HAPPY NEW HAPPY NEW ACADEMIC YEAR ACADEMIC YEAR (2009(2009--2010)2010)

PHARMACEUTICS IIIPHARMACEUTICS IIITopics in this course are related to special Topics in this course are related to special considerations for the:considerations for the:Sterile dosage FormsSterile dosage Forms*Parenteral products*Parenteral products*Vaccines*Vaccines*Blood, fluids, electrolytes and *Blood, fluids, electrolytes and hematological drugshematological drugs*Ophthalmic pharmaceutical products*Ophthalmic pharmaceutical products**ComplexationComplexation and protein bindingand protein binding**RadiopharmacuticalsRadiopharmacuticals

Dr/ Samar MansourDr/ Samar MansourAssociate Professor of PharmaceuticsAssociate Professor of Pharmaceutics

RadiopharmaceuticalsRadiopharmaceuticals

Overall Aim Overall Aim

After the completion of this part of the course the student should be able to:

Comprehend principles of radioactivity Comprehend principles of radioactivity and its pharmaceutical, diagnostic and and its pharmaceutical, diagnostic and therapeutic applicationstherapeutic applications

RadiopharmaceuticalsRadiopharmaceuticalsRadiopharmaceuticals are medicinal Radiopharmaceuticals are medicinal

products that are radioactive.products that are radioactive.

Principally in the branch of medicine known as:Principally in the branch of medicine known as:

They are used forThey are used for

DiagnosisDiagnosis RadiotherapyRadiotherapy

Nuclear MedicineNuclear Medicine

II-- RadiotherapyRadiotherapyTTreatmentreatment of of diseasedisease by by radiationradiationThe radioactive material, when present in a tissue or organ in sufficient quantity, will produce emanation (energyenergy) capable of destroying existingdestroying existing cells and preventing the formation of new tissue.Applied to:(1) TumorsTumors(2) Conditions in which an organ produces physiological harm through overactivity.

IIII--DiagnosisDiagnosisFor diagnosis, The radioactive material are used as

Example:Organ and tumor visualization: Photoscan.Organ and tumor visualization: Photoscan.Dense regions in the scan are indicative of regions of high activity

Radioactive Tracers

Radiopharmaceuticals are used for:Radiopharmaceuticals are used for:

RadiopharmaceuticalsRadiopharmaceuticals*Radiopharmaceuticals vary from *Radiopharmaceuticals vary from inorganic inorganic

saltssalts to large to large organic moleculesorganic molecules and and complexescomplexes

*Radiopharmaceuticals contain*Radiopharmaceuticals contain either:either:long halflong half-- lives lives radionuclidesradionuclidesobtained from obtained from

Commercial SuppliersCommercial Suppliers

* They are prepared in a variety of dosage * They are prepared in a variety of dosage forms which includeforms which include

Short halfShort half-- lives lives radionuclidesradionuclides

prepared in prepared in Hospital Hospital RadiopharmaciesRadiopharmacies

I.V. injectionsI.V. injectionsGasesGases AerosolsAerosols CapsulesCapsules

Oral Oral SolutionsSolutions

Constituents of the AtomConstituents of the Atom• The simplest model of the atom is shown in the diagram below:

The basic building of atoms :Positively charged nucleus (composed of protonsand neutrons) with associated orbital electrons.

The basic building of atomsThe basic building of atoms

- Electrons, Protons, and Neutrons constitute the basic building blocks of atoms, both stable and radioactive.

• The number of orbital electrons is equal to the number of protons in the nucleus.

- The electron is the smallest of these three particles. Its mass, me, is 9.1091 x10-28 g

- The mass of the electron, me, is used as a unit of mass

- The Electron is assigned a charge of – 1. - The charge of the Proton is +1 (1836 mass e)1836 mass e)

- The charge of the Neutron is zero(1838 mass e)1838 mass e)

-

Atomic StructureAtomic Structure (Cont.)(Cont.)•• A NuclideA Nuclide is an atom described by its atomic number (Z) is an atom described by its atomic number (Z)

and its mass number (A). and its mass number (A). Nuclides may be stable or Nuclides may be stable or unstableunstable

•• The atomic number (Z) is equal to the charge (number of The atomic number (Z) is equal to the charge (number of protons) in the nucleusprotons) in the nucleus, which is a characteristic of the , which is a characteristic of the elementelement

•• The neutron number, N, is the number of neutrons in the The neutron number, N, is the number of neutrons in the nucleus. nucleus.

