Quantitative uptake measurements of I-131 (364 keV) within the tomographic plane of a specially collimated SPECT system
The use of SPECT for uptake measurements requires a linear relationship between the measured counts within a tomographic plane and its activity distribution. Many factors influence this relationship, and these include filter type and attenuation correction methods. However, for higher photon energy (I-131, 364 keV), photon penetration through the collimator or detector shielding may degrade, for example, the tomographic plane and slice thickness resolution and the ability to differentiate activity within a slice and between slices. A SPECT system (Picker International Dyna Camera), equipped with a specialized (low sensitivity) thick septa collimator for I-131 (364 keV) and 511 keV detector shielding is proposed for quantitative measurements. The influence of photon penetration was significantly reduced, with transverse plane and slice thickness resolution of 18 mm FWHM and 37 mm FWIM for a radius of rotation of 14 cm. Iodine collimators typically have FWTM 5-10 times the FWHM. A Jaszczak phantom was imaged with I-131, with two bar quadrants observed with diameters of 16 and 12.7 mm. The SPECT resolution data was equal to a low energy general purpose collimator. A multi-concentric ring (contrast) phantom was designed to quantitatively evaluate the SPECT system. A linear relationship was observed between the measured counts for a transverse plane and I-131 activity within the rings. Data suggest that with appropriate collimation and detector shielding SPECT systems may be used for quantitative measurements at higher photon energy.
- Research Organization:
- Univ. of Miami, Miami, FL
- OSTI ID:
- 6843570
- Report Number(s):
- CONF-840619-; TRN: 87-008872
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
61 RADIATION PROTECTION AND DOSIMETRY
IODINE 131
UPTAKE
PHANTOMS
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
COLLIMATORS
SHIELDING
ATTENUATION
KEV RANGE 100-1000
OPTICAL FILTERS
PHOTONS
RESOLUTION
ROTATION
SENSITIVITY
THICKNESS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COMPUTERIZED TOMOGRAPHY
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DIMENSIONS
ELEMENTARY PARTICLES
EMISSION COMPUTED TOMOGRAPHY
ENERGY RANGE
FILTERS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KEV RANGE
MASSLESS PARTICLES
MOCKUP
MOTION
NUCLEI
ODD-EVEN NUCLEI
RADIOISOTOPES
STRUCTURAL MODELS
TOMOGRAPHY
550602* - Medicine- External Radiation in Diagnostics- (1980-)
440101 - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments
655003 - Medical Physics- Dosimetry