Image-reconstruction algorithms for positron-emission tomography systems

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5012836

Cheng, S N.C.

The positional uncertainty in the time-of-flight measurement of a positron-emission tomography system is modelled as a Gaussian distributed random variable and the image is assumed to be piecewise constant on a rectilinear lattice. A reconstruction algorithm using maximum-likelihood estimation is derived for the situation in which time-of-flight data are sorted as the most-likely-position array. The algorithm is formulated as a linear system described by a nonseparable, block-banded, Toeplitz matrix, and a sine-transform technique is used to implement this algorithm efficiently. The reconstruction algorithms for both the most-likely-position array and the confidence-weighted array are described by similar equations, hence similar linear systems can be used to described the reconstruction algorithm for a discrete, confidence-weighted array, when the matrix and the entries in the data array are properly identified. It is found that the mean square-error depends on the ratio of the full width at half the maximum of time-of-flight measurement over the size of a pixel. When other parameters are fixed, the larger the pixel size, the smaller is the mean square-error. In the study of resolution, parameters that affect the impulse response of time-of-flight reconstruction algorithms are identified. It is found that the larger the pixel size, the larger is the standard deviation of the impulse response. This shows that small mean square-error and fine resolution are two contradictory requirements.

• OSTI ID: 5012836
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ALGORITHMS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
ELEMENTARY PARTICLES
EMISSION COMPUTED TOMOGRAPHY
FERMIONS
IMAGES
LEPTONS
MATHEMATICAL LOGIC
OPTIMIZATION
POSITRON COMPUTED TOMOGRAPHY
POSITRONS
TIME-OF-FLIGHT METHOD
TOMOGRAPHY