•• The mass number, A, is equal to the sum of the protons The mass number, A, is equal to the sum of the protons and neutrons and neutrons in the nucleusin the nucleus . .

•• Thus, Thus, A = Z+NA = Z+N

•• AA 3232•• Chemical symbol, e.g. P (PhoChemical symbol, e.g. P (Phosphorus) sphorus) •• ZZ 1515

P+N

P•Radionuclidesunstable nuclides are radioactive

Nuclides and IsotopesNuclides and Isotopes•• IsotopesIsotopes are Nuclides with the same number of are Nuclides with the same number of

protons but with different numbers of neutrons. i.e. The protons but with different numbers of neutrons. i.e. The same atomic number but differ in mass number.same atomic number but differ in mass number.

•• For example, For example, deuteriumdeuterium (2,1H) and (2,1H) and tritiumtritium (3,1H) are (3,1H) are isotopes of hydrogenisotopes of hydrogen with mass numbers two and with mass numbers two and three, respectively. Only three, respectively. Only (tritium) is radioactive (tritium) is radioactive

•• Radioactive nuclides or radioisotopesRadioactive nuclides or radioisotopes can generally be can generally be described as those which have described as those which have an an excessexcess or or deficiencydeficiencyof neutrons in the nucleusof neutrons in the nucleus..

•• There are 200 stable nuclides and over 1100 unstable There are 200 stable nuclides and over 1100 unstable (radioactive) nuclides(radioactive) nuclides

•• 1H, 2H, 12C, 23 Na are 1H, 2H, 12C, 23 Na are stable nuclidesstable nuclides•• 3H, 14C, 22 Na are unstable 3H, 14C, 22 Na are unstable RadionuclidesRadionuclides

Radioactive decay (Radioactive decay (Radioactivity)Radioactivity)• Radioactive decay or radioactivity is the process by which

an unstable atomic nucleus (radionuclides or radioisotopes) can regain stability by nuclear transformation emitting radiation in the form of particles or electromagnetic wavesto attain a more stable state and the nucleus may be transformed into another.

•• AA--Natural radioactivity:Natural radioactivity:The stability of the atoms depends on the neutron to proton (N/Z) ratio in the nucleus. Above atomic number 83, all elements are radioactive. The nucleons are in a state of continual motion (naturally occurring radionuclides).

Example: Uranium (238)- Radium (226). BB-- Artificial radioactivity:Artificial radioactivity:

• Radioactivity could be through an artificial transmutation. Radioactivity could be through an artificial transmutation. e.g. the e.g. the bombardment of nitrogenbombardment of nitrogen of N=14 with a of N=14 with a heliumhelium nucleus) to nucleus) to produce radioactive oxygen produce radioactive oxygen 14 4 1 17 14 4 1 17

N + He H + ON + He H + O7 2 1 87 2 1 8

((Radioactivity)Radioactivity)•• RadioactivityRadioactivity is a spontaneous process by is a spontaneous process by

which the unstable atoms of an element emit which the unstable atoms of an element emit or radiate excess energy in the form of or radiate excess energy in the form of particles or waves.particles or waves.

•• These emissions are called ionizing These emissions are called ionizing radiations.radiations.

•• Depending on how the nucleus loses this Depending on how the nucleus loses this excess energy eitherexcess energy either::

AA-- a lower energy atom of the same form will a lower energy atom of the same form will result, result,

BB-- or completely different atom can be or completely different atom can be formed.formed.

Radiation from Radioactive Radiation from Radioactive NucleiNuclei

• The most frequently types of radiation emitted from radioactive nuclei.

Alpha Beta Gamma Rays

Electromagnetic Radiation

(photons)

Negatron and Positron

ParticlesParticles

Radiation from Radioactive Radiation from Radioactive NucleiNuclei

1. Alpha RadiationAlpha Radiation• They are compound particles consisting of

two protonstwo protons and and two neutronstwo neutrons.• Thus, the alpha particle is identical with

the helium nucleus. • The range of alpha particles in air is about

5 cm, and less than 100µ in tissue.

Radiation from Radioactive NucleiRadiation from Radioactive Nuclei2. Beta Radiation*They are electrons emitted from radioactive nuclei.*When these electrons are emitted from radioactive

nuclei, they are called Beta particles. *They are two types because there are two kinds of

electrons emitted, A- The negative electron (negatron, β-) b- The positive electron (positron, β+ )

*The positron is identical with the negatron in all respects except for its charge of +1 instead of –1.

