Collimator selection and I-124 contamination determination for I-123 imaging studies

Conference · Sun Jan 01 04:00:00 EST 1984 · J. Nucl. Med.; (United States)

OSTI ID:7090373

Madsen, M T; Patel, J; Thakur, M L; Park, C H

The use of I-123 as an imaging agent is increasing. Because of the high energy photons from contaminant I-124 compromise the quality of I-123 images, it is important to determine the amount of I-124 and to carefully evaluate the imaging system. The authors have developed an automatic method which yields an accurate, precise and rapid means of assessing I-124 contamination. The fraction of I-124 is determined by comparing counts in the 604 keV peak to the counts in the I-123 159 keV peak from spectra acquired on a computer based multichannel analyzer linked to a Ge(Li) detector. The acquisition, peak selection and calculation are performed under program control. The optimal collimation was determined from computer acquired line source images of I-123 positioned above the gamma camera in the presence of scattering material. The system resolution was evaluated for a low energy general purpose collimator (hole size: 2.5mm, septa: 0.3mm, length: 41mm) and a medium energy collimator (2mm, 0.8mm, 25mm). The general purpose collimator has the best performance when I-124 levels are low (less than 3%) or when high contrast objects are imaged with good statistics. The medium energy collimator yields the best results when contamination exceeds 3% and the objects lack high frequency components or when the image is noisy.

• Research Organization: Thomas Jefferson Univ. Hospital, Philadelphia, PA
• OSTI ID: 7090373
• Report Number(s): CONF-840619-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

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62 RADIOLOGY AND NUCLEAR MEDICINE
ACCURACY
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CAMERAS
COLLIMATORS
COMPUTER CALCULATIONS
CONTAMINATION
COUNTING TECHNIQUES
DATA ACQUISITION
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTRONIC EQUIPMENT
ELEMENTARY PARTICLES
ENERGY RANGE
EQUIPMENT
FREQUENCY DEPENDENCE
GAMMA CAMERAS
GE SEMICONDUCTOR DETECTORS
HOURS LIVING RADIOISOTOPES
IMAGE PROCESSING
INTERMEDIATE MASS NUCLEI
IODINE 123
IODINE 124
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KEV RANGE
KEV RANGE 100-1000
LI-DRIFTED DETECTORS
LI-DRIFTED GE DETECTORS
MASSLESS PARTICLES
MEASURING INSTRUMENTS
MULTI-CHANNEL ANALYZERS
NOISE
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
OPTIMIZATION
PHOTONS
POSITIONING
PROCESSING
PULSE ANALYZERS
QUANTITY RATIO
RADIATION DETECTORS
RADIOISOTOPE SCANNING
RADIOISOTOPES
SCATTERING
SEMICONDUCTOR DETECTORS
TRACER TECHNIQUES