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From Hevesy to PET

From Hevesy to PET. Nuclear Medicine Imaging. Bevezető. Személyes bemutatkozás(video): Név, iskola bemutatása, néhány kép az iskoláról We are interested in nuclear phisics : We join the Twinning project on THE FIRST EUROPEAN NUCLEAR COMPETITION FOR SECONDARY SCHOOL STUDENTS.

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From Hevesy to PET

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  1. From Hevesy to PET Nuclear MedicineImaging

  2. Bevezető • Személyes bemutatkozás(video): • Név, iskola bemutatása, néhány kép az iskoláról • Weareinterested in nuclearphisics: • WejointheTwinning project on THE FIRST EUROPEAN NUCLEAR COMPETITION FOR SECONDARY SCHOOL STUDENTS • A nukleáris medicina megalkotójának tekintik a magyar George Charles de Hevesy-t. Aki 1943-ban Nobel díjat kapott a radioaktív nyomjelzés felfedezésért. • Ennek kapcsán szeretnénk a mai modern diagnosztikai eljárásokról egy rövid bemutatót tartani.

  3. What is Nuclear Medicine? • NUCLEAR MEDICINE IMAGINGprocedures look at the bodily functions to help make your diagnosis.

  4. Radiology and nuclearimagery In traditionalradiology, onemeasurestherelativeabsorption of X-Rayspassingthroughthe body. In nuclearimagery, a handful of radioactiveatoms (carefullychosentolatchontotherelevantorgan) areinjectedintothe body, and the gamma raystheyemitfrominsidearedetectedsoastomeasurethe concentration of radioisotope in theorgan in question.

  5. What about the radiation? • Very small amounts of radiation are given during nuclear medicine imaging scans. • Larger amounts are used for therapy in order to target very specific areas. • The scanners (equipment) do not give off radiation.

  6. Nuclear medicine imaging Nuclear medicine is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear medicine, in a sense, is "radiologydone inside out" or "endoradiology" because it records radiation emitting from within the body rather than radiationthat is generated by external sources like X-rays. In addition, nuclear medicine scans differ from radiology as the emphasis is not on imaging anatomy but the function and for such reason, it is called a physiological imaging modality. Single photon emission computed tomography(SPECT) and positron emission tomography(PET) scans are the two most common imaging modalities in nuclear medicine. Diagnostic In nuclear medicine imaging, radiopharmaceuticals are taken internally, for example, intravenously or orally. Then, external detectors (gamma cameras) capture and form images from the radiation emitted by the radiopharmaceuticals. This process is unlike a diagnostic X-ray, where external radiation is passed through the body to form an image. There are several techniques of diagnostic nuclear medicine.

  7. History

  8. The origins of thismedical idea The origins of thismedical idea date back as far asthe mid-1920s in Freiburg, Germany, when George de Hevesy made experimentswithradionuclidesadministeredtorats, thus displaying metabolicpathways of thesesubstances and establishingthetracerprinciple. Possibly, thegenesisof thismedicalfieldtookplacein 1936, whenJohn Lawrence, knownas"thefather of nuclearmedicine", took a leave of absencefromhisfacultypositionat Yale MedicalSchool, tovisithisbrother Ernest Lawrenceathisnewradiationlaboratory (nowknownastheLawrence Berkeley National Laboratory) in Berkeley, California. Lateron, John Lawrence made thefirstapplicationinpatients of an artificialradionuclidewhen he used phosphorus-32 totreatleukemia. John H. Lawrence

  9. George Charles de Hevesy • George Charles de Hevesy (German: Georg Karl von Hevesy; 1 August 1885 – 5 July 1966) was a Hungarian radiochemistand Nobel Prize in Chemistrylaureate, recognized in 1943 for his key role in the development of radioactive tracers to study chemical processes such as in the metabolism of animals. He also co-discovered the element hafnium.

