A Unique Prototypic Device for Radiation Therapy: The p53-Independent Antiproliferative Effect of Neutron Radiation.

Radiation therapy with heavy particles including neutrons, an otherwise therapeutically perspective because of its high tissue penetration and efficient tumor damage, is currently limited by the lack of adequate equipment. An NG-24 generator (140 kg, 42 × 110 cm, ~1011 particles/s, > 14 MeV) has been designed and engineered to replace the huge and environmentally harmful neutron reactors, cyclotrons, and accelerators with a compact, portable, safe, and potent source of high-energy neutrons. We demonstrate that the neutron beam produced by NG-24 causes a significant antiproliferative effect on human tumor cell lines regardless of the status of the anti-apoptotic p53 protein. Phosphorylation of histone 2A and increased amounts of p21, cyclin D, and phospho-p53 were detectable in HCT116 colon carcinoma cells (wild-type p53) irradiated with 4 Gy several days post-treatment, accompanied by G2/M phase arrest. These treatments dramatically reduced the ability of single cells to form colonies. In the HCT116p53KO subline (p53 -/-), the G2/M arrest was independent of the aforementioned mechanisms. Hence, the NG-24 generator is a source of a powerful, therapeutically relevant neutron flux that triggers a p53-independent antiproliferative response in tumor cells.

Characteristics of miniature pulsed penning ion source: Experiment and PIC simulation.

In the present work, the results of the experimental and particle in cell (PIC) simulation studies of the discharge combustion modes in a miniature Penning ion source (PIS) under the pulse-periodic power supply conditions are presented. Dynamics of discharge ignition and discharge operation mode at a pulsed anode voltage supply are investigated for different values of anode voltage and gas pressure in various magnetic field configurations. Typical examples of current pulse waveforms are shown. Also, numerical simulations of the PIS were performed using 3D PIC combined with Monte Carlo collisions in the code VSim. Temporal dependencies of electron, ion, and potential distributions in the Penning cell are simulated. Differences between the numerical and experimental results are discussed.