Patent Description:
Photo- and electro-disintegration of nuclei have been traditionally used for studying giant dipole resonances (GDR) and through them nuclear structure. More recently, through laser and smart material devices, electrons have been accelerated in condensed matter up to several tens of MeV. The possibility of inducing electro-disintegration of nuclei through such devices has been previously explored in [<NUM>], [<NUM>], and [<NUM>]. The methods involve a synthesis of electromagnetic and strong forces in condensed matter via giant dipole resonances to give an effective electro-strong interaction (ES), in the tens of MeV range. For a discussion of processes induced by electroweak reactions, see [<NUM>]. Applications of both electro-weak and electro-strong processes can be found in our two recent papers. [<NUM>], [<NUM>].

GDR are very well known across many disciplines beyond nuclear physics proper. For example, GDR mediate the energy at high nuclear energy due to dissociation within the cosmic microwave background. GDR are also well known to contribute in astrophysical nuclear synthesis. Prior to ES, Ejiri and Date [<NUM>] proposed Compton-backscattered laser photons from GeV electrons for the production of useful radioactive isotopes e.g. for medical applications via GDR. It has also been suggested that radioactive waste products such as <NUM> I could be transmuted via electron beam induced GDR and their subsequent decays, with transmutations to another isotope for safety. Some of these have been carried out at New SUBARU in Japan using <NUM> laser photons from a Nd:YVO laser, Compton scattered from a stored electron beam to energies up to <NUM> Me V. <NUM> I has been transmuted using a laser-generated plasma to accelerate electrons to produce gamma rays. These excite the GDR. For a very comprehensive review of laser-driven nuclear processes, see for example [<NUM>].

In light of the above discussion, GDR are very well understood and employed, both theoretically and practically in devices well outside the scope of nuclear physics proper.

Prior art methods for the production of medical radioactive isotopes can be found in patent documents <CIT> and <CIT>.

According to some aspects of the present invention, a novel method for generating radioactive isotopes is provided. These radioactive isotopes being used or needed either but not limited to the field of nuclear imaging or for cures in nuclear medicine. The inventors employ giant dipole resonances in nuclei based on a method and system based upon an efficient use of extensive theoretical and experimental work. Electron accelerators in hospitals dealing with nuclear medicine routinely generate the required photon beams can be suitable for the production of the isotopes and methods of this invention.

According to yet another aspect of the present invention, a method for producing radio-active isotopes using an electron machine via one-photon exchange by giant dipole resonances (GDR). Preferably, the method includes the steps of providing a stable copper (or fluorocarbon) isotope sample, and accelerating electrons by an electron accelerator to a peak photon energy of above <NUM> MeV to impinge on the stable copper (or fluorocarbon) isotope sample to generate a copper (or carbon and fluorine) radioisotope.

In this disclosure, a system for producing radioactive isotopes is provided. The system preferably includes an electron machine operable to perform one-photon exchange by giant dipole resonances (GDR), configured to accelerate electrons by an electron accelerator to a peak photon energy of above <NUM> MeV. The electron accelerator is configured to impinge the accelerated electrons onto for example a stable copper Cu isotope sample to generate a copper radioisotope or onto a piece of Teflon (C<NUM>F<NUM>)n to generate a carbon C or Fluorine F isotope.

According to one aspect of the present invention, the proposed method differs substantially from laser driven proposals discussed in the previous paragraph. Nuclear transmutation processes and experiments are proposed that utilize electro-strong (ES) interaction processes induced by the synthesis of electro-magnetic (EM) and strong forces for the production of radioisotopes (RI) needed for nuclear medicine. If the effective photon flux is approximately within <NUM><NUM>-<NUM> /sec. , then the expected rate of RI production would be about <NUM> <NUM>-<NUM>/sec. <NUM><NUM> Hz < Γisotope< <NUM><NUM> Hz corresponding to an RI density around (<NUM> - <NUM>) GBq/mg. <NUM>/mg< Γisotope< <NUM>/mg.