*The two particles are the same as e- and e+, except for their origin.

*Beta particles may have a range of over 10ft in air and up to about 1 mm in tissue.

3. Gamma Radiation• It is electromagnetic, whereas alpha and beta

radiations are particulate. • Gamma rays are radiated as photons or

quanta of energy• Gamma rays are the most penetrating of all

types of radiation emitted by radioisotopes Can easily pass through more than a foot of tissue or several inches of lead.

Radiation from Radioactive NucleiRadiation from Radioactive Nuclei

Radiation from Radioactive Radiation from Radioactive NucleiNuclei

Common Particles of NatureCommon Particles of Nature

0000γγGamma Rays Gamma Rays 0000ννNeutrinoNeutrino

7346(2N+2P)7346(2N+2P)+2+2ααAlphaAlpha1838 mass e1838 mass e00nnNeutronNeutron1836 mass e1836 mass e+1+1ppProtonProton

11

11

+1+1

––11

e+(e+(ββ++))

ee––

Positron Positron (nucleus)(nucleus)

ElectronElectron(shells)(shells)

11––11ee–– ((ββ––))Negatron Negatron (nucleus)(nucleus)

Mass Mass ChargeChargeSymbolSymbolParticleParticle

Modes of Nuclear DecayModes of Nuclear Decay1. Alpha 1. Alpha -- Decay (Decay (αα -- emission)emission)

• This occurs with large nuclei, predominantly with nuclides of atomic number greater than 83. It involves the emission of an α - particle (helium nucleus He), i.e.,

• A A-4 4• X Y + He + Q• Z Z -2 2

• For example : • 226 Ra 222 Rn + 4 He

Radium Radon

energy

Alpha Alpha -- DecayDecay

Alpha decay of the 238U "parent" nuclide produces 234Th as the "daughter" nuclide.

ThoriumUranium

2. Beta 2. Beta –– DecayDecaya. Negatron (a. Negatron (ββ ––) emission) emission

•• Nuclei with excess neutronsNuclei with excess neutrons gain stability by the conversion of a neutron into a proton plus (β –) particle.

• (β –) particle has a very low mass there is no change in the mass number, but the atomic number

•• 1 1 01 1 0•• n P + n P + ββ + + νν•• 0 1 0 1 --11

A A o A A o •• X Y + X Y + ββ + + νν•• Z Z+1 Z Z+1 --11

•• 32 32 3232 00•• P S + P S + ββ + + νν•• 15 16 15 16 --11

Increases by one unitIncreases by one unit

•• This process is occurs with This process is occurs with neutron deficient nucleineutron deficient nuclei. The . The deficiency being rectified by the deficiency being rectified by the conversion of a proton into conversion of a proton into a neutron plus a positron.a neutron plus a positron. Positrons are emitted with a Positrons are emitted with a continuous energy spectrum.continuous energy spectrum.

•• There is no change in mass number but the atomic numberThere is no change in mass number but the atomic number

• P n + β + + νν

•• 58 58 5858 0 0 •• Co Fe Co Fe + + ββ + + νν

27 26 +1 27 26 +1 •

2. Beta 2. Beta –– DecayDecayb. Positron (b. Positron (ββ ++) emission) emission

Decreases by one unitDecreases by one unit

Cobalt Iron

3. Electron capture (EC, K3. Electron capture (EC, K-- capture)capture)•• This is an alternative for This is an alternative for ββ + emission decay with + emission decay with neutron neutron

deficient nuclei.deficient nuclei.•• It involves the It involves the conversion of a proton into a neutron by conversion of a proton into a neutron by

capture of an orbital electron from Kcapture of an orbital electron from K--shellshell because because electrons in this orbital are the closest to the nucleus.electrons in this orbital are the closest to the nucleus.

•• 1 1 1 1 •• P + eP + e –– nn•• 1 01 0•• This capture causes a deficiency in the K shell, by the This capture causes a deficiency in the K shell, by the

migration of an electron of the outer shells. Since migration of an electron of the outer shells. Since the the migrant electron loses energy in the process, the surplus migrant electron loses energy in the process, the surplus energy is emitted in the form ofenergy is emitted in the form of XX--ray ray of an energy of an energy characteristic of the product atom. characteristic of the product atom. XX--rays are photons emitted rays are photons emitted during energy level transitions of orbital electrons.during energy level transitions of orbital electrons.

