Table of Contents
What is a gamma camera used for?
Diagnostic Procedures The gamma camera, also called scintillation camera, is the most commonly used imaging device in nuclear medicine. It simultaneously detects radiation from the entire FOV and enables the acquisition of dynamic as well as static images of the area of interest in the human body [67].
What is gamma camera resolution?
Gamma cameras have a spatial resolution of 3 to 5 mm. Use of a scintillation crystal for acquisition of data for image formation has led to the labeling of this technique as scintigraphy.
What are the two most important QC procedures that must be performed on a scintillation gamma camera?
QC of Planar Imaging Systems Changes in photopeak location, photomultiplier tube (PMT) performance, energy and linearity correction, etc all affect image uniformity. Hence this is probably the single most important QC test that can be performed on a gamma camera system and one that should be performed on a daily basis.
What is matrix size in gamma camera?
With a large field-of-view gamma camera (<::500 mm) a 256 x 256 matrix is required to obtain a pixel of that dimension. Since spot views often have high count densities, the word mode (16-bit pixels) is used.
What are the basic components of gamma camera?
The main components of a gamma camera are:
- the sodium iodide crystal;
- the collimator; and.
- the photomultiplier tubes.
What is a collimator in a gamma camera?
A collimator is the first processing layer of a gamma camera to encounter photons from radioactive source. It restricts the rays from the source so that each point in the image corresponds to a unique point in the source.
What is uniformity of gamma camera?
γ-camera uniformity is defined as the ability to produce a uniform image in response to a uniform source of γ-radiation, with acceptable percentage nonuniformity analyses in the 1%–3% range (3).
What is pixel size in gamma camera?
This implies that the pixel size should be no larger than 3 mm. If the gamma camera field of view is 380 mm, this would require a 128 x 128 matrix (3 mm pixel) or a 64 x 64 matrix with a zoom factor of at least 2. If the pixel size is coarser than this, the spatial resolution.
How is an image produced in a gamma camera?
Gamma cameras are made of a crystal (sodium iodide) which produces a burst of light when gamma rays hit it. Light is picked up by detectors (photomultiplier tubes) located behind the crystal. Electrical output from detectors is fed to computer to produce image.
What are the parts of a gamma camera?
The major components of typical gamma camera are hardware collimator, scintillation crystal, PMTs, preamplifier, amplifier, pulse height analyzer (PHA), position circuitry, computer system for data acquisition including signal processing and correction, and ultimately a monitor for image display and analysis.
What is flood field uniformity?
The intrinsic flood-field uniformity is one of the quality control procedures to evaluate the response of a gamma camera to a spatially uniform flux of an incident gamma radiation over the field of view.
What is gamma in camera settings?
Gamma defines how the numerical value of a pixel relates to its actual brightness. While gamma is extremely difficult to understand in its entirety, digital photographers need to understand how it applies to images. Gamma dramatically affects how a digital image looks on a computer screen.
What is intrinsic flood?
What is center of rotation in spect?
Center of Rotation artifact: The detectors of a SPECT camera rotate around a central axis. The computer makes assumptions about the location of this axis during image reconstruction. The center of rotation corrects for the difference between the center of the computer matirx and the projection of the cameras face.
What is gamma camera imaging and quality control?
Basic Principles of Gamma Camera Imaging and Quality Control Sharon L. White, PhD University of Alabama at Birmingham July 16, 2015 Page 2 Disclosures No financial disclosures. Gamma camera images and photographs of equipment are for illustrating concepts and not intended to advertise or endorse any particular manufacturer or vendor.
What is gamma camera imaging of radioactive sources in patients?
Gamma Camera Imaging of Radioactive Sources in Patients Three major Components: 1. Collimator – localizes γ-ray source in patient 2. NaI (Tl)Crystal (single or multi-crystal) over width of patient stops the γ-rays. 3. Array of PMT’s – localizes γ-ray interaction in crystal 2. Collimator Types 3.
What is the uniformity of gamma camera?
Uniformity measurement is one of the parts of quality control of Gamma Camera. The uniformity measurements may be intrinsic or extrinsic. The intrinsic measurements are carried out without col- limator and the extrinsic measurements are carried out with collimator
What should be included in a gamma camera performance report?
List performance characteristics of gamma cameras and features affecting performance. 3. List basic gamma camera calibrations and how they affect performance. 4. List QC tests for gamma cameras required by accrediting organizations. 5. Describe how to perform basic QC tests and assess acceptable performance.
The gamma camera is a machine that allows two-dimensional imaging of physical processes within the body using a radiopharmaceutical. A radiopharmaceutical is a drug to which radioactive atoms are attached so the location where the drug is concentrating in the body can be easily detected.
What is the resolution of a gamma camera?
Gamma cameras have a spatial resolution of 3 to 5 mm. Use of a scintillation crystal for acquisition of data for image formation has led to the labeling of this technique as scintigraphy. Thallium-doped sodium iodide crystal produces light when stimulated by gamma or x-ray photons
How are gamma photons used in X-ray imaging?
The high-energy gamma photons meet a detector called a scintillation crystal, which converts them into light. This light is then amplified and processed by the camera to reveal the distribution of the radiopharmaceutical in two dimensions.
What radioisotopes are used in gamma cameras?
A tomographic version of the gamma camera is called SPECT, which yields slices through the body. Because the detection techniques of gamma cameras and SPECT are based on the same concept, the same radioisotopes can be used for both techniques. Commonly used isotopes include technetium-99m, iodine-123, and indium-111. Simon R. Cherry PhD,