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Titolo:
Virtual PMTs: Improving centroid positioning performance near the edges ofa gamma camera detector
Autore:
Vaska, P; Petrillo, MJ; Muehllehner, G;
Indirizzi:
ADAC UGM, Philadelphia, PA 19104 USA ADAC UGM Philadelphia PA USA 19104ADAC UGM, Philadelphia, PA 19104 USA ADAC Labs, Milpitas, CA 95035 USA ADAC Labs Milpitas CA USA 95035ADAC Labs, Milpitas, CA 95035 USA
Titolo Testata:
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
fascicolo: 3, volume: 48, anno: 2001,
parte:, 2
pagine: 645 - 649
SICI:
0018-9499(200106)48:3<645:VPICPP>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Keywords:
data acquisition; position measurement; positron emission tomography (PET); scintillation detectors; single-photon emission computed tomography (SPECT);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
6
Recensione:
Indirizzi per estratti:
Indirizzo: Vaska, P Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA Brookhaven Natl Lab Upton NY USA 11973 Med, Upton, NY 11973 USA
Citazione:
P. Vaska et al., "Virtual PMTs: Improving centroid positioning performance near the edges ofa gamma camera detector", IEEE NUCL S, 48(3), 2001, pp. 645-649

Abstract

The radiation detector used in typical gamma cameras and NaI-based positron emission tomography (PET) scanners effectively positions events over mostof its crystal area, but the spatial resolution begins to suffer at the edges. One reason is that the measured light distribution is truncated or otherwise asymmetric, and the centroid positioning algorithm no longer optimally weights the photomultiplier tube (PMT) signals in this case. As a result, events less than a certain distance from the edge must be rejected, reducing geometric efficiency and complicating image reconstruction for PET systems with multiple fixed detectors. Short of discarding the centroid algorithm altogether, a computationally simple way to improve the positioning is to define a strip of physically nonexistent, or virtual, PMTs around the actual PMTs and to assign realistic signal values to them event by event basedon the signals of nearby real PMTs. If the centroid algorithm now also includes the virtual PMTs, improved spatial resolution is obtained due to better weighting of the PMT signals. With minimal modification to the detector,the virtual PMT method was implemented and tested on an ADAC UGM C-PET detector and found to significantly improve spatial resolution near the detector edges.

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Documento generato il 25/01/20 alle ore 19:07:02