•• 55 55 5555•• Fe + e Fe + e -- MnMn + + MnMn X X -- raysrays

26 2526 25•• the mass number remains the mass number remains •• unchanged but the atomic numberunchanged but the atomic number

Decreases by one unitDecreases by one unit

4. Nuclear Fission (Nuclear reactor)4. Nuclear Fission (Nuclear reactor)•• Large nucleiLarge nuclei tend to be tend to be unstable and splitunstable and split into into two two

fragments. fragments. This process can occur This process can occur spontaneouslyspontaneously but it is but it is extremely extremely slow.slow.

•• Natural uraniumNatural uranium, the process has a half, the process has a half--life of about life of about 0.9x100.9x1066 years. years.

•• However, However, if if large nucleilarge nuclei are irradiated with neutronsare irradiated with neutrons of of sufficient energy the resultant sufficient energy the resultant neutron captureneutron capture results in a results in a very very high degree of instabilityhigh degree of instability and and fission occursfission occursimmediately immediately accompanied by the accompanied by the ejection of one or more neutronsejection of one or more neutrons..

•• This process is the basis ofThis process is the basis of operation of the Nuclear operation of the Nuclear ReactorReactor, in which a , in which a sufficient bulk of sufficient bulk of fissile materialfissile material (235U (235U or 239Pu) is brought together so that or 239Pu) is brought together so that the neutrons emittedthe neutrons emittedin the occasional in the occasional spontaneous fissionspontaneous fission have a high have a high probability of probability of capture by other nucleicapture by other nuclei..

•• The latter disintegrate promptly to The latter disintegrate promptly to yield neutronsyield neutrons which which are captured in turn, resulting in aare captured in turn, resulting in a

•• ..Self Self -- Sustaining Chain reactionSustaining Chain reaction

Neutron capture then neutron emission

Gamma Rays emission (Gamma Rays emission (γγ))Isomeric Transition Isomeric Transition

•• Some daughter nuclides produced by Some daughter nuclides produced by αα--decay or decay or ββ--decay are often obtained in an excited statedecay are often obtained in an excited state. The . The excess energy associated with this excited state is excess energy associated with this excited state is released when the nucleus released when the nucleus emits a photon in the emits a photon in the γγ--ray portionray portion of the electromagnetic spectrum.of the electromagnetic spectrum.

•• There are certain well defined ways in which There are certain well defined ways in which neutrons and protons may be arrangedneutrons and protons may be arranged within the within the nucleus. nucleus. In each configurationIn each configuration, a different amount , a different amount of energy is stored in the nucleus.of energy is stored in the nucleus.

•• The excited nucleus attains a more stable The excited nucleus attains a more stable configuration by gamma rays emission configuration by gamma rays emission ((γγ) ) carries carries neither charge nor mass.neither charge nor mass.

Gamma Rays emission (Cont.) Gamma Rays emission (Cont.)

•• The more excited (or upper isomeric state) is called The more excited (or upper isomeric state) is called metastable state or levelmetastable state or level which indicated by which indicated by ““mm”” written written after the mass numberafter the mass number (99mTc, 110mAg) and decay with (99mTc, 110mAg) and decay with different different short halfshort half-- liveslives from the non from the non -- metastable metastable nuclides:nuclides:

•• NuclideNuclide HalfHalf--lifelife•• 99 99 TcTc 2.1 x 102.1 x 1055 yearsyears•• 99m 99m TcTc 6 h6 h•• Nuclear isomersNuclear isomers: Nuclides with the same mass and atomic : Nuclides with the same mass and atomic

numbers but different halfnumbers but different half-- liveslives•• Isomeric transition:Isomeric transition: is the process by which a nuclide is the process by which a nuclide

decays to isomeric nuclide (one of the same Z and A) of decays to isomeric nuclide (one of the same Z and A) of lower quantum energylower quantum energy..

Production of radionuclidesProduction of radionuclidesArtificial Production of radionuclidesArtificial Production of radionuclides

Nuclear ReactorsNuclear Reactors CyclotronCyclotron-- Produced Produced IsotopesIsotopes GeneratorsGenerators

Artificial radionuclides are derived by either:

1- Bombardment of stable target nuclei with neutrons, usually in a nuclear reactor .

2- Bombardment of stable target nuclei with charged particles, usually in cyclotron.

3- Elution of the generator to produce short half life radionuclides.

