Method of producing a radiometric physical phantom of a biological organism and physical phantom produced by this method

A radiometric physical phantom of a biological organism for experimental determination, under predetermined irradiating conditions, of the volume distribution of radiation doses received by the phantom representing the dose distribution which would be received by the biological organism placed under the same irradiating conditions, the biological organism having at least two volumes of biological tissues having distinctly differing chemical compositions and densities, characterized in that the physical phantom comprises:

• at least two chambers, held in position within a supporting frame, delimited by respective walls formed of solid 3D printing ink transparent to radiation, and each filled with a different dosimetric gel;
• the at least two chambers having different, separate radiological volumes, each radiological volume being identical to, or close to via smoothing of contours, the sum of the volumes of a complete group of grouped biological tissues of the biological organism that is radiologically imitated, said grouped tissues being adjacent and having close chemical compositions and densities;
• and
• the dosimetric gels filling said chambers each having physical characteristics close to the chemical compositions and densities of the grouped adjacent biological tissues, the sum of the volumes thereof being identical to, or close to via smoothing, the radiological volume of the chamber that is filled with the gel.

A system to produce a radiometric physical phantom simulating the radiation absorption and diffusion properties of a biological organism, the biological organism having at least two volumes of biological tissues with distinctly differing chemical compositions and densities, the system comprising:

• means to provide one or more three-dimensional anatomical images of the tissues in terms of chemical composition and density;
• an electronic computer configured:
• from one or more three-dimensional anatomical images of the tissues in terms of chemical composition and density, to determine a three-dimensional radiological model representing radiation absorption and diffusion inside the biological organism, by grouping together in radiological organs those tissues that are adjacent and have close chemical compositions and densities;
• each radiological organ geometrically occupying in space a radiological volume equal to, or close to via smoothing of its enveloping contours, the sum of the volumes of all the tissues grouped together within the same radiological organ, and being characterized by a radiological class identifying the range of close chemical compositions and densities of the tissues grouped together in the same radiological organ;
• and
• from the three-dimensional radiological model, to determine the plans of a material frame of the phantom as being a set of chambers, ducts for filling the chambers with gel and supporting elements to hold the chambers in position together, then to translate the plans of the material frame into a 3D print control programme to be executed by a predetermined 3D printer,
• the predetermined 3D printer being configured to produce the material frame of the phantom non-filled with dosimetric gels, using 3D printing inks transparent to radiation;
• at least two different dosimetric gels each intended to fill a different radiological chamber associated with a different radiological organ in terms of class of chemical composition and density;
• and
• means to fill the empty phantom with the at least two dosimetric gels.