The above and other objects features and advantages to the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description with reference to the attached drawings showing some preferred embodiments of the invention.

The accompanying drawings, which constitute part of this specification, illustrate the presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain features of the invention.

<FIG> shows an exemplary Feynman diagram illustrating the production of RI according to an aspect of the present invention;.

<FIG> exemplarily shows the absorption rate of a photon y in Teflon (C<NUM>F<NUM>)n as a function of photon energy T;.

<FIG> exemplarily shows the Geiger counting rate in Hz for two radioactive samples Cu as a function of time in minutes after a the gamma ray beam created the radioisotopes by GDR absorption;.

<FIG> exemplarily shows a system <NUM> for producing medical radioactive isotopes using an electron accelerator <NUM> via a one-photon exchange into target nuclear giant dipole resonances (GDR) of a isotope sample;.

<FIG> exemplarily shows a graph of the activity of <NUM>Cu and <NUM>Cu as a function of time. The vertical line represents the moment when the electron beam has been switched off;.

<FIG> exemplarily shows a graph comparing theoretical vs measured total activity of Cu RI (in Bq) as a function of time;.

<FIG> exemplarily shows the spectrum of the first Teflon target sample after irradiation, and the annihilation peak (<NUM> keV) is clearly visible, and <FIG> shows exemplarily the spectrum of the second Teflon target after irradiation. The annihilation peak (<NUM> keV) is again very visible;.

<FIG> exemplarily shows a graph representing the zoomed spectrum of the first target (<NUM>) after irradiation (annihilation peak), and <FIG> exemplarily shows a graph representing the zoomed spectrum of the second target (<NUM>) after irradiation (annihilation peak);.

<FIG> exemplarily shows a graph with the decay data and at to the activity for the first Teflon sample, and <FIG> exemplarily shows a graph with the decay data and at to the activity for the second Teflon sample.

Herein, identical reference numerals are used, where possible, to designate identical elements that are common to the figures. Also, the images are simplified for illustration purposes and may not be depicted to scale.

Over several decades, virtual photons from electron scattering as well as Bremsstrahlung photons have been routinely used to cause nuclear photodisintegration via the generation of giant dipole resonances (GDR) in the intermediate state. The reactions studied extensively are with production of one or two neutrons such as <MAT> <MAT> where y* is the virtual photon from electron scattering and A* stands for the nuclear disintegration product. Of course, their counterpart nuclear breakup reactions and two neutron production reactions from real photons have also been of continuous interest and study.

Typically, GDR's are in the (<NUM>-<NUM>) MeV range for heavy nuclei and (<NUM>-<NUM>) MeV for light nuclei. <NUM> MeV < E < <NUM> MeV. Detailed experimental compendia [<NUM>] of GDR energies are available for a variety of applications.

In the above types of electron beam experiments, it is not simple to measure the amounts of transmuted nuclei since the recoil from the momentum hit of the gamma is at very low non-relativistic velocities. The transmuted nuclei thereby in dominant probability do not escape from the target. The object here is to provide the means for measuring the chemical concentrations within the target of the final nuclei. GDR produce neutron concentrations that are quite high in the range of about <NUM>-<NUM> to <NUM>-<NUM> <NUM><NUM> > xneutron> <NUM><NUM>per electron in the beam on thick targets.

With respect to endothermic fission and other transmutations, fission is usually considered for nuclei heavy compared with iron since the GRD are then on the low energy side of the binding curve. The light nuclei require a higher energy for fission disintegration. However, very little has been done in measuring the decay products of GDR fission in lighter nuclei beyond directly counting fast neutrons.

If tens of MeV are present in simple condensed matter systems and with the giant dipole resonances available, then endothermic fission reactions may be more interesting and more common than have been typically thought. Looking for new elements or new isotopes not present originally would indicate the occurrence of nuclear reactions in addition to the simple detection of neutrons many of which may be too slow to make it to detectors but which could reveal themselves through further transmutations. We emphasize that since the processes considered here, unlike earlier electroweak low energy nuclear reactions, are not suppressed by the Fermi constant, the scale at which transmutations occur could be very large. Weak decay rates may be of the order of a thousand times lower or maybe more than the electro-strong photodisintegration rates.