1.1. Nuclear Reactors Nuclear Reactors (Nuclear piles)(Nuclear piles)

•• These are devices for producing high fluxes of neutrons. These are devices for producing high fluxes of neutrons. •• The neutrons in reactors are a mixture of:The neutrons in reactors are a mixture of:

••

Fast NeutronsFast Neutrons

High EnergyHigh EnergyThermal NeutronsThermal Neutrons

•• In the reactor the uranium fission reaction produces a In the reactor the uranium fission reaction produces a large supply of neutrons.large supply of neutrons.

•• One neutron for each uranium atom undergoing fission is One neutron for each uranium atom undergoing fission is used to sustain the reactionused to sustain the reaction..

• The remaining neutrons are used either to:1- Produce plutonium by interaction with 238U nuclei,2- Produce radioactive products by causing the neutrons to

interact with specific substances which have been inserted into the pile. (process is known as neutron process is known as neutron activation). activation).

Nuclear ReactorsNuclear Reactors• Thus, there are two sources of useful radioactive

substances from the pile:• (1) Those produced as fission products.• (2) Those produced by neutron activation.

II-- Production of radioactive Fission ProductsProduction of radioactive Fission Products• The following reactions illustrate one of many combinations of

fission reactionsfission reactions which are possible.• 238 1 131 106 1 1• U + n Sn + Mo + n + n• 92 0 50 42 0 0

The SnSn and the MoMo are very radioactive and have very short half-lives. They immediately decayimmediately decay by a series of beta decayprocesses

• 131 131 131 131• Sn Sb Te I• 50 51 52 53

AntemonyAntemony TeloriumTelorium

Nuclear Reactors (Cont.)Nuclear Reactors (Cont.)

• 106 106 106 106• Mo Tc Ru Rh• 42 43 44 45

Technetium RutheniumRhodium

*Both *Both IodineIodine and and RuRu are available commercially as fission producedare available commercially as fission producedisotopes. Before use, however, they isotopes. Before use, however, they must be separatedmust be separated chemically chemically from a large number of other fission from a large number of other fission --produced radioisotopes produced radioisotopes (costly(costly).. Hence, the majority of radioactive compounds are prepared Hence, the majority of radioactive compounds are prepared by neutron activationby neutron activation

IIII-- Production of radioactive compounds by Neutron Production of radioactive compounds by Neutron ActivationActivation

AA-- The Neutron Capture (n,The Neutron Capture (n,γγ) reaction (Thermal Neutrons)) reaction (Thermal Neutrons)

BB-- Transmutation process (n,p) reaction (Fast Neutrons)Transmutation process (n,p) reaction (Fast Neutrons)

AA-- The Neutron Capture (n,The Neutron Capture (n,γγ) reaction) reactionThis involves the This involves the capture of thermal neutronscapture of thermal neutrons by the by the

target nuclei to yield a radioactive compound target nuclei to yield a radioactive compound nucleus, which is in nucleus, which is in an excited statean excited state due to the due to the binding energy liberated by the capture of a neutron. binding energy liberated by the capture of a neutron. This surplus energy is emitted as gammaThis surplus energy is emitted as gamma-- radiationradiation

•• 23 1 24m 23 1 24m 2424•• Na + n Na Na + n Na NaNa + + γγ•• 11 0 11 11 0 11 1111

IIII-- Production of radioactive compounds by Production of radioactive compounds by Neutron ActivationNeutron Activation

The process usually does The process usually does not yield material of high specific not yield material of high specific activityactivity in some cases since the product is chemically identical in some cases since the product is chemically identical to the target and so cannot be separated from it easily to the target and so cannot be separated from it easily but high but high specific activity nuclides may be obtained in some cases, such aspecific activity nuclides may be obtained in some cases, such as 56Mn, s 56Mn, 192Ir, 198 Au192Ir, 198 Au

B- Transmutation process (n,p) reaction• These reactions involve the loss of heavy particles (P).

In these reactions protons or α- particles are emitted from the compound nucleus following neutron absorption.

• Fast neutrons may be required for these reactions to occur, since considerable energy is needed to expel the heavy particle.

• Examples of the use of these reactions in radionuclide production:

• 32 1 32 1• S + n P + P• 16 0 15 1 • Advantage: In such cases the product is chemically

different from the target and can be separated in very very high specific activityhigh specific activity.

