Design and construction of a prototype rotation modulation collimator for near-field high-energy spectroscopic gamma imaging

Published

Journal Article

Neutron Stimulated Emission Computed Tomography (NSECT) is being developed for in vivo measurement of the concentration and location of biologically relevant elements. NSECT is a spectroscopic imaging technique whereby the body is illuminated via high-energy neutrons that excite elemental nuclei that then relax through characteristic gamma radiation. This imaging technique requires high-resolution spectroscopy, thereby eliminating the use conventional scintillation gamma cameras. Consequently, high-purity germanium (HPGe) semi-conductor detectors are utilized, providing no spatial information. To obtain 2D elemental concentration images, we are adapting high-energy solar spectroscopy technology. A rotating modulation collimator (RMC) consisting of two parallel-slat collimators is placed in front of the detector to modulate the incoming signal in a manner predicted by its geometry. Reconstruction of 2D images is feasible by counting the number of incident gammas at each rotation angle. The challenge is to identify a RMC geometry that allows this method to work in the near-field environment, which has far fewer assumptions and simplifications than the infinite focus of solar imaging. Herein we describe construction of a prototype RMC and experiments conducted with a radioactive 22Na point source. These experiments verified that the RMC modulates the signal in manner consistent with its geometric and physical properties. © 2006 IEEE.

Full Text

Duke Authors

Cited Authors

  • Sharma, AC; Tourassi, GD; Kapadia, AJ; Harrawood, BP; Bender, JE; Crowell, AS; Kiser, MR; Howell, CR; Floyd, CE

Published Date

  • December 1, 2007

Published In

Volume / Issue

  • 4 /

Start / End Page

  • 2021 - 2024

International Standard Serial Number (ISSN)

  • 1095-7863

Digital Object Identifier (DOI)

  • 10.1109/NSSMIC.2006.354310

Citation Source

  • Scopus