  10. Introduction to Nuclear Medicine

  11. Nuclear Medicine Diagnoses What?

  12. Nuclear medicine • Nuclear medicine is the medical specialty in which radioactive tracers are used for the diagnosis and treatment of diseases, for example, where patients are scanned in so-called SPECT and PET scanners. • Worldwide, around two million patients are scanned every year using nuclear medicine techniques.

  13. An impossibleproblem In 1912 Rutherford set Hevesy thechallengetoseparateRadium-D from lead. Radium-D is an isotope of lead, that is, it has thechemicalproperties of lead, butwith a differentmass of the most common.  Hevesy’ssimple and ingenious idea wasthattheradioactiveRadium-D, whichcouldnot be separatedfromthe lead, could be detected in the body and thuscould be usedas an indicatorortracerfor lead.

  14. Hevesy discoveredthebasicprinciplesfortheindicatortechnique, whichlaterevolvedintonuclearmedicine Hevesy intendedtousethetechnology of radioactivetracingfortrackingthebiologicalprocedures. However, theheavyradioactiveelementsweren’tsuitableforthatbecausetheyhavenothingtodobiology. Therefore in 1935 he initiatedthemethod of neutron activation, whichhelpedhimtocreate neutron overflow byshooting neutron into a nucleus (creatingnewisotopewithradiation). Forexamplewiththehelp of thereaction he createdradioactivephosphorous. He couldfollowtheway of phosphorous in theorganismtrackingthe radiation of (which had beeninjectedpreviously). Thisway Hevesy becamethecreator of medicalisotopediagnostics.

  15. PositronEmissionTomography Single photon emission computed tomography(SPECT) and positron emission tomography(PET) scans are the two most common imaging modalities in nuclear medicine.

  16. PositronEmissionTomography • The technique is based on the detection of radioactivity emitted after a small amount of a (beta-positiveemitter) radioactive tracer is injected into a peripheral vein. • The tracer is administered as an intravenous injection usually labelled with oxygen-15, fluorine-18, carbon-11, or nitrogen-13. • The total radioactive dose is similar to the dose used in computed tomography.

  17. PositronEmissionTomography

  18. Signaldetector PositronEmissionTomographyis an imagingtechniquewhichmapsthedistribution of beta-positiveemittersthroughoutthe body. The positrons (positiveelectrons) emittedareidentifiedbythefactthat, oncetheyhavelosttheirenergy (theirrangedoesnotexceed a fewmillimeters), theyannihilatewith an electrontoyieldtwo gamma photonseach of 511 keV of energy and emitted back to back. Both gamma reachsimultaneously a pair of opposingdetectorsplacedoneitherside of theannihilationlocation. Electroniccircuitsassociatingthesepairs of detectorsaredesignedtoidentifytheannihilationphotons.

  19. Coincidencecircuit • The two gamma raysemitted back to back duringthepositronannihilationaredetected almost simultaneouslybytwooppositescintillators. • Thiscoincidence is a verystrongsignaturethatdistinguishesthemfromotherphotons. Specificelectroniccircuits "coincidence" circuitspickup gamma pairs. • Onthefigure, it is requestedthatthesignalscomingfromthescintillators A and B coincidewithin 12 billionths of a second (nanosecond). • The straight line joiningthecenters of detectors A and B is an approximation of theactual line of flight of thetwo gamma rays

  20. FDG-PET Forexample: PET scanningwiththetracer fluorine-18 (F-18) fluorodeoxyglucose (FDG), calledFDG-PET, is widelyused in clinicaloncology. Thistracer is a glucoseanalogthat is takenupbyglucose-usingcells and phosphorylatedbyhexokinase (whosemitochondrialform is greatlyelevated in rapidlygrowingmalignanttumors) There are 4 positron-emitting radioisotopes that are usemore than any others. These are • fluorine-18 (F-18), • carbon-11 (C-11), • nitrogen-13 (N-13) and • oxygen-15 (O-15). Thereason these are so commonly used is that they have manyattractive properties, one of which is that they can be easilysubstituted directly into biomolecules.

  21. Average Free Range Positronsemittedby a beta-plus marker disappearaftertravelling a fewmillimetresthroughthe body, byannihilatingwith an atomicelectron in a processwherebybothparticlesceasetoexist.

