Chapter 6: Gamma Camera - Performance Characteristics

13 flashcards · Biology · by Kristóf Nagy

Photopeak
The peak in an energy spectrum corresponding to the full energy deposition of the incident gamma ray in the detector78.
Intrinsic Resolution
The inherent resolution limit of a scintillator material due to statistical fluctuations in the number of visible photons produced per unit of deposited gamma ray energy26. This is proportional to 1/E𝛾2.
Efficiency/Sensitivity
The ability of a detector to detect gamma rays34. In the 100-200 keV range, a gamma camera has an efficiency of 50-100%3.
Contrast
Concerns the weakest observable object with a given background13.
Spatial resolution
Concerns the smallest observable object12.
Standard Deviation
A measure of the spread or dispersion of data points around the mean value6.
Gaussian Distribution
A bell-shaped probability distribution used to approximate the Poisson distribution for large numbers of events, allowing for the calculation of the standard deviation of the mean6.
Poisson Statistics
Describes the probability distribution of events occurring randomly in time or space, particularly relevant for the statistical nature of photon detection, impacting energy resolution56. For large N, the Poisson distribution can be approximated by a Gaussian6.
Double Scattering Events
When a gamma ray scatters twice within the detector system, leading to a misinterpretation of the event's location as centered between the two scatter points4.
Countrate
The number of gamma rays detected per unit time4.
Energy Resolution
A measure of a detector’s ability to distinguish between gamma rays of different energies45.
Backscatter Peak
A peak in the energy spectrum caused by gamma rays that have undergone Compton scattering outside the detector and then backscattered into the detector with a reduced energy8.
Compton Edge
The maximum energy that can be transferred to a recoil electron in a Compton scattering event, leading to a sharp edge in the energy spectrum8.