Nuclear Medicine Instrumentation - Image Characteristics and Performance Measures

This set of flashcards covers key concepts related to planar imaging in nuclear medicine, focusing on image characteristics, performance measures, and factors affecting imaging quality.

Planar Images

Two-dimensional images where activity at depth is superimposed, affecting clarity.

Contrast

Ability to visualize relative differences in count density based on biodistribution, lesion size, noise, and resolution.

Uniformity

Ability to create an image showing uniform response to a uniform radioactive distribution; measured daily with a flood image.

Sensitivity

Ability of a gamma camera to efficiently use all available photons in a given time period; depends on scintillation crystal thickness, gamma ray energy, and collimator.

Spatial Resolution

Ability of a gamma camera to reproduce details of a non-uniform radioactive distribution; improved by increasing counts and digital zoom.

Modulation Transfer Function (MTF)

Measure of gamma camera quality that compares image contrast to object contrast; indicates imaging performance.

Line Spread Function (LSF)

Quantitative expression of resolution obtained from a count profile; measures resolution and is converted to mm or cm.

Photon Attenuation

Absorption or re-direction of gamma rays that removes them from the image, affecting overall image quality.

Patient Motion

Causes blurring in images, affecting diagnostic quality.

Counts/Time

Refers to the number of counts registered in a given time; impacts image quality and noise.