Sources de rayonnement

Présentation au sujet: "Sources de rayonnement"— Transcription de la présentation:

1 Sources de rayonnement
Aperçu - Utilisation des rayonnements ionisants et des radionucléides dans l'industrie, la médecine, l'agriculture, le contrôle de l'environnement et de l'éducation Jour 5 - Présentations 1 et 2

2 Objectif Discuter des nombreuses applications des sources radioactives dans: Médecine Industrie Produits de consommation Agriculture Recherche, Formation et Éducation

3 Utilisation des rayonnements et des sources radioactives
Les rayonnements et les sources radioactives sont utilisées dans une grande variété de pratiques industrielles, médicales, agricoles et de recherche. Les sources peuvent être utilisées dans des endroits fixes ou peuvent être mobiles.

4 Médical Médecine Diagnostique Radiographie Radioscopie Mammographie
Radiologie interventionnelle CT Scan Radiographie dentaire

5 Médical Therapy thérapie Superficiel Orthovoltage Téléthérapie Co-60
Téléthérapie LINAC Curiethérapie Curiethérapie - après chargement Cs-137, Ir-192

6 Médical Médecine nucléaire Diagnostic: Tc-99m Thérapie : I-131

7 Industrial Industrie Radiographie industrielle Jauges
Contrôle Non Destructif des réservoirs, bateaux etc Jauges Niveau, densité, humidité, débit, etc Utilisé dans industrie des pâtes et des papiers, usine de ciment, les mines d'or, les mines de charbon, l'industrie textile, usine boissons etc Diagraphie  de puits Exploration pétrolière et gazière, les mines de charbon

8 Industrial INDUSTRIE Radiographie industrielle: Ir-192, Co-60, Se-75, Rayon X, Unité de Crawler (Rayon X /Ir Co-60 et Cs-137 pour contrôleur) Diagraphie de puits: Am-241-Be, Cs-137, Co-60, Th-232, Traceur : Kr-85, Ir-192 Jauges : Cs-137, Co-60, Sr-90, Kr-85, Pm-147, Ra-226, Cf-252, Cm-244, Am-241 Analyse : X-ray, Fe-55, Cd-109

9 Agriculture et éducation
Engrais Lutte contre les insectes Conservation des aliments Variabilité génétique Ressources en eau Recherche, Formation et Education Recherche dans les installations nucléaires, les universités et les laboratoires

10 MEDICAL

11 Applications médicales des rayonnements
Radiologie diagnostique Médecine nucléaire Medical use of radiation is typically divided into three areas. Radiothérapie

12 Utilisation des sources de rayonnements en radiodiagnostic
Radiographie standard: statique Radioscopie: dynamique Angiographie: produit de contraste Tomodensitométrie Applications spécifiques: Mammographie: détection du cancer du sein Radiologie pédiatrique: de la naissance à adulte Aide à d'autres spécialités: radiologie interventionnelle Radiologie dentaire

13 Machine à rayons X pour la radiographie et la radioscopie

14 Equipement C-bras Souvent utilisé comme unité «mobile»
Unités de soins intensifs Dans l'examen dans chambre Unités modernes permettent radioscopie + radiographie Capacité de manœuvre c-bras autour du patient sans le déplacer

15 Dentaire (diagnostique)

16 Mammographie et tomodensitométrie

17 Radiothérapie par faisceau externe sources de rayonnement
Kilo Voltage rayon X Traitement superficie : 100 – 150 KVp Traitement profond par rayon X : 150 – 400 KVp Rayons gamma (unités Télecurie) Unité 137Cs (non populaire) : 662 KeV Unité 60 Co :1.25 MeV (Avg) Rayons X & Électrons de Haute énergie Accélérateur linéaire 4-21 MV Various photon energies are used depending on the depth and site of the lesion. Superficial therapy units which operate at 100 to 150kVp are used for treatment to skin lesions mainly. Deep X -ray therapy units operating at 150 to 400 kVp were used to treat deep seated tumours before Gamma rays and High energy X rays were brought in use. 137Cs source was used in External beam units mainly to treat head and neck cases, but this was not popular because of its low energy and low specific activity. High energy X rays produced with particle accelerators such as Betatron and Linear accelerator are used for treating deep seated tumours. It is possible to get different energies from accelerators starting 4 MV to 21 MV or even more. Moreover accelerators can provide electron beams too which have short and specific range in tissue depending on energy.

