TY  - JOUR
A1  - Werner, Rudolf A.
A1  - Sayehli, Cyrus
A1  - Hänscheid, Heribert
A1  - Higuchi, Takahiro
A1  - Serfling, Sebastian E.
A1  - Fassnacht, Martin
A1  - Goebeler, Maria-Elisabeth
A1  - Buck, Andreas K.
A1  - Kroiss, Matthias
T1  - Successful combination of selpercatinib and radioiodine after pretherapeutic dose estimation in RET-altered thyroid carcinoma
JF  - European Journal of Nuclear Medicine and Molecular Imaging
N2  - No abstract available.
KW  - papillary thyroid carcinoma (PTC)
KW  - selpercatinib
KW  - radioiodine
KW  - combination
KW  - thyroid carcinoma (TC)
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324435
VL  - 50
IS  - 6
ER  - 
TY  - JOUR
A1  - Tran-Gia, Johannes
A1  - Denis-Bacelar, Ana M.
A1  - Ferreira, Kelley M.
A1  - Robinson, Andrew P.
A1  - Bobin, Christophe
A1  - Bonney, Lara M.
A1  - Calvert, Nicholas
A1  - Collins, Sean M.
A1  - Fenwick, Andrew J.
A1  - Finocchiaro, Domenico
A1  - Fioroni, Federica
A1  - Giannopoulou, Katerina
A1  - Grassi, Elisa
A1  - Heetun, Warda
A1  - Jewitt, Stephanie J.
A1  - Kotzasarlidou, Maria
A1  - Ljungberg, Michael
A1  - Lourenço, Valérie
A1  - McGowan, Daniel R.
A1  - Mewburn-Crook, Jamie
A1  - Sabot, Benoit
A1  - Scuffham, James
A1  - Sjögreen Gleisner, Katarina
A1  - Solc, Jaroslav
A1  - Thiam, Cheick
A1  - Tipping, Jill
A1  - Wevrett, Jill
A1  - Lassmann, Michael
T1  - On the use of solid 133Ba sources as surrogate for liquid 131I in SPECT/CT calibration: a European multi-centre evaluation
JF  - EJNMMI Physics
N2  - Introduction
Commissioning, calibration, and quality control procedures for nuclear medicine imaging systems are typically performed using hollow containers filled with radionuclide solutions. This leads to multiple sources of uncertainty, many of which can be overcome by using traceable, sealed, long-lived surrogate sources containing a radionuclide of comparable energies and emission probabilities. This study presents the results of a quantitative SPECT/CT imaging comparison exercise performed within the MRTDosimetry consortium to assess the feasibility of using 133Ba as a surrogate for 131I imaging.

Materials and methods
Two sets of four traceable 133Ba sources were produced at two National Metrology Institutes and encapsulated in 3D-printed cylinders (volume range 1.68–107.4 mL). Corresponding hollow cylinders to be filled with liquid 131I and a mounting baseplate for repeatable positioning within a Jaszczak phantom were also produced. A quantitative SPECT/CT imaging comparison exercise was conducted between seven members of the consortium (eight SPECT/CT systems from two major vendors) based on a standardised protocol. Each site had to perform three measurements with the two sets of 133Ba sources and liquid 131I.

Results
As anticipated, the 131I pseudo-image calibration factors (cps/MBq) were higher than those for 133Ba for all reconstructions and systems. A site-specific cross-calibration reduced the performance differences between both radionuclides with respect to a cross-calibration based on the ratio of emission probabilities from a median of 12–1.5%. The site-specific cross-calibration method also showed agreement between 133Ba and 131I for all cylinder volumes, which highlights the potential use of 133Ba sources to calculate recovery coefficients for partial volume correction.

Conclusion
This comparison exercise demonstrated that traceable solid 133Ba sources can be used as surrogate for liquid 131I imaging. The use of solid surrogate sources could solve the radiation protection problem inherent in the preparation of phantoms with 131I liquid activity solutions as well as reduce the measurement uncertainties in the activity. This is particularly relevant for stability measurements, which have to be carried out at regular intervals.
KW  - 133Ba
KW  - Barium-133
KW  - 131I
KW  - radioiodine
KW  - solid surrogate source
KW  - quantitative SPECT/CT
KW  - comparison exercise
KW  - multi-centre
KW  - calibration
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357740
VL  - 10
ER  -