COMPOSITIONS AND METHODS FOR USE IN ONCOLOGY

Abstract

The present invention relates to compositions and methods for use in medical diagnosis and patient monitoring, typically in the context of therapy, in particular in the context of oncology, to optimize tumor bed local irradiation. It more particularly relates to a biocompatible gel comprising nanoparticle and/or nanoparticle aggregates, wherein: i) the density of each nanoparticle and of each nanoparticle aggregate is at least 7 g/cm.sup.3, the nanoparticle or nanoparticles of the aggregate comprising an inorganic material comprising at least one metal element having an atomic number Z of at least 25, more preferably of at least 40, each of said nanoparticle and nanoparticle aggregate being covered with a biocompatible coating; ii) the nanoparticles' and/or nanoparticle aggregates' concentration is of at least about 1% (w/w); and iii) the apparent viscosity at 2 s.sup.1 of the gel comprising nanoparticles and/or nanoparticle aggregates is between about 0.1 Pa.Math.s and about 1000 Pa.Math.s when measured between 20 C. and 37 C.

Claims

1. A biocompatible gel comprising nanoparticles and/or nanoparticle aggregates, wherein i) the density of each nanoparticle and nanoparticles aggregate is of at least 7 g/cm.sup.3, the nanoparticle or nanoparticles of the aggregate comprising an inorganic material comprising at least one metal element having an atomic number Z of at least 40, each of said nanoparticle and of said nanoparticle aggregate being covered with a biocompatible coating; ii) the nanoparticles and/or nanoparticle aggregate concentration is of at least about 1% (w/w); and iii) the apparent viscosity at 2 s.sup.1 of the gel comprising nanoparticles and/or nanoparticles aggregate, is between about 0.1 Pa.Math.s and about 1000 Pa.Math.s when measured between 20 C. and 37 C.

2. The biocompatible gel according to claim 1, wherein the nanoparticles and/or nanoparticle aggregate concentration is between about 1.5% and 10% (w/w).

3. The biocompatible gel according to claim 1, wherein the inorganic material is a metal, an oxide, a sulfide, or any mixture thereof.

4. The biocompatible gel according to claim 1, wherein the nanoparticle or nanoparticle aggregate further comprises at least one targeting agent.

5. The biocompatible gel according to claim 1, wherein the gel is a hydrogel.

6. The biocompatible gel according to claim 1, wherein, when the gel is applied on a target biological tissue, nanoparticles and/or nanoparticle aggregates of the biocompatible gel allow an at least about 10% increase of the radiation dose deposited on said target biological tissue when exposed to ionizing radiation, as compared to the radiation dose deposited on the same biological tissue in the absence of said gel.

7. The biocompatible gel according to claim 6, wherein the applied ionizing radiation dose is between 2 KeV and 25 MeV.

8. The biocompatible gel according to claim 7, wherein the ionizing radiation is selected from X-rays, gamma rays or electron beam.

9. The biocompatible gel according to claim 6, wherein the gel allows the delineation and visualization of at least 40% of the target biological tissue.

10. The biocompatible gel according to claim 1, wherein the biological tissue is a tumor bed.

11. The biocompatible gel according to claim 10, wherein the tumor bed is the tissue covering the cavity obtained following tumor resection.

12. A kit comprising a biocompatible gel comprising nanoparticles and/or nanoparticle aggregates according to claim 1, wherein the biocompatible gel and the nanoparticles and/or nanoparticle aggregates are in distinct containers.

13. A method of delineating a tumor bed in a subject comprising depositing a biocompatible gel according to claim 1 onto the tumor bed and visualizing nanoparticles and/or nanoparticle aggregates to delineate the tumor bed.

14. The method according to claim 13, wherein the nanoparticles and/or nanoparticle aggregates are visualized by X-ray imaging equipment.

15. The method according to claim 13, wherein the biocompatible gel is deposited onto the tumor bed at the time of surgery.

16. The method according to claim 13, wherein the nanoparticles and/or nanoparticle aggregates are visualized between 24 hours and less than 1 month, between 24 hours and 3 weeks, or between 24 hours and 2 weeks following deposition onto the tumor bed.

