[Creation and Evaluation of Educational Programs for Additional Delayed Scan of FDG-PET/CT].

Unlabelled: Generally, FDG-PET/CT image is acquired at the 60th minute after tracer administration. Depending on the clinical case, additional delayed scans may be useful. However, it is difficult to judge whether additional delayed scan is useful or not.

Quantitative CBF measurement using an integrated SPECT/CT system: validation of three-dimensional ordered-subset expectation maximization and CT-based attenuation correction by comparing with O-15 water PET.

Rationale And Objectives: As spreading integrated SPECT/CT scanners, reconstruction method based on three-dimensional ordered-subset expectation maximization (3D-OSEM) with attenuation correction (AC) using an X-ray CT image (CTAC) is easily available in brain imaging. For quantitative cerebral blood flow (CBF) measurements, however, the accuracy of this method has not been fully evaluated clinically. To validate this new algorithm, we sequentially studied quantitative PET-CBF and SPECT-CBF measurements in the same healthy volunteers and compared CBF values.

[Difference of orbit by rotation direction at automatic contouring SPECT using electrostatic capacitance sensor: effect of updating the software].

Automatic contouring system using electrostatic capacitance sensor can sense electrostatic capacitance between a detector and patients' side space. So the system can be set it at an arbitrary distance. On the other hand, this system is so complicated that it is difficult to forecast the detector motion.

Metallic artifacts caused by dental metal prostheses on PET images: a PET/CT phantom study using different PET/CT scanners.

Objective: The objective of this study was to investigate the effects of computed tomography (CT) artifacts caused by dental metal prostheses on positron emission tomography (PET) images.

Methods: A dental arch cast was fixed in a cylindrical water-bath phantom. A spherical phantom positioned in the vicinity of the dental arch cast was used to simulate a tumor.

Usefulness of noise adaptive non-linear gaussian filter in FDG-PET study.

Objective: In positron emission tomography (PET) studies, shortening transmission (TR) scan time can improve patient comfort and increase scanner throughput. However, PET images from short TR scans may be degraded due to the statistical noise included in the TR image. The purpose of this study was to apply non-linear Gaussian (NLG) and noise adaptive NLG (ANLG) filters to TR images, and to evaluate the extent of noise reduction by the ANLG filter in comparison with that by the NLG filter using phantom and clinical studies.

Assessment of acetazolamide reactivity in cerebral blood flow using spectral analysis and technetium-99m hexamethylpropylene amine oxime.

Cerebral blood flow (CBF) can be quantified noninvasively using the brain perfusion index (BPI), determined from radionuclide angiographic data generated with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO). Previously, the BPI has been calculated using graphical analysis (GA); however, the GA method is greatly affected by the first-pass extraction fraction and retention fraction, which are not only variable, but lower in cases with an increased CBF, such as after the administration of acetazolamide. Thus, GA-calculated BPI values (BPIG) may not reflect the absolute CBF.