 Hello everyone. So far we have been discussing the fundamentals of nuclear chemistry and then some of the analytical techniques based on nuclear phenomena and also the radiochemical techniques. Today's lecture I will describe some of the applications of radioisotopes in societal applications in the service of mankind like healthcare industry and so on. So before going to the actual applications let me explain what are the fundamental principles underlying these radioisotope applications. So there are mainly three concepts or three properties of these radiations that enable them to be useful in many many fields. So I will just explain them. The first one is the radio tracer concept. I had also explained it earlier one of the lectures on the tracer-based analytical techniques and the underlying principle is that the radioisotopes have the same chemical properties as their stable isotopes. So this property of radioisotopes helps them to trace the path of their stable isotopes. You take any industry or even a chemical reaction where you want to understand the mechanism of the chemical reaction then you can label one of the atoms with the radioactive atoms and see how this particular reagent is moving in the chemical system. Like sulfur containing chemicals their reactions can be studied by sulfur-35 labeled compounds. In fact many of the reaction mechanisms have been understood using radio tasers or labeled compounds. So we will discuss that applications in many many areas. Second property of these radiations is that these radioisotopes emit radiations that are highly penetrating and because of that high penetration power you will find many many applications of radioisotopes in the industry like datagraphy or even in the non-destructive testing investigations. You will see there are many of them. So this is the main concept. They can penetrate through thick absorbers like what I have shown here is that alpha particles will travel this way like if we have a fluid transmission experiment then I by I0 will follow four alpha particles they will travel same distance and after that there will be certain fall that is the typical transmission graph for alpha particles whereas the gamma radiation will follow exponential decay. So there I could be a landlord law. So you can use make use of this intensity decrease with thickness of absorber in many many applications. And the third is the effects of radiation. Now there is any radiation can effect can create defects they can generate free radicals they can produce heat they can even kill pathogens and they can damage the cells and these properties of these radiations find them very useful in medicine for example in cancer treatment therapy of cancer and also modifying materials by polymer like polymerization or you can create defects in materials like diamonds you know you can create the different colors in diamonds and add their value they produce heat they can you can use them as a source of heat like the 38 plutonium is used in satellites as a source of heat so you can power like pacemakers then they can kill pathogens so that this is utilized in us in food technology you can prevent this prouting of the fruits and many many applications they can even induce mutations in seeds and you can produce improved varieties of crops by using radiation induced mutations. So the list is endless and I will cover some of the examples of these three concepts in my talk. So first let me in this particular talk discuss the applications of radio isotopes in healthcare and this applications could be based on radio tracer concept or they could be based on the radiation effects on in the human body so all sort of applications can come. So in radio isotope applications healthcare one of them is in vitro that means in the test tube in the laboratory you can do analytical determinations of the different biological components of our human blood or many other you know bio fluids you can determine for example we discussed in the radio and the techniques the radio immuno assay where you can determine the concentration of T3, T4, TSH or even other like prostate specific antigens you can determine by using labelled antigens and interacting them antibodies and then finding out the concentration of these molecules at very very low levels like nanomolar concentrations but they are done in the laboratory. In vivo in the body if you introduce radio isotopes then you can do investigations of diseases and the chemicals that are introduced in the in the body in vivo they are called radio pharmaceuticals they are like medicines they are pharmaceuticals compounds but they are labelled with the radio isotopes so we will discuss them in this lecture and also the radio isotopes by virtue of their radius and effects by virtue of killing the tumor cells we can use them in therapy and lastly the sterilization of medical products this medical products you know when they are implements the tools the suture the seizure the tweezers and on different implements used in operations so they have a chance of getting you know in effect infected again during handling so in this particular case what happens you can pack them you can pack them in a cardboard boxes take them to the plant for irradiation and after irradiation they will be opened only when they are being used for the operation so you can sterilize the medical products implements tools by using registries I will not discuss this much in this particular talk but I will talk about