17. A method of treating cancer comprising exposing the tumor bed of a subject to a biocompatible gel comprising the nanoparticles or nanoparticle aggregates according to claim 1 and irradiating said nanoparticles or nanoparticle aggregates using ionizing radiation beam(s), thereby treating the subject.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0113] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication, with color drawing(s), will be provided by the Office upon request and payment of the necessary fee.

[0114] FIG. 1: Tumor tissue delineation using clips

[0115] From Improving the definition of the tumor bed boost with the use of surgical clips and image registration in breast cancer patients (Int. J Radiation Oncology Biol. Phys. Vol 78(5): 1352-1355 (2010)). Tumor bed volume delineation: gross tumor volume (GTV) (red); clinical target volume (CTV) clips=all clips with 0.5-cm margins; planning target volume (PTV) (green)=GTV+CTV clips+0.5-cm lateral and 1-cm superior-inferior margins.

[0116] FIG. 2: Micro-CT (CT) images captured 2 days, 8 days and 20 days after gel deposition into the cavity obtained following tumorectomy, showing the tumor bed delineation using a biocompatible hydrogel according to the invention, composed of methylcellulose (5% w/w) comprising biocompatible nanoparticles and/or nanoparticle aggregates (3.5% w/w) consisting of hafnium oxide. The nanoparticles and/or nanoparticle aggregates have been mixed with the gel prior to gel deposition into the tumor bed.

[0117] FIG. 3: CT images captured 2 days, 9 days and 20 days after gel deposition into the cavity obtained following tumorectomy, showing the tumor bed delineation using a biocompatible hydrogel according to the invention, composed of methylcellulose (9% w/w) comprising biocompatible nanoparticles and/or nanoparticle aggregates (3.5% w/w) consisting of hafnium oxide. The nanoparticles and/or nanoparticle aggregates have been mixed with the gel prior to gel deposition into the tumor bed.

[0118] FIG. 4: Effect of particle concentration on radiation dose enhancement using Monte Carlo calculation.

[0119] FIG. 5: Viscosity measurement (A at 20 C. and B at 37 C.) of a gel composed of hyaluronic acid (3% w/w) and a gel composed of hyaluronic acid (3% w/w) comprising biocompatible nanoparticles and/or nanoparticle aggregates (5% w/w) consisting of hafnium oxide.

[0120] FIG. 6: FTIR spectrum of a gel composed of hyaluronic acid (0.1% w/w) comprising biocompatible nanoparticles and/or nanoparticle aggregates (0.26% w/w) consisting of hafnium oxide. Comparison with the spectrum of the gel composed of hyaluronic acid and also with the spectrum of nanoparticles and/or nanoparticle aggregates consisting of hafnium oxide.

[0121] FIG. 7: CT images captured 30 minutes (D01), 1 day (D02), 3 days (D04), 8 days (D09) and 22 days (D23) after gel deposition into the cavity obtained following tumorectomy, showing the tumor bed delineation using a biocompatible hydrogel according to the invention. The gel is composed of hyaluronic acid (3.8% w/w), hyaluronic acid (2.5% w/w) and auto-cross-linked hyaluronic acid (3% w/w) comprising biocompatible nanoparticles and/or nanoparticle aggregates (5% w/w) consisting of hafnium oxide. The nanoparticles and/or nanoparticle aggregates have been mixed with the gel prior to gel deposition into the tumor bed.

EXAMPLES

Example 1: Biocompatible Hafnium Oxide (HfO.SUB.2.) Nanoparticles or Nanoparticle Aggregates, Using Sodium Hexametaphosphate as Coating Agent

[0122] A tetramethylammonium hydroxide (TMAOH) solution is added to HfCl.sub.4 solution. Addition of TMAOH solution is performed until the pH of the final suspension reaches a pH comprised between 7 and 13. A white precipitate is obtained.

[0123] The precipitate is further transferred in an autoclave and heated at a temperature comprised between 120 C. and 300 C. to perform crystallization. After cooling, the suspension is washed with de-ionized water.

[0124] Sodium hexametaphosphate solution is then added to the washed suspension and the pH is adjusted to a pH comprised between 6 and 8.

[0125] Sterilization of the nanoparticle or nanoparticle aggregate suspension is performed prior to in vitro or in vivo experiments.

