increases Image Noise in Digital Subtraction Angiography (DSA)

5.3.    SD Decreased by Adding, Averaging, or Integrating  Collections of Photons

5.3.1.      Decreases Perceived Noise in Human Viewed Fluoroscopic Images

5.3.2.      Applied in Digital Processing of Images to Reduce Noise

6.      Summary and Review of Clinical Applications