Iodine-substituted hydroxyapatite nanoparticles and activation of derived ceramics for range verification in proton therapy.

Osteosarcoma is a radioresistant cancer, and proton therapy is a promising radiation alternative for treating cancer with the advantage of a high dose concentration in the tumor area. In this work, we propose the use of iodine-substituted hydroxyapatite (IHAP) nanomaterials to use iodine (I) as a proton radiation tracer, providing access to range verification studies in mineralized tissues. For this purpose, the nanomaterials were synthesized at four iodine concentrations hydrothermal synthesis.

In vivo production of fluorine-18 in a chicken egg tumor model of breast cancer for proton therapy range verification.

Range verification of clinical protontherapy systems via positron-emission tomography (PET) is not a mature technology, suffering from two major issues: insufficient signal from low-energy protons in the Bragg peak area and biological washout of PET emitters. The use of contrast agents including O, Zn or Cu, isotopes with a high cross section for low-energy protons in nuclear reactions producing PET emitters, has been proposed to enhance the PET signal in the last millimeters of the proton path. However, it remains a challenge to achieve sufficient concentrations of these isotopes in the target volume.

Dictionary-based software for proton dose reconstruction and submilimetric range verification.

This paper presents a new method for fast reconstruction (compatible with in-beam use) of deposited dose during proton therapy using data acquired from a PET scanner. The most innovative feature of this novel method is the production of noiseless reconstructed dose distributions from which proton range can be derived with high precision.A new MLEM & simulated annealing (MSA) algorithm, developed especially in this work, reconstructs the deposited dose distribution from a realistic pre-calculated activity-dose dictionary.