Peak-counts blood flow model-errors and limitations
The peak-counts model has several advantages, but its use may be limited due to the condition that the venous egress may not be negligible at the time of peak-counts. Consequently, blood flow measurements by the peak-counts model will depend on the bolus size, bolus duration, and the minimum transit time of the bolus through the region of interest. The effect of bolus size on the measurement of extraction fraction and blood flow was evaluated by injecting 1 to 30ml of rubidium chloride in the femoral vein of a dog and measuring the myocardial activity with a beta probe over the heart. Regional blood flow measurements were not found to vary with bolus sizes up to 30ml. The effect of bolus duration was studied by injecting a 10cc bolus of tracer at different speeds in the femoral vein of a dog. All intravenous injections undergo a broadening of the bolus duration due to the transit time of the tracer through the lungs and the heart. This transit time was found to range from 4-6 second FWHM and dominates the duration of the bolus to the myocardium for up to 3 second injections. A computer simulation has been carried out in which the different parameters of delay time, extraction fraction, and bolus duration can be changed to assess the errors in the peak-counts model. The results of the simulations show that the error will be greatest for short transit time delays and for low extraction fractions.
- Research Organization:
- Univ. of Texas Health Science Center, Houston, TX
- OSTI ID:
- 6844834
- Report Number(s):
- CONF-840619-; TRN: 87-008778
- 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
59 BASIC BIOLOGICAL SCIENCES
BLOOD FLOW
FLOW MODELS
BLOOD COUNT
EXTRACTION
LUNGS
MYOCARDIUM
RUBIDIUM CHLORIDES
TIME DEPENDENCE
TRACER TECHNIQUES
ALKALI METAL COMPOUNDS
BODY
CARDIOVASCULAR SYSTEM
CHLORIDES
CHLORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HEART
ISOTOPE APPLICATIONS
MATHEMATICAL MODELS
MUSCLES
ORGANS
RESPIRATORY SYSTEM
RUBIDIUM COMPOUNDS
SEPARATION PROCESSES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
551001 - Physiological Systems- Tracer Techniques