Abstract
In a previous paper, a portal imaging system was described that used a 101 mm diameter, 3 mm thick CsI(Tl) transparent scintillating screen coupled to a liquid-nitrogen-cooled slow-scan CCD-TV camera with a 40 mm f1.0 macro lens with a 5:1 demagnification. Meanwhile, improved images have been acquired using a 50 mm f1.1 macro lens with a 7:1 demagnification. These images were presented at an AAPM International Symposium on Electronic Portal Imaging in Detroit, MI, in May, 1997. Since the Detroit meeting, a 203 mm diameter, 13 mm thick CsI(Tl) crystal has been purchased from Bicron. This transparent screen has been used with a Nikkor 35 mm f1.4 lens to show the whole 203 mm circular field at 0.53 mm pixel size with the existing Astromed liquid nitrogen cooled CCD TV camera system. The geometry of the imaging system has been optimized to achieve high spatial resolution (1 lp/mm) in spite of the increased thickness of the screen. This increased thickness allows the high image quality achieved with the older screen at 72MU to be maintained with the newer screen while reducing the dose to 1MU. Images have been acquired with the new screen of lead bar patterns, low-contrast hole patterns in Lucite blocks, and anthropomorphic phantoms.
Original language | English (US) |
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Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |
Editors | J.T. Dobbins III, J.M. Boone |
Pages | 175-186 |
Number of pages | 12 |
Volume | 3336 |
DOIs | |
State | Published - 1998 |
Event | Medical Imaging 1998: Physics of Medical Imaging - San Diego, CA, United States Duration: Feb 22 1998 → Feb 24 1998 |
Other
Other | Medical Imaging 1998: Physics of Medical Imaging |
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Country/Territory | United States |
City | San Diego, CA |
Period | 2/22/98 → 2/24/98 |
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Condensed Matter Physics