18 Radiothérapie superficielle
20 à 150 kVp - qualités en rayons X (énergies) semblable au diagnostique Pénétration minimale et limitée à des lésions de la peau traitée avec un faisceau unique Utilisé généralement pour des traitements jusqu'à 5 mm de profondeur. Généralement de petites tailles Applicateurs nécessaires pour collimater le faisceau de la peau du patient This slide may be used to explain the superficial therapy. This is mainly to treat skin lesions where the depth of treatment is about 5mm. X rays with energy 50kVp to 120kVp are generally used. The x ray source is similar to the diagnostic type of x-ray source. But in this case the x-ray beam is ON for longer duration to deliver the dose compared to diagnostic x-ray which is ON only for a fraction of a second.

19 Radiothérapie profonde aux rayons X (Orthovoltage)
Utilise des tubes à rayons X classique Plage de l'énergie kV en Rayons X Utilisé principalement autour kVp Profondeur de traitement environ 20 mm Applicateurs sont utilisés dans le traitement superficiel Tube à rayons X In order to reach deep seated tumours higher energy x-rays of kVp were used. As it could reach deeper tissue than superficial x-rays were termed deep x-ray therapy. The usual depth of treatment with this is about 20 mm. Applicators / cones are used in this type of treatment also. Applicateur

20 Administration de la dose
99mTc ou autres 131I Radiopharmaceuticals can be used for diagnosis or treatment For some medical conditions, it is useful to destroy or weaken malfunctioning cells using radiation. The radioisotope that generates the radiation can be localised in the required organ in the same way it is used for diagnosis ‑ through a radioactive element following its usual biological path, or through the element being attached to a suitable biological compound. In most cases, it is beta radiation which causes the destruction of the damaged cells. This is radiotherapy. Short‑range radiotherapy is known as brachytherapy. Although radiotherapy is less common than diagnostic use of radioactive material in medicine, it has nevertheless become widespread and important. Iodine‑131 and phosphorus‑32 are examples of two radioisotopes used for therapy. Iodine‑131 is used to treat the thyroid for cancers (probably the most successful kind of cancer treatment) and other abnormal conditions such as hyperthyroidism (over‑active thyroid). In a disease called Polycythemia vera, an excess of red blood cells is produced in the bone marrow. Phosphorus‑32 is used to control this excess. A new and still experimental procedure uses boron‑10 which concentrates in the tumor. The patient is then irradiated with neutrons which are strongly absorbed by the boron, to produce high‑energy alpha particles which kill the cancer. This requires the patient to be brought to a nuclear reactor, rather than the radioisotopes being taken to the patient. A new field is targeted alpha therapy (TAT), especially for the control of dispersed cancers. The short range of very energetic alpha emissions in tissue means that a large fraction of that radiative energy goes into the targeted cancer cells, once a carrier has taken the alpha‑emitting radionuclide to exactly the right place. Laboratory studies are encouraging and clinical trials for leukaemia, cystic glioma and melanoma are under way. For targeted alpha therapy (TAT), actinium‑225 is readily available now, from which the daughter Bi‑213 can be obtained to label targeting molecules. Considerable medical research is being conducted worldwide into the use of radionuclides attached to highly specific biological chemicals such as immunoglobulin molecules (monoclonal antibodies). The eventual tagging of these cells with a therapeutic dose of radiation may lead to the regression ‑ or even cure ‑ of some diseases. Many therapeutic procedures are palliative, usually to relieve pain. For instance, strontium‑89 and (increasingly) samarium 153 are used for the relief of cancer‑induced bone pain.

