Design and performance of a positron-sensitive surgical probe / Fang Liu.

Format:

Book

Manuscript

Microformat

Thesis/Dissertation

Author/Creator:

Liu, Fang.

Contributor:

Karp, Joel S., advisor.

Lockyer, Nigel S., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Physics and astronomy.

Physics and astronomy--Penn dissertations.

Local Subjects:

Penn dissertations--Physics and astronomy.

Physics and astronomy--Penn dissertations.

Physical Description:

xi, 173 pages : illustrations ; 29 cm

Production:

2003.

Summary:

We report the design and performance of a portable positron-sensitive surgical imaging probe. The probe is designed to be sensitive to positrons and capable of rejecting background gammas including 511 keV. The probe consists of a multi-anode PMT and an 8 x 8 array of thin 2 mm x 2 mm plastic scintillators coupled 1:1 to GSO crystals. The probe uses three selection criteria to identify positrons. An energy threshold on the plastic signals reduces the false positron signals in the plastic due to background gammas; a second energy threshold on the PMT sum signal greatly reduces background gammas in the GSO. Finally, a timing window accepts only 511 keV gammas from the GSO that arrive within 15 ns of the plastic signals, reducing accidental coincidences to a negligible level. The first application being investigated is sentinel lymph node (SLN) surgery, to identify in real-time the location of SLNs in the axilla with high 18F-FDG uptake, which may indicate metastasis. Our simulations and measurements show that the probe's pixel separation ability in terms of peak-to-valley ratio is ∼3.5. The performance measurements also show that the 64-pixel probe has a sensitivity of 4.7 kcps/muCi using optimal signal selection criteria. For example, it is able to detect in 10 seconds a ∼4 mm lesion with a true-to-background ratio of ∼3 at a tumor uptake ratio of ∼8:1. The signal selection criteria can be fine-tuned, either for higher sensitivity, or for a higher image contrast.

Notes:

Supervisors: Joel S. Karp; Nigel S. Lockyer.

Thesis (Ph.D. in Physics and Astronomy) -- University of Pennsylvania, 2003.

Includes bibliographical references.

Local Notes:

University Microfilms order no.: 3095913.

OCLC:

244973018