Example 2: Synthesis and Physico-Chemical Characterisation of Gold Nanoparticles with Different Sizes

[0126] Gold nanoparticles are obtained by reduction of gold chloride with sodium citrate in aqueous solution. Protocol was adapted from G. Frens, Nature Physical Science 241 (1973) 21.

[0127] In a typical experiment, HAuCl.sub.4 solution is heated to boiling. Subsequently, sodium citrate solution is added. The resulting solution is maintained under boiling for an additional period of 5 minutes.

[0128] The nanoparticles' size is adjusted from 15 nm to 105 nm by carefully modifying the citrate versus gold precursor ratio (see Table 1).

[0129] The as-prepared gold nanoparticles' suspensions are then concentrated using an ultrafiltration device with a 30 kDa cellulose membrane.

[0130] The resulting suspensions are ultimately filtered through a 0.22 m cutoff membrane filter under a laminar hood and stored at 4 C.

[0131] Particle size is determined on more than 200 particles, by using Transmission Electronic Microscopy (TEM) and by considering the longest nanoparticle dimension of each particle.

TABLE-US-00001 TABLE 1 Synthesis Samples Particle size (nm) Citrate HAuCl.sub.4 Gold-15 15 2 (1) 20 mL 30 mL 500 mL 0.25 mM Gold-30 32 10 (1) 7.5 mL 40 mM 500 mL 0.25 mM Gold-60 60 10 (1) 2 mL 85 mM 500 mL 0.25 mM Gold-80 80 10 (1) 1.2 mL 43 mM 200 mL 0.30 mM Gold-105 105 25 (1) 1.2 mL 39 mM 200 mL 0.33 mM

Example 3: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (3.5% w/w) within the Gel (Methylcellulose 5% w/w) Prior to Gel Deposition on the Tumor Bed

[0132] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1 is added to a volume of gel, typically with a polymer (methylcellulose) concentration lying between 4.5% w/w and 5.5% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel is adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 3.5% (w/w). The preparation thus obtained is typically mixed with a magnetic stirrer or a spatula.

Example 4: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (3.5% w/w) within the Gel (Methylcellulose 9% w/w) Prior to Gel Deposition on the Tumor Bed

[0133] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1, is added to a volume of gel, typically with a polymer (methylcellulose) concentration lying between 8.5% w/w and 9.5% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel being adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 3.5% (w/w).

Example 5: Assessment by Micro-Computed Tomography (CT) of the Quality of the Tumor Bed Delineation Obtained when Using Nanoparticles Embedded in Hydrogel from Example 3

[0134] The objective of this experiment was to assess, by CT (Micro-Computed Tomography), the quality of tumor bed delineation by nanoparticles (NPs).

[0135] The test gel from example 3 was implanted (deposited) into the cavity left by the resection of HCT 116 xenografted tumors (human colorectal carcinoma cancer cells) in nude mice.

[0136] The CT analysis was performed 2 days, 8 days and 20 days following gel implantation into the cavity left by the resection of the tumor in order to evaluate the volume occupied by the nanoparticles and/or nanoparticle aggregates in the tumor bed over time. For this, a manual segmentation (region of interest (ROI)) was performed around the surgical cavity. Then a thresholding above 120 HU was performed inside the surgical cavity in order to evaluate the presence of nanoparticles or nanoparticle aggregates and to assess both the location and volume occupied by those nanoparticles or nanoparticle aggregates for all mice. FIG. 2 presents the CT images showing more than about 80% of cavity delineation as soon as 2 days following surgery and gel implantation.

Example 6: Assessment by Computed Tomography (CT) of the Quality of Tumor Bed Delineation Obtained when Using Nanoparticles Embedded in Hydrogel from Example 4

[0137] The objective of this experiment was to assess, by CT (Computed Tomography), the quality of tumor bed delineation by nanoparticles (NPs).

[0138] The test gel from example 4 was implanted (deposited) into the cavity left by the resection of HCT 116 xenografted tumors (human colorectal carcinoma cancer cells) in nude mice.

[0139] The CT analysis was performed 2 days, 9 days and 20 days following gel implantation into the cavity left by the resection of the tumor in order to evaluate the volume occupied by the nanoparticles and/or nanoparticle aggregates in the tumor bed over time. For this, a manual segmentation (region of interest (ROI)) was performed around the surgical cavity. Then a thresholding above 120 HU was performed inside the surgical cavity in order to evaluate the presence of nanoparticles or nanoparticle aggregates and to assess both the location and volume occupied by those nanoparticles or nanoparticle aggregates for all mice. FIG. 3 presents the CT images showing more than about 80% of cavity delineation as soon as 9 days following surgery and gel implantation.