21 Gamma caméra The first type are where single photons are detected by a gamma camera which can view organs from many different angles. The camera builds up an image from the points from which radiation is emitted; this image is enhanced by a computer and viewed by a physician on a monitor for indications of abnormal conditions.

22 SPECT SPECT (single photon emission computed tomography)

23 Tomographie par émission de positons
A more recent development is Positron Emission Tomography (PET) which is a more precise and sophisticated technique using isotopes produced in a cyclotron. A positron‑emitting radionuclide is introduced, usually by injection, and accumulates in the target tissue. As it decays it emits a positron, which promptly combines with a nearby electron resulting in the simultaneous emission of two identifiable gamma rays in opposite directions. These are detected by a PET camera and give very precise indication of their origin. PET's most important clinical role is in oncology, with fluorine‑18 as the tracer, since it has proven to be the most accurate non‑invasive method of detecting and evaluating most cancers. It is also well used in cardiac and brain imaging.

24 Examens de médecine nucléaire
Cœur Poumons Thyroïde Foie Cerveau Rein Rate Adrénals Squelette The thyroid, bones, heart, liver and many other organs can be easily imaged, and disorders in their function revealed. In some cases radiation can be used to treat diseased organs, or tumours. Positioning of the radiation source within the body makes the fundamental difference between nuclear medicine imaging and other imaging techniques such as x‑rays. Gamma imaging by either method described provides a view of the position and concentration of the radioisotope within the body. Organ malfunction can be indicated if the isotope is either partially taken up in the organ (cold spot), or taken up in excess (hot spot). If a series of images is taken over a period of time, an unusual pattern or rate of isotope movement could indicate malfunction in the organ. A distinct advantage of nuclear imaging over x‑ray techniques is that both bone and soft tissue can be imaged very successfully. This has led to its common use in developed countries where the probability of anyone having such a test is about one in two and rising. The mean effective dose is 4.6 mSv per diagnostic procedure.

