Experimental determination of some nuclear decay data in the decays of 177 Lu, 186 Re and 124 I

Status of the decay data for medical radionuclides: existing and potential diagnostic γ emitters, diagnostic β+ emitters and therapeutic radioisotopes

Recommended half-lives and specific well-defined emission energies and absolute emission probabilities are important input parameters that should be well-defined to assist in ensuring the diagnostic and therapeutic efficacy of individual radionuclides when applied in the field of nuclear medicine. Bearing in mind the nature of these requirements, approximately one hundred radionuclides have been considered and re-assessed as to whether their decay data are either adequately quantified, or require further in-depth measurements to improve their existing status and merit full re-evaluations of their decay schemes. The primary aim of such a review is to provide sufficient information on the existing and future requirements for such atomic and nuclear data.

60 years of absolute standardization of radionuclides by coincidence counting methods in the Romanian metrology laboratory

This review paper presents the contribution of the Radionuclide Metrology Laboratory (RML) to the development and practical application of the coincidence counting methods. It is also intended to pay tribute to Dr. Enric Leon Grigorescu, the founder of our school of radionuclide metrology. A synthetic treatment of the method, applied to some classes of radionuclides with their common and particular aspects in standardization, is presented: pioneering calculation of instrumental corrections, specific method corrections applied for various types of decay schemes in the variant of efficiency extrapolation, results obtained in international comparisons.

Determination of the half-life and the absolute photon emission intensities for the main gamma-ray energies of 124I

The National Institute of Standards and Technology (NIST) performed new standardization measurements for ¹²⁴I. As part of this work the absolute photon emission intensity for the main gamma-rays of ¹²⁴I were determined using several high-purity germanium (HPGe) detectors. In addition, the half-life for ¹²⁴I was also determined using an HPGe detector. Ionization chamber measurements were performed for additional sources, but it was not possible to obtain a precise half-life value.

Standardization of I-124 by three liquid scintillation-based methods

A solution of ¹²⁴I was standardized for activity by 4πβ(LS)-γ(NaI) live-timed anticoincidence (LTAC) counting, with confirmatory measurements by triple-to-double coincidence ratio (TDCR) and CIEMAT-NIST efficiency tracing (CNET) liquid scintillation counting. The LTAC-based standard was shown to be in agreement (within k = 1 uncertainties) with previous measurements at NIST and elsewhere. Calibration settings for radionuclide calibrators were determined and a discrepancy with literature values, partially due to a calibration methodology dependent upon an erroneous setting for ¹⁸F, was identified and explained.

(177)Lu: DDEP Evaluation of the decay scheme for an emerging radiopharmaceutical

A new decay scheme evaluation using the DDEP methodology for (177)Lu is presented. Recently measured half-life measurements have been incorporated, as well as newly available γ-ray emission probabilities. For the first time, a thorough investigation has been made of the γ-ray multipolarities. The complete data tables and detailed evaluator comments are available through the DDEP website.

Activity standardization, photon emission probabilities and half-life measurements of (177)Lu

Activity standardization of (177)Lu and measurement of two nuclear parameters were done. Activity standardization of (177)Lu was done utilizing the 4πβ-γ coincidence method with a combined standard uncertainty of 0.28%. Emission probability of 112.95keV and 208.37keV was measured by calibrated spectrometer with HPGe detector. The efficiency was computed with MCNP code and validated using experimental points. Half-life was derived from prolonged measurement of peak area by three different spectrometer systems and also from measurement with ionization chamber.