  22. Tumor is seen • Whole-body PET scan using 18F-FDG. The normal brain and kidneys are labeled, and radioactive urine from breakdown of the FDG is seen in the bladder. In addition, a large metastatic tumor mass from colon cancer is seen in the liver. Animation

  23. Producingbeta-positiveemitterradioisotopes

  24. The Cyclotron and PET • The most difficult and sophisticated part of a PET installation is the cyclotron. It is a machine used to produce the radioisotopes (radioactive chemical elements) which are used to synthesize the radiopharmaceuticals (the actual substances which are used to make the functional images of the body).

  25. Cyclotron The cyclotronwasone of theearliesttypes of particleaccelerators, and is stillusedasthefirststage of somelarge multi-stageparticleaccelerators. Itmakesuse of themagneticforceon a movingchargetobendmovingchargesinto a semicircularpathbetweenaccelerationsby an appliedelectricfield. The appliedelectricfieldaccelerateselectronsbetweenthe "dees" of themagneticfieldregion. The field is reversedatthecyclotronfrequencytoacceleratetheelectrons back acrossthegap. Whenthecyclotronprinciple is usedtoaccelerateelectrons, it has beenhistoricallycalled a betatron.

  26. History Brainchild (idea): Leo SzilardRealization: Ernest Orlando Lawrence • Leo Szilard submitted patent applications for a linear accelerator in 1928, and a cyclotron in 1929. • American physicist Ernest Lawrence received the 1939 Nobel Prize for inventing the cyclotron. Credit went to Lawrence, but Leo Szilard (Hungarian-German-American physicist and inventor) invented it first. • Szilard filed a German patent application on the cyclotron on January 5, 1929. Lawrence conceived the idea independently several months later. Lawrence's American patent application was not filed until January 26, 1932. L. Szilard (1898 - 1964) E. Lawrence (1901 – 1958)

  27. Leo Szilard (left) talks with Ernest O. Lawrence (right) at the American Physical Society meeting in Washington D.C., on April 27, 1935.(http://members.peak.org/~danneng/lawrence.html)

  28. Shorthalf-life •  The most frequently used radioisotopes in PET are: • Carbon-11, with a half-life of 20 min • Nitrogen-13, with a half-life of 10 min • Oxygen-15, with a half-life of 2 min • Fluorine-18, with a half-life of 110 min • be readily incorporated into an useful radiopharmaceutical, by chemical synthesis.

  29. PET Center • This is why most of the PET installations in the world have the cyclotrons just by the side of the PET machine. • It is truly a race against the clock, once the radioactive isotope is produced, to synthesize the radiopharmaceutical and get injected into the patient, so the PET and the cyclotron should be a few minutes away from each other.

  30. Képek készítésének ideje Nukleáris hétvége Debrecenben 2007. november 16-18.

  31. Látogatás a PET centrumban

  32. Hungariancyclotronhistory: Cyclotron of ATOMKI • The MGC-20 cyclotron of ATOMKI has been the major particle accelerator facility in Hungary since it started operation in 1985. • For about two decades it was the only cyclotron type accelerator in the country and was used for various research and application programs. In thebiginning ATOMKI producedbeta-positiveemitterisotopesforClinic of Debrecen.

  33. Medicalcyclotrons Many positron emitters have short half-lives and thus require on-site cyclotrons for application.

  34. PET cyclotron

  35. PET Center in Debrecen PET-CT DIAGNOSZTIKAI és CIKLOTRON KÖZPONT – BUDAPEST PET centrum Debrecen

  36. Source • https://www.nbi.ku.dk/english/www/george_/de_hevesy/del1/ • https://en.wikipedia.org/wiki/Leo_Szilard • https://en.wikipedia.org/wiki/Positron_emission_tomography • https://www.researchgate.net/publication/8605379_PET_tracers_and_radiochemistry • http://www.cerebromente.org.br/n01/pet/petcyclo.htm

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