Of course one can also expect increased rates for exothermic fission reactions, such as increased rates of spontaneous nuclear fission processes. Whatever nuclei are produced, they may in turn undergo further reactions such as decays (weak or strong or through emission of gamma rays) and may absorb neutrons such as those produced in the initial GDR decay.

The herein presented method opens up a vast range of possibilities to consider with searches for new nuclei not originally present. These might be revealed via chemical means, neutron activation, electron microscopy elemental analysis, X-ray fluorescence, or other techniques. Specifically, if electrons are accelerated to tens of MeV in condensed matter systems, then one expects both endothermic and exothermic nuclear fission processes as well as the appearance of new nuclei due to further reactions of the decay products including further decays and/or the absorption of produced neutrons.

In references [<NUM>, <NUM>], we have discussed electro-strong (ES) induced endothermic fission that can take place in addition to the more common exothermic fission and alterations in exothermic fission rates as well as other transmutations that can occur in condensed matter systems. A particularly interesting experimental example is provided in [<NUM>] in which aluminum and silicon might appear in an initial sample of iron. According to an aspect of the present invention we find the following. If electrons are accelerated to several tens of MeV in condensed matter systems containing iron, then one may expect the appearance of aluminum and silicon.

With respect to the generation of nuclear isotopes for medicine, the ES interaction method or system discussed above can be generically used for a whole host of nuclear transmutations. We have verified by observing the decay products from medical radioisotopes of Copper, Carbon, and Fluorine. The medical radioisotopes were all produced employing a standard hospital electron accelerator yielding photon beams of approximately <NUM> MeV in energy to photo disintegrate otherwise stable nuclei in condensed matter targets.

<FIG> exemplarily shows the electron radiates a photon y into a nucleus having charge Z and atomic number A. The nucleus is excited into a giant dipole resonant state that disintegrates into a radioisotope with atomic number A-<NUM> plus a neutron n. As examples we have the photodisintegration of otherwise stable naturally occurring isotopes in pure copper into medically useful radioisotopes according to the reactions <MAT> <MAT> Similarly, we have the photodisintegration of otherwise stable naturally occurring isotopes in Teflon into medically useful radioisotopes of Carbon and Fluorine according to the reactions <MAT> <MAT> The photon absorption rate on Teflon in arbitrary units as a function of photon energy measured coming from a LINAC electron source is shown in the spectrum analyzer plot below in <FIG>.

In <FIG>, the absorption rates a photon y in Teflon (C<NUM>F<NUM>)n are exemplarily shown as a function of photon energy. The photon source was a medical LINAC and the first red line marks the known giant dipole resonance energy of <NUM> MeV in <NUM>C. The second higher energy red line broadly distributed around <NUM> MeV marks the giant dipole resonance in <NUM>F.

With respect to stable and unstable isotopes of copper, we recall here that <NUM>Cu and <NUM>Cu are the two naturally occurring stable isotopes of Copper:.

Production of RI <NUM>Cu via GDR: According to an aspect of the present invention, a method is proposed to produce the above RI using an electron machine via one-photon exchange GDR is schematically as follows: <MAT> <MAT>.

Only the stable A=<NUM> Cu and not the more abundant A-<NUM> Cu produces the desired A=<NUM> Cu medical isotope.

We have measured the above Cu reactions employing a standard Hospital electron accelerator yielding about a <NUM> MeV photon beam.

<FIG> shown the Geiger counting rate in Hz for two radioactive samples Cu as a function of time in minutes after a the gamma ray beam created the radioisotopes by GDR absorption. The known half-lives of the radioisotopes fit to the slopes of the curves to within a few percent of the known half-lives. The above counting curves may employed to estimate the long-lived medical radioactive isotope A= <NUM> Cu.