first two diagnosis and the therapy okay so now let us discuss what are radio pharmaceuticals so radio pharmaceuticals are pharmaceutical compounds but they are labelled with the radio isotopes so a special radiochemical formulation the formulation is a radiochemical is a compound of adequate purity so it should have a desired radiochemical purity radio nucleic purity that is what we mean by adequate purity and pharmaceutical safety so there are pharmacopoeia for different their quality control measures to be taken with regard to pH sterility and so on pyrogenicity so it should be suitable for oral or intravenous administration to humans for performing a diagnostic test or for treatment so any any no compound to be injected intravenously or orally in the human body has to pass the tests of this this kind of quality control measures so the pharmaceutical safety is important so that we will discuss in my talk so this is a general definition of a radio pharmaceutical now radio pharmaceutical can be used in diagnosis diagnosis of diseases wherein we image we take the image of an organ it could be static or we can see the dynamic flow of the body fluid of the blood then we can get the dynamic image of an organ how they metabolism is taken place in the human organ so that you can do using diagnostic applications where you inject the radio isotope labelled with compound and then in the body wherever this radio isotope is going that particular organ we can do they take the image in static or in a dynamic or you can have sequential images so this is another application and then we have the therapeutic applications where you can do you can use radio nuclei externally it's called teletherapy from outside we can expose the cancerous tissues and kill them or we can introduce the radio isotope in the body either by a shield source in a cavity or by using a radio isotope labelled compounds so this radio isotopes essentially are emitting those which are introduced in the human body in the form of a compound like radio pharmaceuticals they have to have particulate emission like beta plus or alpha beta minus or alpha so that they can do the damage to the cancerous tissues so in radio pharmaceuticals if you inject into the human body then they are required to have particulate emission beta alpha so that they can kill the tissues in their nearby city so that is the kind of requirement we have for the pharmaceutical in therapy okay so let us see for diagnosis diagnostic applications what are the kinds of radio isotopes we can choose for diagnosis as a pharmaceutical so one of them is the decay mode the decay mode see what we are doing we are going to take the image of the organ in which the gamma the radio isotope is distributed so it should preferably emit only gamma ray so it should not be emitting a particulate because that particulate will unnecessarily damage that issue so there are not many radio isotopes it should be not emitting particulate because the gamma is emitted only after beta or alpha decay so but there are like internal transitions the isobaric state is there like technician 99m it will decay by only internal transition to 140 kV is the gamma ray and having half type of 6 hours that is an ideal for diagnostic pharmaceutical first is that it should not emit preferably any particulate emission the second is that the energy of the gamma ray should be in the range of 100 to 200 kV why because if it is below the 100 kV energy then it will be stopped in the body itself which will not come out of the body and if it is more than 200 kV then the efficiency of detection will be low so 100 to 200 kV is the optimum range of gamma energy for a good image that is the reason why gamma energy should be in 100 to 200 kV more than 200 it is since it will go down less than 100 the gamma ray will not come out for the body it will be attenuated by the human body. A flight should be short preferably few hours again the reason why it is so because you do not want the radio isotope to be in the body after the image has been taken so it should come out of the body or it should tie down in the body itself so that few hours science have optimum for the diagnostic investigation. Lastly it should have a versatile chemistry that means it should be able to complex different metal ligands and it should those ligands having high affinity to different organs so a particular metal ion multiple oxygen state will be ideal because different ligands may bind in metal ion different oxygen state. Some of the examples of these radio isotopes that are used in diagnosis are technosome 99m ideal in fact it is called the work horse of nuclear medicine about 80% of the nuclear medicine investigations for diagnosis are done using technosome 99m. So gamma ray is ideal half-life is ideal indium 111 ideal gamma ray energy but half-life is little long 123 iodine half-life is and gamma ray wise ideal that is why there is huge demand for 123 iodine though it requires a genome target enriched genome helium 101 you can see half-life and gamma engines are quite good gallium 67 3.26 days and good and iodine 131 though the half-life is long in you will find in many applications it is very very useful it can be used in both diagnosis and therapy it has the gamma ray energy it has the particulate emission function. Now once you label a compound and prepare a radiopharmaceutical there are certain pharmaceutical quality control measures you must establish and this belongs to the