Nuclear Medicine Instrumentation - Collimators

These flashcards cover key terms and concepts related to collimators in nuclear medicine instrumentation.

Collimator

An instrument that defines the field of view and rejects unwanted photons in nuclear medicine.

Septa

The walls between the holes of a collimator that absorb off-angle gamma rays.

Absorptive Collimation

A type of collimation that eliminates unwanted gamma rays by passive absorption in the collimator.

Gamma Camera

A device used in nuclear medicine to create images based on the gamma radiation emitted by radiopharmaceuticals.

Sensitivity of a Collimator

Defined as the number of counts per minute the gamma camera receives per microcurie of activity.

Resolution

The ability to distinguish between two separate objects or points in an image.

Parallel-Hole Collimator

A common type of collimator with channels that are perpendicular to the imaging plane and produce images of the same size as the source.

Pinhole Collimator

A collimator used to image small organs with a superior resolution in the magnified image.

Converging Collimator

Designed for imaging small organs, with channels arranged in oblique angles that produce a magnified image.

Diverging Collimator

A type of collimator that diverges the field of view to image larger organs, often creating a minified image.

Energy Ratings of Collimators

Classification of collimators based on their ability to detect different ranges of gamma photon energy.

Septal Thickness

The thickness of the walls separating the holes in a collimator, affecting the absorption of higher-energy gamma rays.

Field of View (FOV)

The observable area that a collimator captures in imaging.

Image Distortion

Occurs when the object is magnified to different degrees at different depths, particularly in the converging/diverging collimators.