25 Radionucléides médicales
Sous-produit Matières produites par les accélerateurs 67Ga 201Tl 123I 81Rb 81mKr 111In 11C 13N 15O 18F 99Mo 99mTc 51Cr 60Co 64Cu 165Dy 169Yb 125I 131I 192Ir 59Fe 32P 42K 188Re 153Sm 75Se 24Na 89Sr 133Xe 127Xe 90Y 103Pd 137Cs 198Au 106Ru This is a list of radionuclides used in medical procedures including Nuclear Medicine and Radiation Therapy. Byproduct Materials (Reactor Radioisotopes ) Molybdenum‑99: Used as the 'parent' in a generator to produce technetium‑99m, the most widely used isotope in nuclear medicine. Technetium‑99m: Used in to image the skeleton and heart muscle in particular, but also for brain, thyroid, lungs (perfusion and ventilation), liver, spleen, kidney (structure and filtration rate), gall bladder, bone marrow, salivary and lacrimal glands, heart blood pool, infection and numerous specialised medical studies. Chromium‑51: Used to label red blood cells and quantify gastro‑intestinal protein loss. Cobalt‑60: Used for external beam radiotherapy. Copper‑64: Used to study genetic diseases affecting copper metabolism, such as Wilson's and Menke's diseases. Dysprosium‑165: Used as an aggregated hydroxide for synovectomy treatment of arthritis. Ytterbium‑169: Used for cerebrospinal fluid studies in the brain. Iodine‑125: Used in cancer brachytherapy (prostate and brain), also diagnostically to evaluate the filtration rate of kidneys and to diagnose deep vein thrombosis in the leg. It is also widely used in radioimmuno assays to show the presence of hormones in tiny quantities. Iodine‑131: Widely used in treating thyroid cancer and in imaging the thyroid; also in diagnosis of abnormal liver function, renal (kidney) blood flow and urinary tract obstruction. A strong gamma emitter, but used for beta therapy. Iridium‑192: Supplied in wire form for use as an internal radiotherapy source for cancer treatment. Iron‑59: Used in studies of iron metabolism in the spleen. Phosphorus‑32: Used in the treatment of polycythemia vera (excess red blood cells). Beta emitter. Potassium‑42: Used for the determination of exchangeable potassium in coronary blood flow. Rhenium‑188 (derived from Tungsten‑188): Used to beta irradiate coronary arteries from an angioplasty balloon. Samarium‑153: Very effective in relieving the pain of secondary cancers lodged in the bone, sold as Quadramet. Also very effective for prostate and breast cancer. Beta emitter. Selenium‑75: Used in the form of seleno‑methionine to study the production of digestive enzymes. Sodium‑24: Used for studies of electrolytes within the body. Strontium‑89: Very effective in reducing the pain of prostate cancer. Beta emitter. Xenon‑133, Xenon‑127: Used for pulmonary (lung) ventilation studies. Yttrium‑90: Used for cancer therapy and as silicate colloid for the treatment of arthritis in larger joints. Beta emitter. Radioisotopes of palladium, caesium, gold and ruthenium are also used in brachytherapy. Cyclotron Radioisotopes Gallium‑67: Used for tumour imaging and localisation of inflammatory lesions (infections). Thallium‑201: Used for diagnosis of coronary artery disease other heart conditions such as heart muscle death and for location of low‑grade lymphomas. Iodine 123: Increasingly used for diagnosis of thyroid function, it is a gamma emitter without the beta radiation of I‑131. Rubidium‑81, Krypton‑81m: Krypton‑81m gas can yield functional images of pulmonary ventilation, e.g. in asthmatic patients, and for the early diagnosis of diseases and function of the lungs. Indium‑111: Used for brain studies, infection and colon transit studies. Carbon‑11, Nitrogen‑13, Oxygen‑15, Fluorine‑18: These are positron emitters used in PET for studying brain physiology and pathology, in particular for localising epileptic focus, and in dementia, psychiatry and neuropharmacology studies. They also have a significant role in cardiology. F‑18 in FDG has become very important in detection of cancers and the monitoring of progress in their treatment, using PET. Interestingly, in the United States, the federal agency responsible for radioactive material safety, the Nuclear Regulatory Commission, is only authorized to regulate Byproduct Medical sources. This limitation is imposed by the Legislation which created the NRC. The NRC has absolutely no jurisdiction over the use of Accelerator or Cyclotron produced radioactive material. That responsibility is left to the individual State Government Agencies responsible for Radiological Health. This results in some very unique situations since some radionuclides can be produced either in a Nuclear Reactor or by an Accelerator or Cyclotron. In those cases the origin of the radionuclide must be determined to ascertain whether the NRC has jurisdiction or not.