Spin parity considerations seem to favour this channel. The initial nuclear ground state of <NUM>Cu has JP= <NUM>/<NUM>- and the initial photon has JP = <NUM>-. The final state nuclear ground state <NUM>Cu has JP = <NUM>+ and the final neutron has JP = <NUM>/<NUM>+.

According to the compilation of GDR cross-sections on nuclei as discussed in reference [<NUM>], the parameters for the required process are as follows: <MAT>.

Taking the initial ~<NUM>/<NUM> concentration in copper yields a peak cross-section for the production of the Medical radioisotope of about <NUM> milli barn. A useful estimate of the number of Medical radioisotopes of Cu produced per electron of the LINAC may be found in [<NUM>]. On this basis we estimate the efficiency of the processes as ~ <NUM>-<NUM> Medical Cu per electron.

In sum, according to an aspect of the present invention, a novel and a relatively cheap generic method for generating radioisotopes of particular need in nuclear medicine is presented. The method does not employ nuclear reactors, lasers or neutron sources. Rather, use is made of commonly available hospital electron accelerators in those hospitals practicing nuclear medicine and it utilizes GDR and ES interactions. The particular case of the RI <NUM>Cu is presented in detail and shown to provide a local generation capability at a much-reduced cost and a fast in situ preparation.

Employing the same hospital LINAC as above to obtain a photon beam of <NUM> MeV impinging on a Teflon (C<NUM>F<NUM>) target, we observed simultaneous production of two medical radioisotopes <NUM>F and <NUM>C via the nuclear reactions y* + <NUM>F → n + <NUM>F; y* + <NUM>C
→ n + <NUM>C.

Given the expertise and knowledge of the underlying physical mechanisms, the Inventors are in a position to provide a pre-prepared closed kit, called Y[X]. The kit in the following is specially designed for the local production of a given RI, called X as follows:
While X is too short lived to be stored over a long period of time, the kit Y[X] can be stored for long periods as it would contain only stable parent nuclei and other substances needed to properly chemically enclose X after it has been produced.

A given hospital in possession of an electron accelerator, can purchase the kit Y[X] and store it in their labs. When the radio isotope X in its proper chemical ambience is required the kit Y[X] can be directly exposed to the beam and the radio isotope X, in its properly designed material environment can be produced ready for its employment with little or no loss of time.

According to an aspect of the invention, the kit Y[X] can be designed for specific use by the end user. For example, the end user in a hospital, e.g. technician, clinician or researcher, may obtain a given amount of <NUM>CuCl<NUM> <NUM>CuCl<NUM> to inject into a subject. Clearly other chemical preparations presently in use may be employed.

This chemical isotope may be used either as a tracer or as a therapeutic tool. The chosen amount of the chemical corresponds to a given level of radiation emitted by the radionuclide that the user wants for a specific imaging application. The production mechanism described in the present patent application to estimate the electron beam configuration, for example but not limited to the beam energy, the scattering angle, the intensity, the amount and dimensions of the material, necessary to produce the prescribed amount of the radio nuclide from naturally occurring Copper. Similar statements may be made for medical Carbon and Fluorine medical isotopes that may employed for positron PET scans.

The kit would provide a stable Copper or Teflon sample of dimensions suitable for the purpose along with prescriptions, e.g. for the amount of beam time for electron irradiation and other information to produce required amounts of radionuclide.

Once the radio nuclide is produced in loco, the user would have to follow the usual procedures to separate it from the rest of the material, pass it through an HCl solution for example, and save it say as a radioactive salt for further use.

<FIG> shows an exemplary implementation of the method or the system <NUM> according to an aspect of the present invention, showing an electron accelerator <NUM>, a controller <NUM> for controlling the operation of the electron accelerator <NUM>, for example a personal computer or other type of data processing device, or a data processing and controlling equipment that is an integral part of the electron accelerator <NUM>, an electron beam applicator <NUM>, an electron beam <NUM>, an isotope sample plate <NUM> that can be placed into the electron beam <NUM>, for example but not limited to a copper plate <NUM>, treatment couch <NUM>, for example but not limited to a carbon fiber treatment couch.