physicochemical control, radiochemical control and biological control. In physicochemical properties you should inspect the solution that this should be clear this should not be an turbidity pH should be the proper zone which will be incompatible with the body the chemical purity of the compound there should not be any other impurities and sometimes you use in the particulate form you know some some micro spheres are used for some treatment so the particle size would be in the proper range. The radiochemical control regards to radioactive concentration what is the concentration of radioisotope is millicury or microcury or curie. So you know depending upon the requirement specified by the doctor and do nuclear medicine personnel you should specify that concentration radio nucleic purity there should be no unwanted radioisotopes and the radiochemical purity the chemical form of that molecule should be whatever is the desired. For example if you have fluorine in fluorine fdg then fdg should be only there should not be any other derivative of fdg so that kind of purity has to be established. So there are measures to specify to determine the radiochemical purity by that thin layer chromatography or p-pachromatography radio nucleic purity by gamma spectrometry radioactive concentration by counting the sample. Then you have the biological control sterility for injectables you would have to have to be sterile it should be the pyrogenicity means it should not produce heat in the body. So this is a very important requirement of the pharmaceutical and it should be distributing in the organ of your interest. So these are the properties that pharmaceutical should have. So I have just given you a figure that whatever different organs in the body which are likely to get affected by a disease then there are radio pharmaceuticals both in terms of the radioisotopes as well as the molecule which for which there has been hardly there in development to produce those kind of pharmaceuticals which will be selectively going to the particular organ. For example you want to see the glucose metabolism in the brain then you have fluorine 18 labeled fdg you want to see the thyroid update thyroid functioning if whether there is any malfunctioning of thyroid you can do sodium iodide labeled with 131 iodine or even you can do technetium 99m because technetium also can go to thyroid. Then for heart you have a apetine fdg and there are there is one thalium also thalium 201 also will go to heart so you can do for stress test. Then for bones you have the you have ethylene diamine tetra ethylene phosphinic acid sulfur asomerium labeled fdg TMP or you can have asperus labeled orthophosphate again for the bones you have volume 156 hydroxyapatite. So in fact there are some of the few you will find that for example for the prostrate there are prostrate specific antigens. So if you label that antigen with a particular compound like lutecium it will selectively go to prostrate and you can do the image as well as you can do the treatment of the prostrate case. So for every organ almost every organ in the human body you will find there is a particular pharmaceutical and if there is a proper labeling a device at all so you can do imaging of different organs of the body. Now what are the experimental techniques for this you have this technique called for imaging scintigraphy and it is also called the single photon emission tomography spec. So the principle of spec is that suppose you have the organ which is containing the radioisotope here and this organ is now in the human body it is emitting gamma radiation isotropical. So you from outside this is the machine for respect so the camera this is the camera you the patient is made to lie on this and the camera will detect the gamma ray coming out from the organ. Now the radioisotopes emitting gamma ray in all directions but you have detector only one side and you want to take the spatial image so as a function of as a space in space how the organ is distributed that means how the activity is distributed in the organ. So you have a detector where the gamma ray is made to pass go to the detector through collimators. So it will go at a particular angle so that tell you in which bin this gamma ray has come. So you can this is segmented kind of system. So this collimation helps you finding out the place from which the gamma ray has come. Then the gamma rays are detected by the detector mostly scintillator, sodium iodide, helium or BGO type of scintillators. And there are PMT photo multiplier tubes to take convert the signal the photons converted into electrons at a PMT. And then there is a position sensitive position sensitive circuit to identify from which place in the organ the particular gamma ray has come. Like for example this collimation will give you this particular position. So we can see in organ and we can construct the image by help of a computer. So that is the principle behind the spectrum. So it essentially gives you the 3D image of the organ in static or in dynamic. Like this is just to give an example expect images like for this Technician 99M labeled a MIBI. It is called MIBI, Mythoxy isobutyl isonitrile and it is a heart imaging agent. You inject intravenously this Technician 99 MIBI and after 15 minutes you take the image of the heart of the person from outside. Externally you are non-invasively you are monitoring the gamma rays that is coming out of the human body and you can see as a function of time how the when