[0140] Of note, gels comprising nanoparticles or nanoparticle aggregates prepared according to the protocols appearing in examples 3 and 4 have viscosity values at 2 s.sup.1 which are respectively equal to 190 Pa.Math.s and 720 Pa.Math.s at 37 C. Following their release from gels, the deposition of nanoparticles and/or nanoparticle aggregates on the tumor bed typically occurs within 2 days and 9 days, respectively (see FIGS. 2 and 3).

Example 7: Calculation of the Radiation Dose Deposit Increase when Nanoparticles and/or Nanoparticle Aggregates are Present on the Tumor Bed from the Estimation of Nanoparticles' or Nanoparticle Aggregates' Mean Concentration on the Tumor Bed

[0141] Table 2 presents calculated concentrations of any nanoparticles or nanoparticle aggregates as mentioned in claim 1 when the particles delineate the tumor bed. The initial concentrations of nanoparticles or nanoparticle aggregates within the gel were chosen at 1% (w/w) and 3.5% (w/w). The tumor bed volume was calculated assuming different diameters of tumor bed, said diameters being between 1 cm and 9 cm, while taking into account the diameter of the excised tumor as well as macroscopic margins. The thickness of the layers formed by deposition of the nanoparticles on the tumor bed was assumed to be respectively equal to 0.1, 0.5, 1 and 2 mm. The calculated nanoparticles or nanoparticle concentrations in those layers (nanoparticle concentration in the rimsee Table 2) above 100 g/l are underlined in bold characters.

[0142] FIG. 4 shows the effect of particle concentration on radiation dose enhancement using Monte Carlo calculation.

[0143] Radiation dose enhancement was performed using a global model calculation and a 6-MeV photon beam for both tumors with deep anatomical localization (with nanoparticles as mentioned in claim 1 composed of hafnium oxide, herein identified as NBTXR3 nanoparticles) and normal tissues (without nanoparticles). A Z.sub.global was used for the calculation.

[0144] In the global model calculation, the radiation dose enhancement (defined as the dose deposition in the tumor with high Z nanoparticles divided by dose deposition in the tumor without nanoparticles) results from energy deposition when considering an averaged Z value (Z.sub.global) equal to

Z.sub.global=(100x)Z.sub.water+xZ.sub.nanoparticles,

where x represents the concentration of nanoparticles within the tumor (mass of nanoparticles divided by the mass of the tumor), Z.sub.water represents the effective atomic number of water and Z.sub.nanoparticles represents the effective atomic number of the nanoparticles (i.e., hafnium oxide nanoparticles). In the calculation, the tumor was considered as having an effective atomic number equal to that of water. The nanoparticles increased the average efficacy of X-ray absorption in an isotropic fashion.

[0145] Results from FIG. 4 show that a 10% increase of radiation dose deposit is obtained for a nanoparticle concentration within the tumor equal to or above 10% (wt %).

[0146] Based on results from FIG. 4 of Nanoscale Radiotherapy with Hafnium Oxide Nanoparticles (Future Oncology 8(9):1167-1181 (2012)), and according to Tables 2A and 2B, a radiation dose deposit of at least 10% is obtained following nanoparticle and/or nanoparticle aggregate delineation of the tumor bed and the subsequent irradiation of said nanoparticles and/or nanoparticle aggregates, when using a biocompatible gel according to the invention, i.e., a biocompatible gel comprising nanoparticles and/or nanoparticle aggregates, wherein: i) the density of each nanoparticle and nanoparticle aggregate is of at least 7 g/cm.sup.3, the nanoparticle or nanoparticle aggregate comprising an inorganic material comprising at least one metal element having an atomic number Z of at least 25, preferably of at least 40, each of said nanoparticle and of said nanoparticles aggregate being covered with a biocompatible coating; ii) the nanoparticles' and/or nanoparticle aggregates' concentration is of at least about 1% (w/w); and iii) the apparent viscosity at 2 s.sup.1 of the gel comprising nanoparticles and/or nanoparticle aggregates is between about 0.1 Pa.Math.s and about 1000 Pa.Math.s when measured between 20 C. and 37 C.

