Introduction to Radiopharmaceutical chemistry (Lecture 1) Outline 1. Introduction Radiopharmaceuticals, Basics on radiochemistry, Molecular imaging, Nuclear medicine, PET and SPECT, Radiopharmacology 2. Radionuclide production, Nuclear reactor, Cyclotron, Radionuclide generators in medicine Radionuclide generators 3. Radiometal pharmaceuticals I Radiopharmaceutical chemistry: 99m Tc-Radiopharmaceuticals, Kits 4. Radiometal pharmaceuticals II Radiopharmaceutical chemistry: Re, Cu, In, Ga, Y 5. Organic radiopharmaceuticals I Introduction to PET, 11 C-radiopharmaceuticals 6. Organic radiopharmaceuticals II 11 C-radiopharmaceuticals (continuation) 7. Organic radiopharmaceuticals III Radiofluorinations: 18 F-radiopharmaceuticals 8. Organic radiopharmaceuticals IV Radiohalogenations: Br, I, At 9. Radiopharmacology Diagnostics & Therapeutics 1
Molecular Imaging Molecular imaging of specific biological and physiological processes at the molecular level in the intact organism Optical imaging Radionuclide-based imaging Making the body biochemically transparent Molecular Imaging Gene expression Protein expression Protein function Physiological function 2
Application of radionuclides in life sciences Universal, efficient, simple igh sensitivity Studies of metabolism Mass balance, in vivo disribution (autoradiography) 14 C, 3, 32 P, 35 S Radiotracer-concept George de evesey 1943 Nobel Prize (Chemistry (Application of radionuclide-based indicators, Father of nuclear medicine) In vivo pharmacology/biochemistry Positron-emission-tomography (PET) Single photon emission computered tomography (SPECT) in vivo radiotracer techniques Molecular probes and the radiotracer principle Biochemical information 3
Radionuclides in medicine Nuclear medicine Nuclear medicine: Diagosis Use of gamma- and positron emitters Sensitivity = right positive/(right positive + false negative) Specificity = right negative/right negative + false positive) Nuklear medicine: Therapy Use of particle emitters (α, β - ) Antibody Iodine- 131 Yttrium-90 Indium-111 Rhenium-186, 188 Tumor cell Antigen Emission tomography - SPECT Gantry-design of a SPECT-camera 4
Emission tomography - PET O O O O 18 F O β + 511 kev BGO or LSO Scintillator crystals β 180 511 kev Photomultiplier Emission tomography - PET 5
Emission tomography - PET Pathobiochemistry in vivo Glycolysis Active transport Neurotransmission Multidrug resistance ypoxia Apoptosis Angiogenesis Monitoring of gene therapy Inflammation, Infection Tumor-associated antigenes and receptors etc. smart radiotracers! 6
Selection criteria and use of molecular probes for nuclear medicine molecular imaging Can an appropriate compound be labeled with a suitable radionuclide? Target specificity igh membrane permeability Rapid blood clearance No or only slow peripheral metabolism igh specific activity (Radiotracer principle) Low non-specific binding (Target-to-Non-target ratio >>1) Only a limited number of transport and biochemical reaction steps to facilitate tracerkinetic modelling 1. Molecular probes based upon enzyme-mediated transformations 2. Molecular probes based upon stochiometrical binding interactions 3. Molecular probes for perfusion studies Opportunities and trends of radiopharmaceutical chemistry Making tumors visible as early as possible Better understanding of tumor biochemistry Therapy monitoring 7
Complex evaluation of tumor biology Number of tumor cells 10 13 10 12 10 10 10 0 Clinical detection Sensitve detection Cure Complex evaluation Tod Number of tumor cells 10 13 10 12 10 10 10 0 Clinical detection Sensitve detection Cure Gene expression? Metabolic activity? Angiogenesis? Tumor-associated binding sites? Apoptosis? ypoxia? 8
Opportunities and trends of radiopharmaceutical chemistry Molecular of neurobiological basis of cerebral function See, how the brain is working Opportunities and trends of radiopharmaceutical chemistry PET in drug development and evaluation Pharmacokinetics (Administration, distribution, elimination) Radiolabeled drug Pharmacodynamics (Drug effect on metabolism, blood flow, receptor occupancy etc.) Radiotracers (probes) + drug 9
RADIOPARMACEUTICAL CEMISTRY Nuclear pharmaceuticals Radiopharmaceuticals Radioactive drug - Diagnostics (Radiotracers) - Therapeutics Lead structure (high-throughput-screening, pathobiochemistry Target molecule Modification: Introduction of radionuclide Biodistribution, pharmacokinetics ( contrast, quantifiable, minimal radiation burden, max. effect in radiation therapy Labeling methods Radiotracer-lead structure Radionuclide production 10
