Aspects of yield and specific activity of (n,γ) produced 177Lu used in targeted radionuclide therapy

Production of 177Lu for Targeted Radionuclide Therapy: Available Options

“…Irradiation longer than the 't max ' leads to some loss of activity, but also to an increased 177 Lu/ 176 Lu ratio and hence increased specific activity due to burn-up of 176 Lu. This theoretical analysis justifies the 21-day irradiation cycle used for 177 Lu production in the Dhruva reactor in India [54,55]. The Indian experience has demonstrated that the theoretically calculated value of the actual or available specific activity of 177 Lu after 21 days of continuous irradiation of an enriched Lu target (82 % 176 Lu) at a thermal neutron flux of 1.2×10 14 n.cm -2 .s -1 (1,142 GBq/mg, using k=2.5) is close to the practically obtained value (1,108±24 GBq/mg) [54,55] .…”

“…It has been reported that it is possible to achieve specific activities of 1, 850−2,405 GBq/mg (50−65 Ci/mg) by irradiation in higher flux reactors such as the HIFR reactor at Oak Ridge National Laboratory [56,57]. Lutetium-177 with specific activity values of>740−1,110 GBq (20-30 Ci)/mg could be produced using an enriched 176 Lu target up to approximately 60-80 % in medium flux reactors [54,55] . The SA values are adequate for all established applications of 177 Lu for radionuclide therapy.…”

Synthesis and Preclinical Evaluation of177Lu-CHX-A”-DTPA-Rituximab as a Radioimmunotherapeutic Agent for Non-Hodgkin's Lymphoma

“…7,8 In addition, the high-energy gamma photons emitted by 131 I contribute to the dose burden. 7 While the high neutron absorption cross-section of 176 Lu (2100 b) enables the production of large quantities of 177 Lu in high specific activities in the nuclear reactor, [9][10][11] availability of 90 Y requires the setting up of a 90 Sr/ 90 Y generator or its import from few commercial suppliers which results in increased cost of procurement. 12 In addition, the emission of low-energy and low-abundance c radiations by 177 Lu enables scintigraphic imaging for ascertaining response after therapy as well as for dosimetric assessment, which is not feasible in case of 90 Y due to the absence of gamma emissions.…”

Single vial kit formulation of DOTATATE for preparation of177Lu-labeled therapeutic radiopharmaceutical at hospital radiopharmacy

“…Accordingly, assessing the potential of direct production route based on neutron irradiation of isotopically enriched 176 Lu targets [ 176 Lu(n,γ) 177 Lu] seemed to be an interesting proposition as this is the least intricate and economical way to obtain 177 Lu of acceptable specific activity with negligible generation of radioactive waste. The scope of accessing 177 Lu through 176 Lu (n, γ) 177 Lu route is enticing because of the following two reasons: (i) 176 Lu has very high thermal neutron capture cross section ( σ = 2090 b, I 0 = 1087 b) for formation of 177 Lu and (ii) neutron capture cross section of 176 Lu does not follow 1/v law, and there is a strong resonance very close to the thermal region . With a view to produce 177 Lu of acceptable specific activity through 176 Lu (n,γ) 177 Lu production route amenable for PRRT using Dhruva reactor of our institute, our efforts were intensified in terms of careful optimization of the target irradiation conditions, setting up of shielded facilities equipped with features for handling neutron irradiated target, target processing equipment and assessment of quality of 177 Lu.…”

“…With a view to produce 177 Lu of acceptable specific activity through 176 Lu (n,γ) 177 Lu production route amenable for PRRT using Dhruva reactor of our institute, our efforts were intensified in terms of careful optimization of the target irradiation conditions, setting up of shielded facilities equipped with features for handling neutron irradiated target, target processing equipment and assessment of quality of 177 Lu. The important details of the process have been elaborated in our paper reported earlier …”