TABLE-US-00002 TABLE 2A Concentration of nanoparticles in the rim assuming an initial nanoparticle concentration within the gel of 10 g/L. Tumor diameter and margin (i.e., tumor excision including typically between 0.5 Tumor Tumor Nanoparticle Nanoparticles Delineation of nanoparticles following deposition and 2 cm of bed bed concentration quantity on the tumor bed: Calculation of the volume of the macroscopic radius volume within gel within tumor rim (m.sup.3) margin) (m) (m) (m.sup.3) (g/m.sup.3) bed (g) Rim = 0.1 mm Rim = 0.5 mm Rim = 1 mm Rim = 2 mm 0.010 0.005 5.24E07 10,000 0.0052 3.08E08 1.42E07 2.56E07 4.11E07 0.020 0.010 4.19E06 10,000 0.0419 1.24E07 5.98E07 1.14E06 2.04E06 0.030 0.015 1.41E05 10,000 0.1414 2.81E07 1.37E06 2.64E06 4.94E06 0.040 0.020 3.35E05 10,000 0.3351 5.00E07 2.45E06 4.78E06 9.08E06 0.050 0.025 6.55E05 10,000 0.6546 7.82E07 3.85E06 7.54E06 1.45E05 0.060 0.030 1.13E04 10,000 1.1311 1.13E06 5.56E06 1.09E05 2.11E05 0.070 0.035 1.80E04 10,000 1.7962 1.54E06 7.59E06 1.50E05 2.91E05 0.080 0.040 2.68E04 10,000 2.6812 2.01E06 9.93E06 1.96E05 3.82E05 0.090 0.045 3.82E04 10,000 3.8175 2.54E06 1.26E05 2.49E05 4.87E05 Concentration of Nanoparticles in the Rim (g/l) Rim = 0.1 mm Rim = 0.5 mm Rim = 1 mm Rim = 2 mm 170 37 20 13 337 70 37 20 503 103 53 29 670 137 70 37 837 170 87 45 1003 203 103 53 1170 237 120 62 1337 270 137 70 1503 303 153 78

TABLE-US-00003 TABLE 2B Concentration of nanoparticles in the rim assuming an initial nanoparticle concentration within the gel of 35 g/L. Tumor diameter and margin (i.e., tumor excision including typically between Tumor Tumor Nanoparticle Nanoparticle Delineation of nanoparticles following deposition on 0.5 and 2 cm of bed bed concentration quantity the tumor bed: Calculation of the volume of the rim macroscopic radius volume within gel within tumor (m.sup.3) margin) (m) (m) (m.sup.3) (g/m.sup.3) bed (g) Rim = 0.1 mm Rim = 0.5 mm Rim = 1 mm Rim = 2 mm 0.01 0.005 5.24E07 35,000 0.0183 3.08E08 1.42E07 2.56E07 4.11E07 0.02 0.010 4.19E06 35,000 0.1466 1.24E07 5.98E07 1.14E06 2.04E06 0.03 0.015 1.41E05 35,000 0.4949 2.81E07 1.37E06 2.64E06 4.94E06 0.04 0.020 3.35E05 35,000 1.1730 5.00E07 2.45E06 4.78E06 9.08E06 0.05 0.025 6.55E05 35,000 2.2910 7.82E07 3.85E06 7.54E06 1.45E05 0.06 0.030 1.13E04 35,000 3.9589 1.13E06 5.56E06 1.09E05 2.11E05 0.07 0.035 1.80E04 35,000 6.2866 1.54E06 7.59E06 1.50E05 2.91E05 0.08 0.040 2.68E04 35,000 9.3841 2.01E06 9.93E06 1.96E05 3.82E05 0.09 0.045 3.82E04 35,000 13.3614 2.54E06 1.26E05 2.49E05 4.87E05 Concentration of Nanoparticles in the Rim (g/l) Rim = 0.1 mm Rim = 0.5 mm Rim = 1 mm Rim = 2 mm 595 129 72 45 1178 245 129 72 1762 362 187 100 2345 479 245 129 2928 595 304 158 3512 712 362 187 4095 828 420 216 4678 945 479 245 5262 1062 537 275

Example 8: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (5% w/w) within a Hyaluronic Acid Gel (3% w/w)

[0147] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1 is added to a volume of gel, typically with a polymer (hyaluronic acid) concentration lying between 2.5% w/w and 4% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel is adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 5% (w/w). The preparation thus obtained is typically mixed with a magnetic stirrer or a spatula.