26 Quelques radiopharmaceutiques courantes
57Co/58Co (cyanocobalamin) 51Cr (chromate de sodium) 18F (FDG) 67Ga 111In ( chloride ) 123I ( iodure de sodium ) 125I (albumine de sérum humain) 131I (iodure de sodium) 131I (iodohippurate) 81mKr (gaz) Principales utilisations test de Schilling CGR  tomographie par émission de positons (TEP) tumeur des tissus mous et l'imagerie de marquage d'anticorps monoclonaux imagerie de la thyroïde déterminations du volume plasmatique fixation thyroïdienne, imagerie et thérapie études d'imagerie et de la fonction rénale imagerie de la ventilation pulmonaire This is a list of some common radiopharmaceuticals used in Nuclear Medicine Every organ in our bodies acts differently from a chemical point of view. Doctors and chemists have identified a number of chemicals which are absorbed by specific organs. The thyroid, for example, takes up iodine, the brain consumes quantities of glucose, and so on. With this knowledge, radiopharmacists are able to attach various radioisotopes to biologically active substances. Once a radioactive form of one of these substances enters the body, it is incorporated into the normal biological processes and excreted in the usual ways. Diagnostic radiopharmaceuticals can be used to examine blood flow to the brain, functioning of the liver, lungs, heart or kidneys, to assess bone growth, and to confirm other diagnostic procedures. Another important use is to predict the effects of surgery and assess changes since treatment. The amount of the radiopharmaceutical given to a patient is just sufficient to obtain the required information before its decay. The radiation dose received is medically insignificant. The patient experiences no discomfort during the test and after a short time there is no trace that the test was ever done. The non‑invasive nature of this technology, together with the ability to observe an organ functioning from outside the body, makes this technique a powerful diagnostic tool. For PET imaging, the main radiopharmaceutical is Fluoro‑dioxy glucose (FDG) incorporating F‑18, with a half‑life of just under two hours, as a tracer.

27 Quelques radiopharmaceutiques courantes
32P (phosphate chromique) 82Rb 153Sm (lexidronam) 89Sr 99mTc (pertechnétate) 99mTc (arcitumomab) 99mTc (bicisate) (ECD) Principales utilisations thérapie de tumeurs malignes endocavitaires imagerie par émission de positons tomographie traitement palliatif de la douleur osseuse de métastases osseuses imagerie de la thyroïde, les glandes salivaires, la muqueuse gastrique ectopique, les glandes parathyroïdes, dacryocystographie, cystographie Anticorps monoclonal contre le cancer colorectal imagerie de perfusion cérébrale A radioisotope used for diagnosis must emit gamma rays of sufficient energy to escape from the body and it must have a half‑life short enough for it to decay away soon after imaging is completed. The radioisotope most widely used in medicine is technetium‑99m employed in some 80% of all nuclear medicine procedures. It has almost ideal characteristics for a nuclear medicine scan (low energy photon, no beta, short half life) It has a half‑life of six hours which is long enough to examine metabolic processes yet short enough to minimise the radiation dose to the patient. Technetium‑99m decays by a process called "isomeric“ transition which emits gamma rays and low energy electrons. Since there is no high energy beta emission the radiation dose to the patient is low. The low energy gamma rays it emits easily escape the human body and are accurately detected by a gamma camera. Once again the radiation dose to the patient is minimised. The chemistry of technetium is so versatile it can form tracers by being incorporated into a range of biologically‑active substances to ensure that it concentrates in the tissue or organ of interest. Technetium‑99m is used in to image the skeleton and heart muscle in particular, but also for brain, thyroid, lungs (perfusion and ventilation), liver, spleen, kidney (structure and filtration rate), gall bladder, bone marrow, salivary and lacrimal glands, heart blood pool, infection and numerous specialised medical studies. Its logistics also favour its use. Technetium generators, are supplied to hospitals from the nuclear reactor where the isotopes are made. They contain molybdenum‑99, with a half‑life of 66 hours, which progressively decays to technetium‑99m. The Tc‑99m is washed out of the lead pot by saline solution when it is required. After two weeks or less the generator is returned for recharging.

28 Quelques radiopharmaceutiques courantes
99mTc (macroaggregated albumine) (MAA) 99mTc (médronate) (MDP) 99mTc (pentétate) (DTPA) 99mTc (sestamibi) 99mTc (du soufre colloïdal) (SC) 201Tl 133Xe (gaz) Principales utilisations perfusion pulmonaire imagerie de l'os imagerie rénale; ventilation radioaérosol l'imagerie par perfusion myocardique, imagerie de tumeurs du sein imagerie de RES (foie / rate), vidange gastrique, saignements gastro-intestinaux imagerie de perfusion myocardique, imagerie parathyroïde et de tumeur imagerie de la ventilation pulmonaire Myocardial Perfusion Imaging (MPI) uses thallium‑201 chloride or technetium‑99m and is important for detection and prognosis of coronary artery disease.