IIII-- Production of radioactive compounds by Production of radioactive compounds by Neutron ActivationNeutron Activation

2. Cyclotron2. Cyclotron-- Produced IsotopesProduced Isotopes(Accelerator)(Accelerator)

•• The cyclotron and similar particle accelerators The cyclotron and similar particle accelerators can be used can be used only with charged particlesonly with charged particles such as such as electrons, protons, electrons, protons, deuteronsdeuterons, etc, because the operation of such machines , etc, because the operation of such machines depends upon: depends upon: the interaction of magnetic and/or the interaction of magnetic and/or electrostatic fields with the charge (either + or electrostatic fields with the charge (either + or --) of the ) of the particle undergoing accelerationparticle undergoing acceleration..

•• When the particles have been accelerated to a high When the particles have been accelerated to a high velocity, they are velocity, they are caused to strike a targetcaused to strike a target, containing the , containing the atoms to be bombardedatoms to be bombarded..

• in this way Sodium Na-22 can be produced by the interaction of high - velocity deuterons with magnesium.

• 24Mg + 2 D 22Na + 4α• Other medically important nuclides which have been

produced in a cyclotron by use of high-energy deuterons include 11C, 13N, 15O. Those which have been produced using high- energy alpha particles include 18F, 123I, 124I.

CyclotronCyclotron

Advantage: target material converted to different Advantage: target material converted to different elements producing carrier free radionuclide.elements producing carrier free radionuclide.

Target

magnetic and/or magnetic and/or electrostatic electrostatic fieldsfields

3. Generators "cows3. Generators "cows““Production of shortProduction of short-- half life half life

radiopharmaceuticalsradiopharmaceuticals•• Where clinical tests require that a radioisotope be Where clinical tests require that a radioisotope be

administered internally, it is advantageous to use an administered internally, it is advantageous to use an isotope with a short halfisotope with a short half--life to minimize the radiation life to minimize the radiation dose received by the patientdose received by the patient. One of the most . One of the most significant advances in radiopharmaceuticals is the use significant advances in radiopharmaceuticals is the use of generators for the production of short half of generators for the production of short half –– life life radiopharmaceuticals.radiopharmaceuticals.

•• Generators are either: Generators are either: ion exchange resinsion exchange resins or or alumina columnsalumina columns which which contain contain a parent radionuclidea parent radionuclide. With time, the . With time, the parent parent radionuclide decays to a radionuclide decays to a daughter radionuclide that is daughter radionuclide that is not specifically adsorbed on the columnnot specifically adsorbed on the column. The . The daughter daughter radionuclideradionuclide is eluted or milked from the column by is eluted or milked from the column by eluent such as sterile saline on daily baseseluent such as sterile saline on daily bases

GeneratorsGenerators•• Example:Example:•• technetium Techtechnetium Tech--99m99m, which is obtained from a , which is obtained from a

generator constructed of molybdenumgenerator constructed of molybdenum--9999 adsorbed to adsorbed to an alumina column. an alumina column.

•• MolybdenumMolybdenum--99 decays with 66 hour half99 decays with 66 hour half-- life to life to technetiumtechnetium--99m99m, and , and the technetiumthe technetium--99m is eluted (or 99m is eluted (or milked) from the column with normal salinemilked) from the column with normal saline solution. solution.

•• The 66 hour halfThe 66 hour half-- life of molybdenumlife of molybdenum--99 provides 99 provides sufficient manufacturing time for once weekly sufficient manufacturing time for once weekly preparation. Elution of the generator on a daily basis, preparation. Elution of the generator on a daily basis, by the by the nuclear pharmacistnuclear pharmacist, provides technetium , provides technetium -- 99 m 99 m for the preparation of radiopharmaceuticals.for the preparation of radiopharmaceuticals.

MolybdenumMolybdenum--99 Tec 99m eluted tech 99m99 Tec 99m eluted tech 99mFrom nuclear reactor From nuclear reactor 66hr66hr tt1/21/2 Saline tSaline t1/21/2 6hr6hr

Radioisotope parent-daughter Generator systems

Thyroid scanning2.3 h132 I3.2 day132Te(telorium)

Imaging of organs(diagnostic)6 hours99mTc66 h99Mo

(molybdenum)

Cancer therapy64 hours90Y(yttrium)28 y90Sr

ApplicationHalf-lifeDaughter isotope

Half-lifeParent isotope

GeneratorGenerator

ion exchange ion exchange resinsresins or or alumina alumina columns columns which which contain a parent contain a parent radionuclideradionuclide

The The daughter daughter radionuclideradionuclide is eluted is eluted or milked from the or milked from the column by eluent column by eluent such as sterile saline such as sterile saline on daily baseson daily bases

GeneratorGenerator

Best Wishes Best Wishes