Journal article
Measuring PET Spatial Resolution Using a Cylinder Phantom Positioned at an Oblique Angle
The Journal of nuclear medicine (1978), Vol.59(11), pp.1768-1775
11/2018
DOI: 10.2967/jnumed.118.209593
PMCID: PMC6225537
PMID: 29903932
Abstract
A cylinder phantom positioned at a slightly oblique angle with respect to the
z
-axis of a PET scanner allows for fine sampling of the edge-spread function. We show how this technique can be used to measure the spatial resolution that can be expected with clinical PET protocols, potentially providing more relevant estimates than are typically obtained with established experimental procedures.
Methods:
A 20-cm-diameter water-filled cylinder phantom containing a uniform
18
F solution was centrally positioned at a small angle with respect to the
z
-axis of a clinical PET/CT system. The oblique angle ensures that the phantom edge intersects the image matrix differently in different slices. Combining line profiles from multiple slices results in a composite profile with fine sampling. Spatial resolution was measured as the full width at half maximum (FWHM) by fitting a model to the finely sampled edge-spread functions in both radial and axial directions. The technique was validated by controlled modulation of image reconstruction parameters and by comparison with extended phantoms with fillable inserts. Separate experiments with uniform cylinders containing
18
F,
11
C,
13
N,
68
Ga, and
124
I were used to further assess the proposed method.
Results:
Controlled adjustment of a gaussian postreconstruction filter was accurately reflected in the measured FWHM values. Recovery coefficients derived using the cylinder FWHM values agreed closely with recovery coefficients derived from physical phantoms over a range of insert-to-background ratios, phantom geometries, and reconstruction protocols. The effect of increasing positron energy was clearly reflected in the FWHM values measured with different isotopes.
Conclusion:
A method has been developed for measuring the spatial resolution that is achieved with clinical PET protocols, providing more relevant estimates than are typically obtained with established procedures. The proposed method requires no special equipment and is versatile, being capable of measuring resolution for different isotopes as well as for different reconstruction protocols. The new technique promises to aid standardization of PET data acquisition by allowing a more informed selection of reconstruction parameters.
Details
- Title: Subtitle
- Measuring PET Spatial Resolution Using a Cylinder Phantom Positioned at an Oblique Angle
- Creators
- Martin A Lodge - Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland; andJeffrey P Leal - Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland; andArman Rahmim - Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland; andJohn J Sunderland - Department of Radiology, University of Iowa, Iowa City, IowaEric C Frey - Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
- Resource Type
- Journal article
- Publication Details
- The Journal of nuclear medicine (1978), Vol.59(11), pp.1768-1775
- Publisher
- Society of Nuclear Medicine
- DOI
- 10.2967/jnumed.118.209593
- PMID
- 29903932
- PMCID
- PMC6225537
- ISSN
- 0161-5505
- eISSN
- 1535-5667
- Language
- English
- Date published
- 11/2018
- Academic Unit
- Radiology; Physics and Astronomy; Radiation Oncology
- Record Identifier
- 9984047766802771
Metrics
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