29 Accidents en médecine nucléaire
A woman was given 1000 times the intended dose of 131I by mistake.

30 Sources scellées pour le diagnostic
I25I pour “Rayons X rapide” Although rare, there are some sealed sources used for diagnostic purposes. pour un "xrayons rapide" 153Gd pour l'étude de la densité minérale osseuse (ostéoporose)

31 Radiothérapie Accélérateurs linéaires (rayons X ou électrons)
Téléthérapie (Sources scellées externe) - Traditionnel - Radiochirurgie stéréotaxique RADIOTHERAPY Rapidly dividing cells are particularly sensitive to damage by radiation. For this reason, some cancerous growths can be controlled or eliminated by irradiating the area containing the growth. Curiethérapie (sources scellées interne) - Débit de dose faible (LDR) - Haut débit de dose (HDR) - Intravasculaire (IVB)

32 Accélérateur linéaire
Rayons X Énergie unique 4 ou 6 MV Double énergie 6 et 15 ou 18 MV(énergie basse et haute) Electrons 4 MeV à 21 MeV - variables The linear accelerators of Varian and Siemens are shown. Linear accelerators are available with different photon and electron energies from various companies. Common photon energies available are 6 and 15MV or 6 and 18 MV and electron energies are usually provided from 4 MeV to 21MeV. Accelerateur Varian Accelerateur Siemens

33 Téléthérapie Tête Source
External irradiation can be carried out using a gamma beam from a radioactive cobalt‑60 source, though in developed countries the much more versatile linear accelerators are now being utilised as a high‑energy x‑ray source With any therapeutic procedure the aim is to confine the radiation to well‑defined target volumes of the patient. The doses per therapeutic procedure are typically 20‑60 Gy. Treating leukaemia may involve a bone marrow transplant, in which case the defective bone marrow will first be killed off with a massive (and otherwise lethal) dose of radiation before being replaced with healthy bone marrow from a donor. Tête Source

34 Source de téléthérapie
Capsule (Généralement 5,000-6,000 Ci) Cobalt-60 Source Pastilles 18 mm

35 Radiochirurgie stéréotaxique
m K n I f e 201 Co-60 sources environ 33 Ci chaque

36 Hôpital Ohio Etats-Unis (1975)
Accidents de Téléthérapie Riverside Methodist Hôpital Ohio Etats-Unis (1975) 400 patients surexposés

37 Sources de curiethérapie
Internal radiotherapy is by administering or planting a small radiation source, usually a gamma or beta emitter, in the target area.

38 Sources de curiethérapie
Caesium 137 Utilisé sous la forme de tubes, aiguilles, pastilles. Énergie convenable pour la curiethérapie Doit être remplacé une fois dans 15 à 20 ans en raison de leur plus longue demi-vie Principalement utilisé en curiethérapie gynécologique The lecturer may use this slide to explain the forms in which the Cesium 137 is available for radiation therapy. May also mention that tubes and pellets are used in mould and in gynecological brachy therapy and needles are used in implant. The energy of 662 keV is suitable for brachytherapy as it has considerably less shielding (radiation protection) compared to Radium and has steeper fall off of dose. The half life of 30 years is also suitable as it needs replacement once in 15 years or so and has reasonably higher specific activity.

39 Cobalt 60 Produit par bombardement de neutrons (capture de neutrons)
Disponible dans les formes d'aiguilles, de tubes et de granulés Demi-vie: 5,27 années Énergie: 1.17 MeV & 1.33 MeV (1.25MeV Ave.) Activité spécifique plus élevée Utilisé pour la curiethérapie à haut-débit de dose (HDR) The lecturer may use this slide to mention that Cobalt 60 which is mostly used in teletherapy is also used as brachytherapy source particularly for some high dose rate brachytherapy. This was mainly used in the form of tubes, needles and pellets and has a higher specific activity (shorter half life compared to Radium and Ceasium). Because of higher specific activity this was preferred as high dose rate brachytherapy source. However this is not a very popular brachytherpay source due to its high photon energy (1.25MeV avg.)