With the system <NUM> that is exemplarily shown in <FIG>, experimental data from the medical oncology department of a Swiss hospital has shown the operation of the method by the production of radio nuclides <NUM>Cu and/or <NUM>Cu when a sample of pure Copper was irradiated by a beam of <NUM> MeV photons from the electron accelerator facility in the oncology department of the Cantonal Hospital of Fribourg in Switzerland (Hôpital Cantonal Fribourgeois "HFR"). Evidence of the RI production is provided through the measurements of the radiation from the two Copper radio nuclides and the two measured life-times are within <NUM>% of their expected values. Also presented are experimental results about the production of the much sought after radionuclide <NUM>F along with another <NUM>C in one shot, through a non-cyclotron or a nuclear reactor source.

The system for the generation of copper radio nuclides was included the following elements and arrangements: A <NUM> to <NUM> Copper (Cu) plate <NUM> with a thickness of <NUM> was placed under a broad electron beam <NUM> (at <NUM> MeV) from an electrode accelerator, for example a TrueBeam <NUM>. 7MR2 Linear Accelerator from Varian. The Copper plate <NUM> was centered in the beam that produced through a <NUM> to <NUM> applicator <NUM>. The copper plate <NUM> was placed at a source-surface distance (SSD) of <NUM>. The plate <NUM> lay on the treatment couch <NUM> that was made of carbon fiber to reduce any other contribution to the measured activation. A maximum dose rate (<NUM> Monitor Units / min = <NUM> MU/min) was chosen by controller <NUM>, corresponding to <NUM> Gy/min at <NUM> SSD. Then the Copper plate <NUM> as a target was irradiated for <NUM> minutes thus totaling <NUM>,<NUM> MU. As soon as the beam was stopped (after <NUM>,<NUM> MU) by controller <NUM>, the chronometer was started to measure the activity and radiation expected from the production and decays of radio nuclides Cu<NUM> and Cu<NUM>. The detector used was a NaI(Tl) <NUM>" × <NUM>" (<NUM> × <NUM>) crystal gamma-scintillation detector.

For the method and system for the generation of RI <NUM>F and <NUM>C using Teflon (C<NUM>F<NUM>) targets are as follows: Two sets of measurements were made with Teflon. A first Teflon sample weighing <NUM>:<NUM>(<NUM>) gms was irradiated with <NUM>,<NUM> MU of the <NUM> MeV electron beam. To alleviate excessive intensity of the source and the dead time of our detector, a second Teflon weighing <NUM> gms was irradiated with only <NUM>,<NUM> MU by the same electron beam. For both Teflon experimental tests, the method included a step of placing the target in front of the detector for twenty-four (<NUM>) hours after having stopped the short irradiation. Zero time is the time when the beam stopped. A few minutes later the measurement started taking into account this zero time (starting point of the time scale). The software PRA. exe accumulated all the events with the time of appearance. Thus, after the measurement, it was feasible to analyze the spectrum (from <NUM> to <NUM> MeV) by focusing on a single part. Clearly the interesting part for both isotopes <NUM>C and <NUM>F lies in the annihilation peak area (<NUM> keV). Each Teflon target was irradiated at <NUM>,<NUM> MU/minute under the broad beam of <NUM> MeV electrons (Applicator <NUM> × <NUM>). A short time (~ <NUM> minutes) later, they were deposed in front of the detector for twenty-four (<NUM>) hours one after the other.

<FIG> shows the measured radiation activity in units of number of counts/min as a function of time, providing for evidence of the production of <NUM>Cu and <NUM>Cu radio nuclides. In the upper section of <FIG> data us shown for early times (up to <NUM> minutes) and in the lower section of <FIG> the same data are shown over the complete period of measurement (<NUM> minutes). A fit was performed and the following half-lives for <NUM>Cu and <NUM>Cu were determined from the activity curves. <MAT> Experimental value: <NUM> minutes: <MAT> Experimental value: <NUM> minutes:.

