X-ray resonance therapy with parametric X-ray radiation (PXR) for sulfur-containing tumor tissues

TL;DR

The paper investigates selective therapy for sulfur-rich tumor tissues using parametric X-ray radiation (PXR) to exploit resonant sulfur absorption near the K-edge at $E_K \approx 2.4\ \mathrm{keV}$. By modeling sulfur photoionization and deriving the dose–response with a compact, tunable PXR source, it shows that a beam with narrow spectral-angular distribution can achieve effective sulfur ionization while potentially reducing healthy-tissue dose. The analysis predicts feasible PXR parameters (e.g., $N_{ph} \approx 3×10^{11}$ ph/s and $\Delta\omega/\omega_B \approx 10^{-2}$) using a 25 MeV beam on a Si(111) crystal, delivering about $1.3$ Gy in a representative session and outperforming conventional X-ray approaches in select contexts. The work argues for the potential of hospital-based, sulfur-targeted radiotherapy, pending experimental validation and optimization of source design.

Abstract

We investigate the possibility of usage of the parametric X-ray radiation (PXR) for the selective therapy of superficial sulfur-containing tumor tissues. In these tissues, the concentration of sulfur atoms is significantly higher than in healthy ones. Accordingly, the destruction of cancer cells is caused by the ionization of sulfur atoms. The selective nature of the therapy is determined by the narrow spectral-angular distribution of the PXR photon beam and the resonant absorption of radiation by sulfur atoms. This leads to a significant decrease in the total dose required to achieve the desired effects compared to irradiation with conventional X-ray tubes or electron accelerators.

Figures (2)

• Figure 1: Scheme of the PXR generation
• Figure 2: Spectra photo-ionisation of S (solid line) and PXR (dash line)