A phantom-based method to standardize dose-calibrators for new β+-emitters

Clément Morgat, Joachim Mazère, Philippe Fernandez, Sébastien Buj, Delphine Vimont, Jürgen Schulz, Frédéric Lamare
Nuclear Medicine Communications. 2015-02-01; 36(2): 201-206
DOI: 10.1097/mnm.0000000000000227

Lire sur PubMed

1. Nucl Med Commun. 2015 Feb;36(2):201-6. doi: 10.1097/MNM.0000000000000227.

A phantom-based method to standardize dose-calibrators for new β+-emitters.

Morgat C(1), Mazère J, Fernandez P, Buj S, Vimont D, Schulz J, Lamare F.

Author information:
(1)aBordeaux University Hospital Center, Nuclear Medicine Department,
Haut-Levêque Hospital bUniversity of Bordeaux, INCIA, UMR 5287 cCNRS, INCIA, UMR
5287, Bordeaux, France.

Quantitative imaging with PET requires accurate measurements of the amount of
radioactivity injected into the patient and the concentration of radioactivity in
a given region. Recently, new positron emitters, such as (124)I, (89)Zr, (82)Rb,
(68)Ga, and (64)Cu, have emerged to promote PET development, but standards are
still largely lacking. Therefore, we propose to validate a simple, robust, and
replicable methodology, not requiring the use of any standards, to accurately
calibrate a dose-calibrator for any β(+)-emitter. On the basis of (18)F
cross-calibration, routinely performed with fluorine-18-fluorodeoxyglucose
(F-FDG) in nuclear medicine departments, a methodology was developed using
β(+)-emitting’ phantoms to cross-calibrate the dose-calibrator for measuring the
activity of positron emitters and quantifying the standardized uptake value
(SUV). Ga phantoms filled with activities measured with various dose-calibrator
settings were imaged to establish calibration curves (SUV values as a function of
the dose-calibrator settings) and to identify the setting value, yielding an SUV
value of 1.00 g/ml, reflecting an accurate measurement of (68)Ga activity.
Activities measured with the identified setting were finally checked with a
γ-counter. The setting of 772±1 was identified as ensuring that the studied
dose-calibrator is correctly calibrated for (68)Ga to ensure an SUV value of
1.00±0.01 g/ml. γ-Ray spectrometry confirmed the accurate measurement of Ga
activities by the dose-calibrator (relative error of 2.9±1.5%). We have developed
a phantom-based method to accurately standardize dose-calibrators for any
β(+)-emitter, without any standards.

DOI: 10.1097/MNM.0000000000000227
PMID: 25321161 [Indexed for MEDLINE]

Auteurs Bordeaux Neurocampus