40 Ir-192 Produit par bombardement de neutrons (capture neutronique) de Ir 191 A une énergie optimale pour la curiethérapie (spectre de rayons gamma avec une énergie moyenne de 0,38 MeV) Activité spécifique plus élevée –Idéal aussi pour la curiethérapie à haut débit de dose Source de petite taille Disponible en différentes formes (fil, ruban) Doit être remplacé tous les 2-3 mois This slide may used to emphasize the fact that because of its higher specific activity Ir 192 could be used for high dose rate brachytherapy also and the most high dose rate remote after-loading brachytherapy units have Ir 192 as the source. The other advantage of its high specific activity is that miniaturization of the source size. Very small source of 4-5mm in length and 1.1mm in diameter could be made for high dose rate units with activity of 10Ci could be made. The other advantage of Ir 192 is that it could be made in the form such wires, ribbon which are flexible.

41 Autres Sources de curiethérapie I 125
Iode –125 : Demi-vie: 60,4 jours Énergie: 0,028 MeV (Ave) - faible énergie! Utilisé sous la forme de graines Implant permanent (par exemple prostate) Faible énergie donc protection contre les rayonnements est facile I-125 is widely used brachytherapy source for permanent implant of the prostate mainly due its short half life and low energy.

42 Autres Sources de curiethérapie Au- 198
Or 198 (Au-198) Énergie des photons: MeV Demi-vie: 2.7 days Graines, pastilles Implant permanent At this point the lecturer may mention that there are several other brachytherapy sources in use depending on the type of brachytherapy application. He may go on to explain one by one with the slides that follow. Au 198 (Gold 198) has a short half life making it suitable for permanent implant. It has a photon energy of MeV is also very suitable for brachytherapy. Due its short half life it is preferred for permanent implants.

43 Autres Sources de curiethérapie– Sr 90
Strontium 90 – Un émetteur bêta. En équilibre avec Y-90 produit de filiation Énergie: 0.5 MeV (Sr 90)/2.3 MeV (Y90) Demi-vie: 28,5 années The lecturer may use this slide to explain that Sr 90 is another brachytherapy source and is mainly beta emitter. The useful beta with energy 2.3MeV is from its daughter Y-90 which is in equilibrium with its parent Sr 90. Sr 90 has longer half life of 28.5 years and Y 90 has half life of 64.1.hours. This source is very much used in eye applicator (ophthalmic applicator) in brachytherapy. Recently Sr 90 source train is used in intra vascular application.

44 Autres Sources de curiethérapie– Pd103
Demi-vie: 17 jours Énergie des photons: MeV (Ave) –faible d'énergie! Utilisé sous la forme de graines Basse énergie - blindage est simple. Implant permanent au niveau de la prostate Palladium 103 is another brachytherapy used for mainly for permanent implant of prostate in the form of seed.

45 Chargement différé télécommandé
LDR et HDR unités Chargement différé télécommandé de sources radioactives offre la réduction de l 'exposition professionnelles  au personnel médical Augmentation de la capacité de traitement du patient Améliorations potentielles des résultats de traitement par l'utilisation de méthodes plus cohérentes de traitement The lecturer may now point out the advantage of remote after-loading units with respect to radiation safety. Since the sources are retracted while the nurse attends on the patient, the dose to staff during treatment in almost eliminated. However there are chances of radiation accidents remote after-loading units which will have to taken care

46 Accidents en curiethérapie
Hôpital Backus Connecticut (1994) 112 graines 125I implanté Activité incorrect (10 fois plus élevée)

47 Accidents en curiethérapie