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

Half-life measurement of the medical radioisotope 177Lu produced from the 176Yb(n,γ) reaction

“…Previous publications highlighted the issues of using 177 Lu from the 176 Lu(n,γ ) 177 Lu reaction, due to the production of the long lived impurity 177m Lu [14,19,20]. Several authors have reported the activity ratio between the activity of 177m Lu and the activity of 177 Lu in solution: A( 177m Lu)/A( 177 Lu)= 0.007% [11] A( 177m Lu)/A( 177 Lu)= 0.031% [15], A( 177m Lu)/A( 177 Lu)= 0.035% [17] and A( 177m Lu)/A( 177 Lu)= 0.02% [19].…”

“…It was found to be in agreement with the recommended value of 6.6463 (15) days (z-score = 1.8). [20].…”

“…Of these only the measurement reported by Dryak et al [18] has used 177 Lu from production method 2) and therefore not required corrections for the 177m Lu impurity. In a recent evaluation, Kellett [20] identified that the presence of 177m Lu has had a significant influence on the half-life determinations, while Pommé et al [14] observed that the omission of the impurity subtraction led to a 0.5% error in their determined halflife after only 7.6 days in their measurement campaign. A recent investigation at IFIN-HH [19] has highlighted the difficulty in determining an accurate activity ratio between the 177 Lu and 177m Lu.…”