Early effects comparison of X rays delivered at high-dose-rate pulses by a plasma focus device and at low dose rate on human tumour cells

Abstract

A comparative study has been performed on the effects of high-dose-rate (DR) X-ray beams produced by a plasma focus device (PFMA-3), to exploit its potential medical applications (e.g. radiotherapy), and low-DR X-ray beams produced by a conventional source (XRT). Experiments have been performed at 0.5 and 2 Gy doses on a human glioblastoma cell line (T98G). Cell proliferation rate and potassium outward currents (IK) have been investigated by time lapse imaging and patch clamp recordings. The results showed that PFMA-3 irradiation has a greater capability to reduce the proliferation rate activity with respect to XRT, while it does not affect IK of T98G cells at any of the dose levels tested. XRT irradiation significantly reduces the mean IK amplitude of T98G cells only at 0.5 Gy. This work confirms that the DR, and therefore the source of radiation, is crucial for the planning and optimisation of radiotherapy applications.

Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device

“…Moreover, PFMA-3 manufacturing, utilization and radiation protection arrangements require quite low costs in contrast to the high application flexibility ( Table 2 ). Preliminary data about antitumor efficacy of PFMA-3 have been obtained in glioblastoma (T98G cell line) [ 12 ] and breast cancer preclinical models (MCF-7 cell line) [ 13 ]. Although the effects of an important DR variation after low-LET radiation has been reported for several years [ 55 ], up to now limited recent biological data have been published on very high DR effect in tumor.…”

“…One, biologic, is related to radiosensitization of tumor cells (without sensitizing normal tissue cells), mostly through targeted and immune therapies [ 6 – 11 ]. The other one, technologic, is more focused on improvement of accuracy in delivering ionizing radiation (IR) and on generation of greater radiation beams, for example with a higher dose rate (DR), to counteract radioresistance [ 3 , 12 – 18 ]. DR, the quantity of radiation absorbed per unit time, is one of the principal factors determining the biological consequences of a given absorbed dose.…”

“…DR, the quantity of radiation absorbed per unit time, is one of the principal factors determining the biological consequences of a given absorbed dose. As the DR is increased and the exposure time reduced, the biological effects are generally more significant [ 12 , 19 , 20 ]. A number of in vitro studies have been conducted and a wide range of DRs has been used, between the seventies and the nineties, to assess the low-Linear Energy Transfer (LET) dose-rate effect.…”

Analysis and characterization of the X‐ray beam produced by a PF device for radiotherapy applications

“…The purpose of the irradiation tests is to assess the radiobiological effectiveness (RBE) of the high dose rate X‐rays produced by the PFMA‐3, in comparison with conventional X‐ray devices (XRT), to confirm the encouraging results already obtained in past experimental campaigns . Two samples of the cell culture MCF‐7 were treated with PFMA‐3, whereas two comparison samples, kept in the same conditions, were irradiated with a conventional X‐ray tube.…”

“…[17,18] Two samples of the cell culture MCF-7 were treated with PFMA-3, whereas two comparison samples, kept in the same conditions, were irradiated with a conventional X-ray tube. The same radiobiological analyses have then been conducted on the samples to make a comparison of RBE between the two methods.…”