Reivindicaciones
1. An iron oxide nanoparticle which comprises: a. A surface layer of a biodegradable hydrophilic polymer; and b. A core comprising an iron oxide and radionuclide suitable for medical imaging; wherein the nanoparticle ischaracterized by having the following values: a. r1 is from 3-10 mM<-1> s<-1> as measured by relaxometry, b. r2 is from 11-40 mM<-1> s<-1> as measured by relaxometry, c. a core size of from 1.5 - 3 nm as measured by Transmission Electron Microscopy (TEM), d. a hydrodynamic size of from 20 ± 5 nm according to dynamic light scattering measurement (DLS), and e. a superparamagnetic behavior with a value of magnetic saturation (Ms) of from 20 +/-10 as measured by a Superconducting Quantum Interference Device (SQUID). 2. The iron oxide nanoparticle of claim 1 wherein the radionuclide is selected from the list consisting of C-11, N-13, O-15, F-18, Cu-64, Ga-68, Ga-67, Tc-99, Ho-166, In-111, Lu-177, Yb-169, Bi-213, Er-169, Y-90 and T1-201 and Zr-89. 3. The iron oxide nanoparticle of any of claims 1 or 2 wherein the radionuclide is Ga-68 or Zr-89. 4. The iron oxide nanoparticle of any of claims 1-3, wherein the iron oxide is selected from the group consisting of FeO, Fe<3> O<4> , Fe<4> O<5> , Fe<2> O<3> or FeO<3> . 5. The iron oxide nanoparticle of any of claims 1-4 wherein the biodegradable hydrophilic polymer is dextran. 6. An iron oxide nanoparticle which comprises: a. A surface layer of dextran; and b. A core comprising an iron oxide selected from the group consisting of FeO, Fe<3> O<4> , Fe4O5, F2O3 or FeO3, and radionuclide selected from the group consisting of Ga-68 or Zr-89; wherein the nanoparticle ischaracterized by having the following values: a. r1 is from 3-10 mM<-1> s<-1> as measured by relaxometry, b. r2 is from 11-40 mM<-1> s<-1> as measured by relaxometry, c. a core size of from 1.5 - 3 nm as measured by Transmission Electron Microscopy (TEM), d. a hydrodynamic size of from 20 ± 5 nm according to dynamic light scattering measurement (DLS), and e. a superparamagnetic behavior with a value of magnetic saturation (Ms) of from 22 +/- 2 as measured by a Superconducting Quantum Interference Device (SQUID). 7. A preparation method of iron oxide nanoparticles comprising the following steps: a. Preparing a mixture in water or an alcohol selected from the group consisting of benzyl alcohol, ethanol, Isopropyl alcohol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, glycerol and octanol, having a pH between 8 and 12, comprising the combination of a. an iron salt, b. a radionuclide suitable for medical imaging, c. a biodegradable hydrophilic polymer, and d. a strong base in a sufficient amount for the mixture to have a pH between 8 and 12, b. Subjecting said mixture to fast ramping in less than three minutes to a temperature between 90 and 120°C with microwave irradiation at 220-300W for 3-11 min; and c. Purifying the nanoparticles obtained in step b). 8. The preparation method of iron oxide nanoparticles of claim 6 wherein the radionuclide is selected from the list consisting of C-11, N-13, O-15,F-18, Cu-64, Ga-68, Ga-67, Tc-99, Ho-166, In-111, Lu-177, Yb-169, Bi-213, Er-169, Y-90 and T1-201 and Zr-89. 9. The preparation method of iron oxide nanoparticles of any of claims 7 or 8, wherein the iron salt is selected from the group consisting of FeCl<3> , Fe(SO4), Fe<2> (SO4)<3> , Fe(NO<3> )<3> , FeCO<5> , Fe(OH)<2> and Fe(OH)<3> . 10. The preparation method of iron oxide nanoparticles of any of claims 7 -9, wherein the radionuclide is Ga-68 or Zr-89. 11. The preparation method of iron oxide nanoparticles of any of claims 7-10, wherein the mixture of step a) is subjected in step b) to fast ramping in less than one minute to about 100 °C with microwave irradiation at 220-240W for 8-11 min. 12. The preparation method of iron oxide nanoparticles of any of claims 7-10, wherein the mixture of step a) is subjected in step b) to fast ramping in less than one minute to about 100 °C with microwave irradiation at about 240W for about 10 min. 13. A nanoparticle as defined in any of claims 1-6 for use in therapy or medical diagnosis. 14. A nanoparticle as defined in any of claims 1-6 for use in a method of diagnosis and/or therapy capable of providing in vivo signals for PET (Positron Emission Tomography) and/or positive contrast MRI (Magnetic Resonance Imaging). 15. A nanoparticle as defined in any of claims 1-5 for use in a method of diagnosis and/or therapy via systemic administration, preferably intravenous administration, capable of providing in vivo signals for PET (Positron Emission Tomography) and/or positive contrast MRI (Magnetic Resonance Imaging).
