Radiochemistry of Technetium-99m Otto C. Boerman, PhD

Transcription

1 Radiochemistry of Technetium-99m Otto C. Boerman, PhD Radboud University Nijmegen Medical Center, The Netherlands

2 Radboud University Nijmegen Medical Center, The Netherlands

3 Radboud University Nijmegen Medical Center, The Netherlands

4 Radboud University Nijmegen Medical Center, The Netherlands

5 Technetium : Dimitri Mendeleev: Em : Ilmenium, Pelopium, Davyum, Nipponium : Noddack et al.: Masurium : Perrier & Segre: Panormium, τεχνητοζ - Oxidation state: 0, 1+, 2+, 4+, 5+, 6+, : Kenna & Kuroda - pitchblende Congo: 0.2 ng/kg 5

6 Technetium-99m 99m Tc is ametastable t state t of technetium-99 ti ( 99 T) Tc) with a half-life of 6.02 hours. decay to the ground state of 99 Tc: 90% emission of gamma photons of 140 kev Mo-99 Tc-99m Tc-99 6

7 Radiation exposure from Tc-99m The specific gamma ray constant for Tc-99m is 2 mgy / hour.mbq at 1 cm The half-value layer is 0.17 mm lead Control of the radiation exposure: reduction factor mm Pb

8 Production of Technetium-99m 8

9 Development of Tc-99m generator at BNL Powell "Jim" Richards and Walter Tucker 9

10 Tc-99m generator - Technetium 99m ( 99m Tc) is a decay product of molybdenum-99 (t½ = 66 h) - Obtained by eluting it from a molybdenum-99 generator 10

11 Labeling halfproducts with Tc-99m Reduction of TcO 4 - Reductor: Sn 2+, Fe 2+ TcO 4 - Incubation with halfproduct Quality control Radionuclidic purity: breakthrough of Mo kev photons, 0.5 cm lead, dose calibrator TcO 2 ITLC: stationary phase silicagel mobile phase 0.1 M ammonium acetate, ph 5.5

12 Coordination chemistry of Tc-99m TcO 4 - Sn 2+ Tc(V) Square pyrimidal complex Gluconate glucoheptonate 12

13 Tc-99m-labeled agents for myocardial perfusion 99m Tc-sestamibi 13

14 Tc-99m-labeled agents for cerebral perfusion 14

15 Tc-99m-labeled agents for renal function 15

16 Tc-99m-demotate 16

17 Tc-99m-Methylene diphosphonate (MDP) 17

18 Labeling antibodies, peptides and small molecules with Tc-99m Direct labeling method: Using free sulfhydril groups of the biomolecule to chelate Tc-99m (Schwarz method, iminothiolane method) Bifunctional chelate method: Modification of biomolecule with bifunctional chelating agent (HYNIC, MAG 3, tetraamine, a.o.) Hybrid method: Incorporating tripeptide sequence (Gly 3, Cys-Gly-Gly, Cys-Gly-Cys) to introduce a N 4, N 3 S, N 2 S 2 donor set 18

19 Schwarz method: a direct labeling method Incubate Ab with β-me (1000:1) 30 min, RT Purify Ab by Gelfiltration Add transchelator (gluconate, MDP, tricine) Add TcO 4 - Incubate 10 min, RT QC with ITLC Mather & Ellison. J Nucl Med 1990; 31:

20 Iminothiolane method: a direct labeling method protein protein Patricio et al. Q J Nucl Med 1995; 39:

21 Tc-99m labeling via a bifunctional chelate: S-MAG3 H 2 N-peptide M NaHCO 3 ph 8.5 peptide-nh TcO 4 - RT Tricine/tartrate 99 Tc Hnatowich et al. J Nucl Med. 1998; 39: peptide-n NH H 21

22 Tc-99m labeling via a bifunctional chelate: S-HYNIC H 2 N-peptide + peptide-nh TcO 4 - SnCl 2 Coligand L peptide

23 Tc-99m-Interleukin-8 Interleukin-8

24 Tc-99m-Interleukin-8 Interleukin-8 1 min 1 h 2 h 4 h 8 h

25 Tc-99m labeling via HYNIC using different coligands Rennen et al. Bioconj Chem. 2002; 13:

26 99m Tc-IL-8: Effect of the coligand Tricine EDDA TPPTS Nicotinic Isonicotinic Abscess/background ratio:

27 The coordination of Tc-99m in HYNIC-conjugates King et al. Dalton Trans. 2007; 43:

28 Tc-99m labeling using the hybrid method P483: Ac-Lys-Lys-Lys-Lys-Lys-Cys-Gly-Cys-Gly-Gly-Pro-Leu-Tyr-Lys-Lys-Ile-Ile-Lys-Lys-Leu-Leu-Glu-Ser Incubate peptide with TcO 4- glucoheptonate 0.9% NaCl, 20 min, 95 CC 28

29 Tc-99m labeling using the hybrid method P829: cyclo-(n-me)phe-tyr-d-trp-lys-val-hcy(ch 2 CO-β-Dap)-Lys-Cys-Lys-NH 2 Incubate peptide with TcO 4- glucoheptonate 0.9% NaCl, 20 min, RT 29

30 Tc-99m labeling using the tricarbonyl method Formation of Tc(CO) 3 (H 2 O) 3 complex Labeling of (modified) peptide with the Tc(CO) 3 (H 2 O) 3 complex - Alberto, Schibli, Egli, Schubiger. PSI Villigen, ETH Zurich 30

31 Waibel et al. Nat Biotechnol ;17:

32 Tc-99m labeling using the tricarbonyl method Synthesis of 99m Tc(CO) 3 (H 2 O) 3 + Reduce TcO 4- with NaBH 4 and CO (1 atm), 30 min at 75 C or using with Isolink kit: K 2 [H 3 BCO 2 ], 30 min at 100 C 32

33 Tc-99m labeling using the tricarbonyl method 33

34 Tc-99m labeling using the tricarbonyl method Label (modified) peptide with Tc(CO) 3 (H 2 O) 3 + at 2 mg/ml Mix 1 : 2 with 0.5 M MES, ph 6.2 Add 99m Tc(CO) (H O) + Add 99m Tc(CO) 3 (H 2 O) 3 Incubate min at 37 C Labeling efficiency: % Purify the labeled peptide 34

35 99m Tc-IL-8 8inrabbits with im i.m. EColiinfection E.Coli infection 99m Tc-HYNIC-IL-8 99m Tc(CO) 3 -IL-8