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

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

“…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].…”

“…Previous published values showed that the presence of 177m Lu and the effect of background when measuring low currents in the ionisation chamber are the components with the highest impact in the uncertainty budged [13,14,19]. The improved uncertainty achieved in this work compared to previous published values is due to a combination of: the negligible amount of 177m Lu present, low background (due to the "back-to-back" formation and the dual lead shield) and the high starting 177 Lu activity.…”

“…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].…”

“…There have been 14 previous publications reporting half-life measurements of 177 Lu [6][7][8][9][10][11][12][13][14][15][16][17][18][19], which are summarised in Table 1. 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. Therefore, for an accurate a e-mail: kelley.ferreira@npl.co.uk half-life determination it would be beneficial that insignificant levels of 177m Lu were present to cause interferences in the measured exponential decay of the 177 Lu activity.…”