Clearly, there is more than satisfactory agreement between the data and theoretical expectations about the production of copper nuclides through the method proposed. For the generation of <NUM>F and <NUM>C, a small sample of Teflon was irradiated by the photon beam as described above. Clear signals for the production of both radio nuclei are shown in <FIG>. The life times are in very good agreement with their known values:.

As explained above, these results achieved confirm that electron accelerators commonly available at medical oncology centers around the world, can be used to produce the required amounts of radio nuclei in situ locally, when needed. It can therefore reduce the cost of production as well as that of transport and at the same time avoid the use of nuclear reactors or cyclotrons that can suffer from the unwanted production of nuclear waste. The copper plates <NUM> can be used repeatedly since both produced copper radio nuclides have a shelf life of only a few days. Thus, ordinary storage of copper plates <NUM> would be adequate and should require no special handling.

Next, different methods are described for the generation of radio isotopes. For example, a first method for giant dipole resonance (GDR) method is described for <NUM>Cu, <NUM>Cu production. As further discussed below, <NUM>Cu and <NUM>Cu are the two naturally occurring stable isotopes of Copper and the short half-life isotope <NUM>Cu is one of the radio-isotopes wanted in nuclear medicine both for imaging and for treatment of cancer, due to its decays both via β +(<NUM>% into <NUM>Ni) and β -(<NUM>% into <NUM>Zn) modes and producing only benign elements such as Nickel and Zinc.

With respect to the production of RI <NUM>Cu via GDR, the first method for producing this RI using an electron machine via one photon exchange GDR process producing a single neutron is schematically as follows: <MAT> <MAT> <MAT>.

It can be seen that only the stable A = <NUM> Copper (and not the other, more than twice more abundant A = <NUM> Copper) can produce the wanted radio isotope A = <NUM> along with a single neutron. Spin parity considerations seem to favor this channel. The initial nuclear ground state of <NUM>Cu has JP = <NUM>/<NUM>- and the initial photon has JP = <NUM>+. The final state nuclear ground state <NUM>Cu has JP = <NUM>+ and the final neutron has JP = <NUM>=<NUM>+. According to the compilation of GDR cross-sections on nuclei[<NUM>], the parameters for the required process are as follows: <MAT> Peak photon energy Eγ(peak) ~ <NUM>MeV;
Cross - section at the peak :
σ(max) ~ <NUM> milli - barns.

Of course, the above cross-section should be multiplied by <NUM>: <NUM> for the measurable cross-section since a given piece of Copper has only <NUM>% of <NUM>Cu in it. Thus, approximately <NUM> milli-barns may be expected as the peak cross-section for producing <NUM>Cu nucleus. Very useful estimates of the number of neutrons produced per electron in the initial electron-energy interval of interest here (<NUM> ÷ <NUM>) MeV, see reference [<NUM>]. Roughly speaking, for a Copper target of thickness between (<NUM> ÷ <NUM>) radiation lengths [corresponding to the material thickness (<NUM> ÷ <NUM>) gm. /cm<NUM>, the number of neutrons/electron ranges between (<NUM> ÷ <NUM>) × <NUM>-<NUM> for an incident electron energy of about ~ <NUM> MeV. To within a factor of two, we should expect the same ratio for the number of <NUM>Cu produced per electron of about <NUM> MeV.

Next, the production of RI 62Cu via GDR is described. There is a shorter lived radio isotope of Copper <NUM>Cu that can be GDR produced along with a neutron by <NUM>Cu:.

Its [<NUM>% decay] into positrons renders this RI as an excellent candidate for imaging and relabeling of molecules, whereas its almost total disappearance within less than an hour, renders Cu<NUM> of less practical and more restricted use for treatment than Cu<NUM>.

