A phantom study: Should124I-mIBG PET/CT replace123I-mIBG SPECT/CT?

Casper Beijst, Bart de Keizer, Marnix G.E.H. Lam, Geert O. Janssens, Godelieve A.M. Tytgat, Hugo W.A.M. de Jong

Onderzoeksoutput: Bijdrage aan tijdschriftArtikelpeer review

19 Citaten (Scopus)


Purpose: The isotope123I is commonly labeled with meta-iodobenzylguanidine (mIBG) for imaging of neuroendocrine tumors, such as pheochromocytomas and neuroblastomas.123I-mIBG SPECT/CT imaging is performed for staging, follow-up and selection of patients for treatment with131I mIBG. As an alternative to123I,124I-mIBG PET/CT may be used, potentially taking advantage of the superior PET image quality. The purpose of this study was to investigate whether124I PET/ CT improves image quality as compared with123I SPECT/CT for equal patient effective radiation dose (in mSv). Methods: Phantom measurements were performed using the NEMA-2007 image quality phantom. SPECT and PET reconstruction settings were used with and without time-of-flight (TOF) and point-spread-function (PSF) modeling. As a measure of image quality, the contrast-to-noise ratio (CNR) was calculated. The ratio of the123Ito124I activity concentration was determined at which the contrast-to-noise ratio was equal for both modalities. This metric was defined as the contrast equivalent activity ratio (CEAR). Results: CEARs of 47.7, 25.6, 23.1, 14.6, 10.0, and 9.1 were obtained for a TOF and PSF modeled124I reconstruction method and an attenuation and scatter-corrected123I reconstruction method for sphere sizes of 10 to 37 mm, respectively. As the effective radiation dose of124I-mIBG is higher than of123I-mIBG (in mSv/MBq), an equal effective dose corresponds to a CEAR of 5 to 10. Therefore, CEARs higher than 5 to 10 indicate that124I PET/CT outperforms123I SPECT/CT in the sense of image quality for equal patient effective radiation dose. Conclusion: The CEAR is much larger than a factor of 5 to 10 (needed for equal patient effective radiation dose) for most of the reconstruction methods and sphere sizes. Therefore,124I-mIBG PET/ CT is expected to improve image quality and/or may be used to reduce effective patient dose as compared with123I-mIBG SPECT/CT.

Originele taal-2Engels
Pagina's (van-tot)1624-1631
Aantal pagina's8
TijdschriftMedical Physics
Nummer van het tijdschrift5
StatusGepubliceerd - mei 2017


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