Technical Note: Rod phantom analysis for comparison of PET detector sampling and reconstruction methods. Issue 11 (1st November 2016)

• Record Type: Journal Article
• Authors: Wollenweber, Scott D.; Kemp, Brad J.
• Is Part Of: Medical physics. Volume 43:Issue 11(2016)
• Page Start: 6175
• Page End: 6185
• Publication Date: 2016-11-01
• Subjects: dosimetry -- feature extraction -- image denoising -- image reconstruction -- image resolution -- image sampling -- medical image processing -- phantoms -- positron emission tomography; Positron emission tomography (PET) -- Dosimetry/exposure assessment -- Dose‐volume analysis -- Spatial resolution -- Noise -- Reconstruction; Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Image enhancement or restoration, e.g. from bit‐mapped to bit‐mapped creating a similar image -- Scintigraphy -- Measuring half‐life of a radioactive substance; image quality -- positron emission tomography (PET) -- quantification; Image scanners -- Positron emission tomography -- Image reconstruction -- Image sensors -- Medical image reconstruction -- Medical image quality -- Image analysis -- Computed tomography -- Image detection systems; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4964458
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: This investigation aimed to develop a scanner quantification performance methodology and compare multiple metrics between two scanners under different imaging conditions. Most PET scanners are designed to work over a wide dynamic range of patient imaging conditions. Clinical constraints, however, often impact the realization of the entitlement performance for a particular scanner design. Using less injected dose and imaging for a shorter time are often key considerations, all while maintaining "acceptable" image quality and quantitative capability. Methods: A dual phantom measurement including resolution inserts was used to measure the effects of in‐plane ( x, y ) and axial ( z ) system resolution between two PET/CT systems with different block detector crystal dimensions. One of the scanners had significantly thinner slices. Several quantitative measures, including feature contrast recovery, max/min value, and feature profile accuracy were derived from the resulting data and compared between the two scanners and multiple phantoms and alignments. Results: At the clinically relevant count levels used, the scanner with thinner slices had improved performance of approximately 2%, averaged over phantom alignments, measures, and reconstruction methods, for the head‐sized phantom, mainly demonstrated with the rods aligned perpendicular to the scanner axis. That same scanner had a slightly decreased performance of −1% for the larger body‐size phantom, mostly due to an apparent noise increase in the images. Most of the differences in the metrics between the two scanners were less than 10%. Conclusions: Using the proposed scanner performance methodology, it was shown that smaller detector elements and a larger number of image voxels require higher count density in order to demonstrate improved image quality and quantitation. In a body imaging scenario under typical clinical conditions, the potential advantages of the design must overcome increases in noise due to lower count density.