Next, a second GDR method for <NUM>Cu and <NUM>Cu production is described. The goal is to is to find stable isotopes of an element with a certain charge (Zparent) that can produce the sought for radio nuclide(s) of charge (Zdaughter ≠ Zparent) different from that of the parent nucleus, by the use of the GDR mechanism. Of course, since ΔZ ≠ <NUM>, the rest of the final state would have to have a non-vanishing charge and thus cannot be a single neutron. While this implies a reduction in the nuclide production cross-section, it has the distinct advantage that expensive isotope separations would not be required. With suitable amounts of extra parent material, higher electron luminosity and increased bombardment time, the problem of reduction in the cross-section can be largely circumvented. Let us apply the above towards producing Copper radio nuclides (charge Z = <NUM>) through the bombardment of a parent nucleus Zinc (charge Z = <NUM>). There are the following four (<NUM>) stable isotopes of Zinc of relevance here:.

For the purpose at hand, let us consider the following GDR-induced final state reactions. <MAT> <MAT> <MAT> <MAT> <MAT>.

The production of the nucli <NUM>Cu through the proton mode as well as the production of nuclides <NUM>Cu and <NUM>Cu, via both the deuteron and the (np) modes have been measured. It was found that the deuteron production in the threshold region is anomalously "large. " At <NUM> MeV, the production cross-section for the nuclide <NUM>Cu from Zinc, as shown in the equation above, is <NUM> milli-barns. On the other hand, at similar energies, the peak production cross-sections for the nuclides <NUM>Cu, <NUM>Cu through the d and (np) modes, are about three (<NUM>) milli-barns, a factor of about six (<NUM>) smaller. However, folding in the natural concentrations of the various Zinc isotopes, the effective production cross-sections of <NUM>Cu:<NUM>Cu:<NUM>Cu should be roughly (<NUM>:<NUM>:<NUM>:<NUM>:<NUM>:<NUM>) milli-barns, respectively. For proton associated photo-production of <NUM>Cu, see[<NUM>] for further details. A chemical separation of the produced Copper nuclides from Zinc was already performed in reference [<NUM>] quite successfully. The details can be found in Appendix of reference [<NUM>]. Presently, more modern chemical methods can be employed for this purpose, see reference [<NUM>], [<NUM>].

Next, the simultaneous electro-production of <NUM>F and <NUM>C radio-nuclides are described, as discussed above. As a proof of concept experiment for the production of another much sought after tracer radio nuclide, the production of <NUM>F using an electron accelerator has been investigated. As can be seen from the following discussion, we use a solid target in contrast to an aqueous solution used routinely. In the detailed review published by International Atomic Energy Agency, Vienna, Austria (IAEA) of <NUM>, regarding the medical applications of radio nuclides, it is stated that the present medical demand for <NUM>F far exceeds its availability [<NUM>]. Therefore, this alternative embodiment for the method is useful as we can produce it in tandem with another medically important radio isotope <NUM>C. Let us recall some well-known facts about stable fluorine and its one isotope relevant for medicine:.

Due to its fast decay rate, the "shelf life" of <NUM>F, limited to two half-lives, is only about four (<NUM>) hours and distribution of such radio isotopes presents logistic problems. It is for this reason that IAEA recommended establishment of centralized production facilities. This <NUM>-report stated the following: "the possibility of large scale production of radio isotopes from photons seemed very unlikely a decade ago, while now that possibility seems, at least at the proof-of-concept level, highly probable", see reference [<NUM>].

Given the technical advances made in the decade after the above report was published, according to an aspect of the present invention, a method is proposed to establish and equip radiation oncology departments towards in situ production of short-lived radio nuclides employing their in-house electron accelerators, suitably modified for this purpose. Different <NUM>F production mechanisms have been used. The two major nuclear reaction processes invoked for this purpose are the following: <MAT> <MAT>.