Important terms Radiation and radiation energy β, γ, β +, α Radioaktivity Equation; 1 Ci = 3,7. 10 10 Bq specific activity carrier-free, non-carrier-added, carrier-added alf-life (physical, biological, effective) Energy dose Nuclear reactions Nuclear reactor, Cyclotron Cross-section Activation equation (n,γ), (p,n), (p,α) and (d,n)-reactions Radiopharmaceutical chemistry Radiolabeling, radiotracer, lead structure radiochemical purity Good Manufacturing Practice (GMP) Radiopharmacology, Nuclear medicine Dose, Target/Nontarget, Sensitivity and specificity SPET, PET, in vitro, in vivo, Perfusion, clearance, Pharmacokinetics, Pharmacodynamics RADIOCEMISTRY Nuclear reactions Radionuclide production Radioaktive radiation Labeling methods Production of radiopharmaceuticals 11
RADIOCEMISTY Radionuclide production Nuclear reactionr Cyclotron Processing hot labs Radionuclide production Table of nuclide 12
Radionuclide production - Radioactivity Bq 10 15-10 18 10 14 Czernobyl accident I-131, Xe-133, Cs-137, Kr-85, Sr-90 u.a. Spallation I-131, I-133/Xe-133, Mo-99/Tc-99m, Xe-135 u.a. 10 9 Thyroid ectomy 10 3 10 1 K-40in adults Cs-137/l milk in Berlin after Czernobyl Radionuclide production Impurities with dramatic effects Radiation burden e.g. 125 I in 123 I, euthyreotic thyroid 533 mgy/mbq 125 I 5.6 mgy/mbq 123 I 1% of 125 I doubles radiation burden!!! 13
Radionuclide production Nuclear power plants Iod-131 era Iod-123 (13 h) Shorter physical half-lifes in the clinics Technetium-99m era PET era 11 C 20.4 min 14 N(p,α) 11 C 13 N 10.0 min 16 O(p,α) 13 N 15 O 2.0 min 14 N(d,n) 15 O 18 F 109.6 min 20 Ne(d,α) 18 F 18 O(p,n) 18 F Radionuclides Diagnosis Iodine-123 Technetium-99m PET-Radionuclides Therapy Iodine-131 Radiometals (hard M 3+ ) C-11 F-18 I-123 Tc-99m authentic F for, O I for, O, C 3 dramatic alterations compound Increasing availability of radionuclides 14
TcO 4 - Iodide Active transport 10-8 - 10-9 M Iodide 10-1 M Chloride hnis (mamma CA): TcO 4- Uptake D.. Moon et al., Nucl. Med. Biol. 28 (2001) 829-834 15
PET: Radiopharmaceuticals [ 18 F]FDG O besonders in irn und erz O O O 18 F O O C 2 O O O O O gute Permeabilität O O C 2 O O O exokinase Phosphatase 18 F-DG 18 F-DG 18 F-DG-6- P Plasma O Zelle O C 2 O O F O E in allen Organen, aber weniger in irn und erz D-Glucose 2-Desoxy-D-glucose 2-Fluor-2-desoxy-D-glucose Principle: Increased glycolysis in tumor cells (O. WARBURG) Glucose transporter (GLUT 1) and/or hexokinase Intracellular phosphorylation through hexokinase Intracellular trapping PET: Radiopharmaceuticals [ 18 F]FDG 18 F-FDG PET - Control Nuklearmedizin TU Dresden / PET-Zentrum Rossendorf 16
PET: Radiopharmaceuticals [ 18 F]FDG Primary tumour in the neck with lung metastesis R L R L R L Nuklearmedizin TU Dresden / PET-Zentrum Rossendorf PET: Radiopharmaceuticals [ 18 F]FDG Therapy control Morbus odgkin Lymphoma (before Chemotherapy) Nuklearmedizin TU Dresden / PET-Zentrum Rossendorf 17
PET: Radiopharmaceuticals [ 18 F]FDG Therapy control Morbus odgkin Lymphoma (after Chemotherapy) Nuklearmedizin TU Dresden / PET-Zentrum Rossendorf Radiopharmaceuticals: 3-O-Methyl-[ 18 F]FDOPA Amino acid transporter Blood-brain-barrier Tumour MeO O 2 N 18 F CO 2 activity (Bq/ccm ) 25000 20000 15000 10000 5000 Tumour Reference region Tumour / Brain 2.2 4 3,5 3 2,5 2 1,5 1 0,5 tumour / non tumour 0 0 0 1000 2000 3000 4000 5000 Frame Midpoint Time [sec] MRT: Surgery defect Target/Non-Target OMFD-PET 18
PET: Radiopharmaceuticals - [ 18 F]FDOPA O 2 C O O 2 C Decarboxylation O O N 2 O N 2 O N 2 Tyrosine Dopa Dopamine 2 N CO 2 O O 18 F Control Decarboxylation disturbance Dopa to dopamine PET: Radiopharmaceuticals - [ 18 F]Fluoride O O P O O O O P O O O O P O O Ca 2+ Ca 2+ Ca 2+ PO 3- Ca 2+ 4 O - Ca 2+ PO 3- Ca 2+ 4 F - O - Ca 2+ Knochenmetastase Nuklearmedizin TU Dresden / PET-Zentrum Rossendorf 19
PET: Radiopharmaceuticals - [ 11 C]Acetats Precise mechanism unclear Increased lipid metabolism O * ONa Lymph nodemetastasis Rezidive Nuklearmedizin TU Dresden / PET-Zentrum Rossendorf 20
Strahlenschutz Gesamte Strahlenexposition 5-A-Regel Radiation protection Begrenzung der eingesetzten Aktivität Aufenthaltszeit begrenzen - Verringerung der Bestrahlungszeit Abstand halten Abschirmungen verwenden Aufnahme von radioaktiven Stoffen vermeiden (bei Umgang mit offenen Radionukliden) Kombination von Strahlenschutzmaßnahmen 1. Verringerung der Bestrahlungszeit Aufenthaltszeit begrenzen 2. Abstand halten 3. Abschirmungen verwenden 21