the heart is pumping the blood you can see the different images different cross sections of the heart and if a particular portion has got infractuous that means in the blood is not reaching there the muscles are dead you can identify the doctor can identify which portion of the heart has become infractuous means it is dead. So that kind of a investigation can be done using pharmaceuticals labeled with proper radioisotopes. Similarly you have this scintigraphy image of Lutisium 177 labeled EDTMP in DOCS which are with how to be having osteosarcoma. You can see this is how you keep the patient in the expect machine and you can see the inflammation so the sarcoma that the particular tumor in the animal can be seen in the bright intensity of the radiation the radioisotope is going and depositing there. So you can see that you can even the Lutisium 177 not only can do the diagnosis by means of gamma ray you can also do the treatment because therapeutic application requires emission of high energy beta particles which Lutisium 177 emits. Now that was the spec imaging so you just single the photon emitting radioisotope and you take the camera and it will take the image of the organ but resolutions in the spec are not very high and therefore the positon emission tomography peak pet has become now more popular because of the resolution in terms of the space the spatial resolution is excellent in pet and pet you require a positon emitter the positon emitters are carbon-11, nitrogen-13, oxygen-15, fluorine-18 and also gallium-68. You can see their half lives are minutes and the beta plus positon energy and the way they are produced. So exotin is in fact these days most commonly used because it is having a half life of about two hours so from the cyclotron they can be transported to the hospitals whereas the other isotopes carbon-11, nitrogen-13, oxygen-15 their half lives are even less than 20 minutes and so they require the cyclotron to be present in the hospital. So immediately you transport the pharmaceutical to the hospital within few minutes and then you can do the pet analysis but fluorine-18 you can take from cyclotron to other hospitals in the city and another thing is gallium-68 is one another very interesting pair it is a generator you have germanium-68 decaying to gallium-68 and you can take the you can take the generated to the hospital and we milk the gallium-68 which is then injected into the one body for pet investigations. So this is again the principle behind the positon emission tomography. So now you have a ring of detectors which is not single detector you have a ring and the patient like MRI it is like MRI so the patient is made to lie here is the detectors in circle the patient. So suppose you have an organ here it is odd shape organ and then from different parts of this organ the gamma rays the positons are anyway annihilated so gamma rays are emitted and the 511 KV gamma ray they are emitted at 180 degree so you know the positon emission and so from a particular point you will see that the two detectors will receive an event at 180 degree. So similarly this event is these two events are coming from this place so this because of the coincidence phenomena you can identify from which place in the in the organ the the higher level gamma ray has come. So this is the schematic you have a this is actually a annular one this is a circle it is a cylinder type of thing and then this is a BGO detector a way and it is like circular array and then this data are fed to the computer to do the you know investigation to computer simulate the distribution of activity in the organ. So from sub pet machine very compact machine and in the cyclotron the arms you produce the positon emitter you have to have the very fast chemistry there is a radiochemical unit which will separate the radiochemical and then you can level them and then transport to the hospital. So this is the general principle of the pet machine and the images that you get from the spec versus pet you can see this is the image of a brain using spec and pet so you can see the mark difference improvement in the image of the brain using pet vis-a-vis the spec image that is why now the spec is becoming very very popular among the nuclear medicine practitioners. Now let me come to the another application of radioisotopes is therapy therapy of cancer and here there are three techniques one of them is tele therapy as the name itself implies the radioisotopes from outside the body and you concentrate the you focus the beam of a gamma ray onto the organ that is to be irradiated people use koval 60 source which is emitting high energy gamma ray 1.17 and 1.33 MeV and the gamma rays are focused onto the tumor so you have to put it in the proper shield and then allow only a beam of gamma ray to come though the gamma ray is emitted in all directions but you are collimating the gamma ray to come to a particular tumor so then there is a huge activity required because you cannot focus the gamma ray only you can collimate so about 12,000 tury of koval 60 is used in one machine or it is tele therapy so this is where the patient lies and this is the source koval so you can it is not a shield and the the gamma ray emitted is the koval 60 is emitting gamma ray to irradiate the particular organ so though koval 60 is most commonly used there are now advancements going on you can produce gamma ray from electron beam by means of beam Stalin you can use protons for therapy and you can use