While the proton-initiated process has a larger cross-section, it requires "enriched" water (H<NUM><NUM> O) that is cumbersome and expensive, as the latter constitutes only approximately <NUM>% of ordinary water (H<NUM><NUM> O). Moreover, fluorine in the aqueous state generated via process (i) as referred to the above equation must be de-solvated & activated by treatment with a chelator, for example Kryptfix <NUM>. <NUM>, to bind the potassium and "free" the fluoride ions for direct nucleophilic labeling reactions. Process (ii) on the other hand, produces [<NUM>F]F<NUM> that can be directly used for electrophilic labeling.

It should also be noted that any hadronic initiated radio nuclide production process or method, for example initiated by a proton or a deuteron beam, can give rise to unwanted radio nuclides if the target has contamination from heavier materials. For example, a production of an undesired radio isotope <NUM>Co (half-life <NUM> hours) has been shown [<NUM>] due to the presence of iron in an aluminum foil target (Al<NUM> <NUM>O<NUM>) that was irradiated by a proton beam.

The GDR process for the production of <NUM>F that has been extensively experimented and discussed herein, and being an aspect of the present invention, is to irradiate polytetrauoroethylene [(C<NUM>F<NUM>)n], commonly known under the trade name Teflon, by an electron beam. There are <NUM> fluorine atoms for each carbon atom, by weight about <NUM>% fluorine and <NUM>% carbon and the substance is rather light (density = <NUM> gm / cm<NUM>). The chosen target material has the great advantage of not only producing <NUM>F (from the parent <NUM>F) but also <NUM>C from its parent <NUM>C.

As both produced radio nuclides are of medical imaging interest, this reaction is unique in this respect and offers a distinct advantage over previous methods. Next, a method is described for analyzing three (<NUM>) plates, that potentially can serve as an isotope sample plate <NUM> for the system <NUM>, where the plates are made of unknown materials. The goal is to find the materials inside of the three (<NUM>) plates using the NaI detector. Each of the three (<NUM>) unknown plates are placed in front of the detector, for example electron accelerator <NUM>, during twenty-four (<NUM>) hours one after the other. From experience of measurement without anything in front of the detector, one can say that this probe does not include contaminated material other that the normal (natural) background. Then each of the unknown plates (<NUM>, <NUM> and <NUM>) are irradiated for ten (<NUM>) minutes under a broad beam of 22MeV electrons using an applicator 15x15 with <NUM> MU. Thereafter they were disposed in front of the detector during twenty-four (<NUM>) hours one after the other. The strategy chosen was to concentrate on that annihilation peak and zooming on it evaluate the time dependency of events coming in that special portion of the spectrum.

The counts (and associated error) during one minute were taken for the whole range of <NUM> hours and just divided by <NUM> to get counts per second [s-<NUM>]. The fitted function for activity is expressed by the following equation: <MAT>.

As one can see in the previous equation : two different decays (A and B) were used for each plate and the background was also introduced in the fit (parameter : bck). Next, six (<NUM>) tables are presented that show the course of the fit for each plate and the results of the fit for each plate.

It has been observed that that plate <NUM> and <NUM> are very similar and present data compatible with a produced decay of a mix of <NUM>O (T½ : <NUM>) and <NUM>C (T½ : <NUM>). The plate <NUM> is different and as we fitted also two components. Perhaps it would have been better to take three components but statistics was insufficient to justify this. Plate <NUM> shows the <NUM>C (T½ : <NUM>) and <NUM>F (T½ : <NUM>).

Claim 1:
A method for producing medical radioactive isotopes using an oncology department in-house electron accelerator via a one-photon exchange into target nuclear giant dipole resonances (GDR), the method comprising the steps of:
providing an isotope sample from at least one from the list selected from a stable copper isotope sample, a carbon isotope sample, and a fluorine isotope sample;
accelerating electrons by the oncology department in-house electron accelerator to a peak photon energy of above <NUM> MeV to impinge on the isotope sample for a time period of <NUM> or <NUM> minutes to generate a copper radioisotope, a carbon radioisotope, or a fluorine radioisotope; and
using the copper radioisotope, the carbon radioisotope, or fluorine radioisotope as a radio-tracer for positron emission tomography (PET).