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Title: Optimizing Pinhole and Parallel Hole Collimation for Scintimammography with Compact Pixellated Detectors

Abstract

The relative advantages of pinhole and parallel hole collimators for scintimammography with compact, pixellated gamma detectors were investigated using analytic models of resolution and sensitivity. Collimator design was studied as follows. A desired object resolution was specified for a pixellated detector with a given crystal size and intrinsic spatial resolution and for a given object-to-collimator distance. Using analytic formulas, pinhole and parallel hole collimator parameters were calculated that satisfy this object resolution with optimal geometric sensitivity. Analyses were performed for 15 cm x 20 cm field of view detectors with crystal elements 1.0, 2.0 and 3.0 mm on a side and 140 keV incident photons. The sensitivity for a given object resolution was greater for pinhole collimation at smaller distances, as expected. The object distance at which the pinhole and parallel hole sensitivity curves cross each other is important. The crossover distances increased with larger crystal size for a constant object resolution and increased as the desired object resolution decreases for a constant crystal size. For example, for 4 mm object resolution these distances were 5.5 cm, 6.5 cm and 8 cm for the 1 mm, 2 mm and 3 mm crystal detectors, respectively. The results suggest a strategy ofmore » parallel hole collimation for whole breast imaging and pinhole collimation for imaging focal uptake. This could be accomplished with a dual detector system with a different collimator type on each head or a single head system equipped with two collimators and a rapid switching mechanism. Multipinhole collimators have the potential to increase sensitivity yet maintain high image resolution. An experimental SPECT phantom study with a four-pinhole collimator was acquired with a pixellated detector. The iterative maximum-likelihood expectation- maximization (MLEM) reconstruction of a hot sphere in a warm cylinder showed the potential of multipinhole collimation to improve sensitivity for tomographic pinhole scintimammography.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
805767
Report Number(s):
JLAB-PHY-02-64; DOE/ER/40150-2403
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Conference
Resource Relation:
Conference: 2002 IEEE Nuclear Science Symposium and Medical Imaging Conference, Norfolk, VA (US), 11/2002; Other Information: PBD: 1 Nov 2002
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Smith, Mark F, Kieper, Douglas A, Majewski, Stan, Weisenberger, Andrew G, and Welch, Benjamin. Optimizing Pinhole and Parallel Hole Collimation for Scintimammography with Compact Pixellated Detectors. United States: N. p., 2002. Web.
Smith, Mark F, Kieper, Douglas A, Majewski, Stan, Weisenberger, Andrew G, & Welch, Benjamin. Optimizing Pinhole and Parallel Hole Collimation for Scintimammography with Compact Pixellated Detectors. United States.
Smith, Mark F, Kieper, Douglas A, Majewski, Stan, Weisenberger, Andrew G, and Welch, Benjamin. Fri . "Optimizing Pinhole and Parallel Hole Collimation for Scintimammography with Compact Pixellated Detectors". United States. https://www.osti.gov/servlets/purl/805767.
@article{osti_805767,
title = {Optimizing Pinhole and Parallel Hole Collimation for Scintimammography with Compact Pixellated Detectors},
author = {Smith, Mark F and Kieper, Douglas A and Majewski, Stan and Weisenberger, Andrew G and Welch, Benjamin},
abstractNote = {The relative advantages of pinhole and parallel hole collimators for scintimammography with compact, pixellated gamma detectors were investigated using analytic models of resolution and sensitivity. Collimator design was studied as follows. A desired object resolution was specified for a pixellated detector with a given crystal size and intrinsic spatial resolution and for a given object-to-collimator distance. Using analytic formulas, pinhole and parallel hole collimator parameters were calculated that satisfy this object resolution with optimal geometric sensitivity. Analyses were performed for 15 cm x 20 cm field of view detectors with crystal elements 1.0, 2.0 and 3.0 mm on a side and 140 keV incident photons. The sensitivity for a given object resolution was greater for pinhole collimation at smaller distances, as expected. The object distance at which the pinhole and parallel hole sensitivity curves cross each other is important. The crossover distances increased with larger crystal size for a constant object resolution and increased as the desired object resolution decreases for a constant crystal size. For example, for 4 mm object resolution these distances were 5.5 cm, 6.5 cm and 8 cm for the 1 mm, 2 mm and 3 mm crystal detectors, respectively. The results suggest a strategy of parallel hole collimation for whole breast imaging and pinhole collimation for imaging focal uptake. This could be accomplished with a dual detector system with a different collimator type on each head or a single head system equipped with two collimators and a rapid switching mechanism. Multipinhole collimators have the potential to increase sensitivity yet maintain high image resolution. An experimental SPECT phantom study with a four-pinhole collimator was acquired with a pixellated detector. The iterative maximum-likelihood expectation- maximization (MLEM) reconstruction of a hot sphere in a warm cylinder showed the potential of multipinhole collimation to improve sensitivity for tomographic pinhole scintimammography.},
doi = {},
url = {https://www.osti.gov/biblio/805767}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {11}
}

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