Nuclear Medicine and Imaging Review

This collection of flashcards covers key concepts from the lecture notes on nuclear medicine and imaging modalities, including definitions, principles, and specific details related to radiation dosages and imaging technologies.

What does the CT number represent in a CT system?

The spatial resolution of a CT system.

What is the approximate radiation dose of a chest X-ray?

0.1 mSv.

What is the role of collimators in imaging?

To reduce scatter and improve image resolution.

What is the function of FDG in PET scans?

FDG is used to detect metabolic activity in tissues.

What is the typical range of CT number for fat tissue?

-1000 to -500.

Describe the principle of nuclear imaging.

Injecting unstable isotopes into the body to allow for detection of gamma rays for imaging.

What is a scintillator?

A material used in detectors that produces light when exposed to gamma rays.

What is the half-life of Oxygen-15 labelled water?

2.04 minutes.

How are radioactive isotopes created for medical use?

Using cyclotrons, nuclear reactors, or linear accelerators to accelerate particles to create unstable isotopes.

What type of decay does an unstable isotope undergo?

Radioactive decay to stabilize into other nuclei.

How long is the half-life of Carbon isotopes?

5370 years.

What is the result of a positron emission during nuclear decay?

Annihilation with an electron and the release of two gamma rays.

Why is FDG used for tumor detection in PET scans?

Tumors have higher metabolic activity and thus uptake more glucose.

What is the definition of uptake in the context of nuclear medicine?

The absorption of a substance by a living organism or organ.

What type of rays do gamma rays typically emit from radioactive decay?

High-energy gamma rays.

How does the presence of longer anti-scatter grids affect image quality?

It may increase signal-to-noise ratio while potentially decreasing overall signal intensity.

Which imaging modality uses direct detectors?

Some nuclear medicine systems.

What defines nuclear medicine?

The use of radioactive isotopes to identify regions of uptake or metabolic activity.

What happens to positrons during positron decay?

They annihilate with electrons, producing gamma rays.

What do photomultiplier tubes do in nuclear medicine detectors?

They amplify the signals from scintillators to detect gamma rays.

What is the approximate average radiation dose from a CT scan?

30 mSv.

What defines the decay constant in radioactive decay?

It’s a constant that describes the rate at which a radioactive isotope decays.