Technical Note: Fully‐automated analysis of Jaszczak phantom measurements as part of routine SPECT quality control

Purpose Inspection and quantitative validation of tomographic imaging properties of SPECT systems, i.e., spatial resolution, contrast, and inhomogeneity must be performed in regular intervals. Typically, the modular Jaszczak phantom is used for that purpose, as it offers the possibility to investiga...

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Bibliographic Details
Published in:Medical physics (Lancaster) 2017-05, Vol.44 (5), p.1638-1645
Main Authors: Hirtl, Albert, Bergmann, Helmar, Knäusl, Barbara, Beyer, Thomas, Figl, Michael, Hummel, Johann
Format: Article
Language:English
Subjects:
Humans
Jaszczak phantom
Monte Carlo Method
Phantoms, Imaging
quality assurance
Quality Control
Software
SPECT
Tomography, Emission-Computed, Single-Photon
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Summary:Purpose Inspection and quantitative validation of tomographic imaging properties of SPECT systems, i.e., spatial resolution, contrast, and inhomogeneity must be performed in regular intervals. Typically, the modular Jaszczak phantom is used for that purpose, as it offers the possibility to investigate all three system properties with a single measurement. The interpretation of the measurement is performed visually, thus, being insensitive to subtle changes in system performance. To overcome this limitation, a fully‐automated software for the objective analysis of Jaszczak phantom measurements is proposed here. Methods The software was developed as an ImageJ plugin and offers a number of sequential evaluation steps: automatic determination of the type of Jaszczak phantom, calculation of sector and sphere contrast, detection of ring artifacts using either the Hough transform, followed by a threshold‐based decision criterion, or Student's t‐test. Monte Carlo simulations were used to estimate the detectability limits for ring artifacts. Results The software successfully calculated sector and sphere contrasts and reliably determined ring artifacts present in the homogeneity part of the Jaszczak phantom, based on automatic identification of the phantom type. Conclusion Given the quantitative nature of the produced output, results from one imaging system can easily be compared to another in an objective way. The advantage of the software is clearly that the information provided is objective and does not rely on the experience level of the user.
ISSN:0094-2405
2473-4209
DOI:10.1002/mp.12150