Example 9: Viscosity Measurement of a Gel Composed of Hyaluronic Acid (3% w/w) and a Gel from Example 8 Composed of Hyaluronic Acid (3% w/w) Comprising Nanoparticles and/or Nanoparticle Aggregates (5% w/w) Consisting of Hafnium Oxide

[0148] Viscosity measurement is typically performed, at 20 C. and 37 C., using a Couette rheometer and following the standard DIN ISO 3219 recommendations (Model RM200, Lamy Rheology), on a given range of shear rates, lying between 0.1 s.sup.1 and 20 s.sup.1. The apparent viscosity is reported at 2 s.sup.1. The absence of strong interaction between the particles and the polymer which forms the biocompatible gel can typically be verified by measuring the viscosity of the gel comprising the nanoparticles and/or nanoparticle aggregates at 20 C. and 37 C., as described above, and by comparing the obtained viscosity curve with that of a gel comprising neither nanoparticles nor nanoparticle aggregates. The apparent viscosity at 2 s.sup.1 for both gels is higher than 150 Pa.Math.s at 20 C. and higher than 100 Pa.Math.s at 37 C. The similar viscosity curves observed (i.e., values differing one from each other by no more than 20%, typically by no more than 15%) confirm the absence of strong interaction between nanoparticles and/or nanoparticle aggregates and gel (see FIGS. 5A and 5B).

Example 10: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (0.26% w/w) within the Gel of Hyaluronic Acid (0.1% w/w)

[0149] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1 is added to a volume of gel typically with a polymer (hyaluronic acid) concentration lying between 0.05% w/w and 0.25% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel is adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 0.26% (w/w). The preparation thus obtained is typically mixed with a magnetic stirrer or a spatula.

Example 11: FTIR (Fourier Transform Infrared Spectroscopy) Spectra of the Gel of Example 10 and Comparison with a Gel Composed of Hyaluronic Acid and Also with Nanoparticles and/or Nanoparticle Aggregates

[0150] The bands observed in the gel embedding biocompatible hafnium oxide nanoparticles and/or nanoparticle aggregates correspond to the bands characteristic of the gel composed of hyaluronic acid and to the bands of nanoparticles and/or nanoparticle aggregates consisting of hafnium oxide. No characteristic bands of one or the other of the components are missing and no new bands appear. FTIR spectra show no signature revealing an interaction between nanoparticles and/or nanoparticle aggregates and gel (see FIG. 6 and Tables 3 and 4 below).

TABLE-US-00004 TABLE 3 FTIR bands assignment for hyaluronic acid (from Pasqui, D. et al., Polysaccharide-based hydrogels: the key role of water in affecting mechanical properties, Polymers, Vol. 4, p. 1517-1534, 2012). hyaluronic acid wavenumber (cm.sup.1) assignment 3310 water moleculesOH 2930 CCCH stretching 2875 CCCH stretching 1640 amide CO stretching 1610 carboxylate asymm. stretching 1560 amide NH bending 1410 carboxylate asymm. stretching 1375 CCH and OCH stretching 1281 CO stretching 1146 CC CO stretching 1046 COC bending

TABLE-US-00005 TABLE 4 FTIR bands assignment for hafnium oxide (from Ramadoss, A. et al., Synthesis and characterization of HfO.sub.2 nanoparticles by sonochemical approach, Journal of Alloys and Compounds, Vol. 544, p. 115-119, 2012). HfO.sub.2 wavenumber (cm.sup.1) assignment 3417 stretching OH 1628 bending HOH 1011 coating 755 m-HfO.sub.2 675 m-HfO.sub.2 523 m-HfO.sub.2 419 m-HfO.sub.2

Example 12: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (5% w/w) within the Gel (Hyaluronic Acid 3.8% w/w) Prior to Gel Deposition on the Tumor Bed

[0151] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1 is added to a volume of gel, typically with a polymer (hyaluronic acid) concentration lying between 3.3% w/w and 4.3% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel is adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 5% (w/w).

