Speaker
Description
The short-lived (T1/2 = 26.801(2) h) beta- - emitting radionuclide has been investigated for a wide range of therapeutic medical applications over the past several decades (c.f., Klaassen et al 2019). The safe and effective use of these types of radionuclides for therapy requires accurate dose assessments, which in turn require the most accurate nuclear decay data as input to the calculations. The most recent evaluations of the nuclear and atomic data or 166Ho were performed by the Decay Data Evaluation Project (DDEP) in 2004 (Bé et al. 2005) and by the Evaluated Nuclear Structure Data File (ENSDF) in 2008 (Baglin 2008). Since that time, however, several new measurements of the photon emission rates and decay half-life have been made, many of which were prompted by the EURAMET MetroMRT (Bobin et al. 2019) with the express goal of improving the decay data necessary for dosimetry calculations.
This paper presents the results of a new decay data evaluation of 166Ho that includes 5 new sets of measurements of photon emission rates and the half-life and updates the atomic and beta decay data based on these results and using the latest available calculational models. The result is a more robust recommended half-life value of 26.801(2) h and more precise emission probability values for the 17 gamma rays observed in the decay scheme. Comparisons with previously recommended values are provided, as are suggestions for future measurements.
References
Klaassen, N.J.M., Arntz, M.J., Gil Arranja, A., Roosen, J., and Nijsen, J.F.W., “The various therapeutic applications of the medical isotope holmium-166: a narrative review”, Eur. J. Nucl. Med. Molecul. Imaging Radiopharmacy and Chemistry, (2019). https://doi.org/10.1186/s41181-019-0066-3
Bé M.-M., Chisté V., Dulieu C., Browne E., Chechev V., Kuzmenko N., Helmer R., Nichols A., Schönfeld E., Dersch R., “Table of Radionuclides Volume 2 - A = 151 to 242”, BIPM Monographie 5 – Volume 2, https://www.bipm.org/documents/20126/53814638/Monographie+BIPM-5+-+Volume+2+%282004%29.pdf/047c963d-1f83-ab5b-7983-744d9f48848a?version=1.3&t=1617184334160&download=true (2005).
Baglin, C., Nuclear Data Sheets, 109, 1103 (2008).
Bobin, C., Bouchard, J., Chisté, V., Collins, S.M., Dryák, P., Fenwick, A., Keightley, J., Lépy, M.-C., Lourenço, V., Robinson, A.P., Sochorová, J., Šolc, J., and Thiam, C., “Activity measurements and determination of nuclear decay data of 166Ho in the MRTDosimetry project”, Appl. Radiat. Isot., 153 (2019). https://doi.org/10.1016/j.apradiso.2019.108826