boron neutron catheter therapy that means you suppose you can you can you want to produce protons you can have neutrons you can you can have a neutron source for treatment of the cancer so you use borons and the neutron will induce the reaction in the boron and give you alpha and lithium 7 so this alpha and lithium 7 essentially what will happen so this alpha and lithium 7 are now highly charged particles highly charged particles and they will damage the cancerous tissue so you have to take boron level compound to that organ nearby that organ and bombard with neutrons selectively because boron has got very high perception for neutrons you can do the damage of cancerous cells by using this technique so there are many techniques which are being used for cancer treatment one of them is teletherapy other one is brachytherapy not all cancers can be treated by teletherapy because from outside you cannot take the gamma ray to particular organ particularly the deep-suited tumors like cervical cancers prostate cancers ocular cancers you know eye cancers so these are deep-suited so you you may unnecessarily damage the other organs so the those tumors which are not available by teletherapy they are treated by brachytherapy brachytherapy you use tiny sources they are placed in a cavity well which can be placed in a cavity and the particularly people use 192 iridium and 125 iodine 125 iodine has a half life of 60 days and gamma ray energy is 35 kV or so and 192 about 100 200 kV gamma rays so you put the the sources for a particular period of time and after that these are sealed sources so they are not going with the blood bloodstream you can just take them out after proper exposure these are the typical you know this this needle-shaped pins source they are sealed sources they are called ocuprostra sheets because they can be used for ocular cancer as well as prostate cancer so they are they are made in the laboratory and this is the typical drawing of the feed you can see the length of this is 4.5 millimeter and the diameter is of the drop 0.8 mm so very thin tiny needles and wires look like wires they can be placed behind the eye and placed in the other places of the human body so wherever you want to do the treatment the prostate cancer so you want to irradiate the prostate with the this gamma rays you can do that and the lastly we have the radionuclide therapy radionuclide therapy is that like radionuclide pharmaceuticals used for diagnosis then you can tag the radionuclide pharmaceutical with the radionuclide which is emitting the particulate emission and then do therapy so the radionuclide will take the radionuclide to a particular organ and the radionuclide will limit the particulate gamma a particular radiation alpha or beta and that will kill the tensor system so 131 iodine is used for thyroid disorders yttrium 94 treatment of arthritis and phosphorus 32 for skin cancer yttrium 90 and phosphorus 32 are pure beta emitters the high-energy beta is described the tumor cells and so for example iodine you can use the beta for thyroid disorders so even for therapeutic agents you know but if you have some joint diseases like arthritis then there are radioisotopes like yttrium 90 rbm 169 rhenium 186 they can use for treatment of joint diseases one of the examples we can see here immediately after the treatment the the distribution of that you have the arthritis you know so there is some fluid deposition and that you can take the image of that knee with these radioisotopes after three months of treatment or after six months of treatment you can see that the patient is recovering that particular inflammation is going off so this image is taken with yttrium 90 hydroxyapatite for treatment of arthritis so you can use these radioisotopes which are emitting particulate radiation for treatment of many types of diseases and lastly there are theranostics means therapy and diagnosis so they have dual purpose of not only doing therapy but also diagnosis so they are called this is a new concept coming up last few years now the radioisotopes having dual properties so they emit particulate radiation like beta alpha and also they emit gamma radiation and therefore they can be used for both diagnosis and therapy so for example when a patient is undergoing iodine therapy you can monitor the therapy what is happening to the patient as a function of time using gamma ray emission so iodine 131 is one of the isotopes it has got a beta minus and a gamma ray and 177 lutecium is another isotope which has got a very good chemistry ideal gamma ray energy 100 to 200 and half line and particulate radiation so this is the image of lutecium 177 hydroxyapatite which is used for treatment of arthritis in medium-sized joints like elbow, wrist and ankle and you can see immediately after therapy and then after one month of the therapy how the inflammation is vanishing as a function of time so this is how one can carry out investigations of therapeutic applications of radioisotopes you can do teletherapy you can do bachytherapy and if you support there are it in the in the tumor is in the glands sometimes even the bachytherapy will not help so you can go for radionuclide therapy and the theranostic ones help you not only in therapy but also in diagnosis as a function of time while the therapeutic treatment is going so that's all I had to say in this particular one the next lecture I will talk about the other applications of radioisotopes in industry and so thank you very much