Example 13: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (5% w/w) within the Gel (Hyaluronic Acid 2.5% w/w) Prior to Gel Deposition on the Tumor Bed

[0152] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1 is added to a volume of gel, typically with a polymer (hyaluronic acid) concentration lying between 2% w/w and 3% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel is adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 5% (w/w).

Example 14: Biocompatible Hafnium Oxide Nanoparticles' and/or Nanoparticle Aggregates' Incorporation (5% w/w) within the Gel (Auto-Cross-Linked Hyaluronic Acid 3% w/w) Prior to Gel Deposition on the Tumor Bed

[0153] A volume of aqueous suspension of biocompatible HfO.sub.2 nanoparticles from example 1 is added to a volume of gel, typically with a polymer (auto-cross-linked hyaluronic acid) concentration lying between 2.5% w/w and 3.5% w/w. The volume ratio between the suspension of HfO.sub.2 nanoparticles and the gel is adjusted to reach a final HfO.sub.2 nanoparticle concentration within the gel of 5% (w/w).

Example 15: Assessment by Computed Tomography (CT) of the Quality of Tumor Bed Delineation Obtained when Using Nanoparticles Respectively Embedded in Hydrogels from Examples 12, 13 and 14

[0154] The objective of this experiment was to assess, by CT (Computed Tomography), the quality of tumor bed delineation by nanoparticles (NPs). The test gels from example 12 (FIG. 7, top panel), example 13 (FIG. 7, middle panel) and example 14 (FIG. 7, bottom panel) were implanted (deposited) into the cavities left by the resection of EMT-6 orthotopic grafted tumors (murine breast carcinoma cancer cells) in BALB/cJRj mice. The CT analysis was performed 30 minutes, 1 day, 2 days, 8 days and 22 days following gel implantation into the cavity left by the resection of the tumor in order to evaluate the volume occupied by the nanoparticles and/or nanoparticle aggregates in the tumor bed over time. For this, a manual segmentation (region of interest (ROI)) was performed around the surgical cavity. Then a thresholding above 120 HU was performed inside the surgical cavity in order to evaluate the presence of nanoparticles or nanoparticle aggregates and to assess both the location and volume occupied by those nanoparticles or nanoparticle aggregates for all mice. FIG. 7 presents the CT images showing more than about 80% of cavity delineation as soon as 3 days following surgery and gel implantation.

[0155] Following their release from gels, the deposition of nanoparticles and/or nanoparticle aggregates on the tumor bed typically occurs within 3 days (see FIG. 7).

REFERENCES

[0156] Customized Computed Tomography-Based Boost Volumes in Breast-Conserving Therapy: Use of Three-Dimensional Histologic Information for Clinical Target Volume Margins. IJROB 75(3) 757-763 (2009). [0157] Target volume definition for external beam partial breast radiotherapy: clinical, pathological and technical studies informing current approaches. Radiotherapy and Oncology 94 255-263 (2010). [0158] Excised and Irradiated Volumes in Relation to the Tumor size in Breast-Conserving Therapy. Breast Cancer Res. Treat. 129:857-865 (2011). [0159] Guidelines for target volume definition in post-operative radiotherapy for prostate cancer, on behalf of the EORTC Radiation Oncology Group. Radiotherapy & Oncology 84 121-127 (2007). [0160] Improving the definition of the tumor bed boost with the use of surgical clips and image registration in breast cancer patients. Int. J. Radiation Oncology Biol. Phys. Vol 78(5):1352-1355 (2010). [0161] The dynamic tumor bed: volumetric changes in the lumpectomy cavity during breast conserving therapy. Int. J. Radiation Oncology Biol. Phys. 74(3):695-701 (2009). [0162] Nanoscale Radiotherapy with Hafnium Oxide Nanoparticles. Future Oncology 8(9):1167-1181 (2012). [0163] Polysaccharide-based hydrogels: the key role of water in affecting mechanical properties. Polymers 4: 1517-1534, 2(2012). [0164] Ramadoss A. et al. Synthesis and characterization of HfO.sub.2 nanoparticles by sonochemical approach. Journal of Alloys and Compounds 544:115-119 (2012).