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Description
Gallium-68 is a short lived (T1/2 = 67.83 (20) min), positron-emitting radionuclide that is commonly used in the diagnosis of prostate cancer via positron emission tomography (PET), along with other diagnostic techniques. Due to its medical relevance, the accuracy of its half-life is of great importance.
There have been at least 12 determinations of the 68Ga half-life, occurring from 1960 to 2016. However, these determinations continue to result in a discrepant dataset [1]. This discrepancy has resulted in a relative standard uncertainty of 0.29 % on the evaluated half-life. The National Physical Laboratory (NPL) previously determined a half-life value in 1971 using an ionisation chamber, whilst this value agreed with the current half-life it was excluded from the final analysis in Kuzmenko, 2019 [1]. To aid in the resolution of this discrepant dataset and lead to an improvement in the accuracy and precision of the evaluated half-life, the National Physical Laboratory has performed a new half-life campaign and compared results against the previous literature.
Samples containing 68Ga were measured on both of the NPL secondary standard ionisation chambers, along with a high-purity germanium gamma spectrometer, over a period of more than 15 half-lives.
The resulting half-life from the ionisation chamber datasets was determined to be 67.801 (43) min, which is in agreement with the previously derived NPL value from 1971 (67.80 (8) min), along with the current evaluated half-life of 67.83 (20) min.
[1] Kuzmenko, N. K., 2019, Updated decay data evaluation for 68Ga, Appl. Radiat. Isot., 152, 188-192.
