Analysis of a novel X-ray lens for converging beam radiotherapy

Dirk A Bartkoski,Asaf Zuck,Shirly Borukhin,Aharon Bar-David,Zeev Burshtein,Ramesh Tailor,Jamshid Moradi-Kurdestany,Michael Kleckner,Mohammad Salehpour,Dragan Mirkovic,Ze’Ev Harel

doi:10.1038/s41598-021-98888-8

Abstract

We describe the development and analysis of a new teletherapy modality that, through a novel approach to targeted radiation delivery, has the potential to provide greater conformality than conventional photon-based treatments. The proposed system uses an X-ray lens to reflect photons from a conventional X-ray tube toward a focal spot. The resulting dose distributions have a highly localized peak dose, with lower doses in the converging radiation cone. Physical principles governing the design of this system are presented, along with a series of measurements analyzing various characteristics of the converging beam. The beam was designed to be nearly monoenergetic (~ 59 keV), with an energy bandwidth of approximately 10 keV allowing for treatment energies lower than conventional therapies. The focal spot was measured to be approximately 2.5 cm long and 4 mm wide. Mounting the proposed X-ray delivery system on a robotic arm would allow sub-millimeter accuracy in focal spot positioning, resulting in highly conformal dose distribution via the optimal placement of individual focal spots within the target volume. Aspects of this novel radiation beam are discussed considering their possible clinical application as a treatment approach that takes maximum advantage of the unique properties afforded by converging X-ray beam therapy.

Highlights

We describe the development and analysis of a new teletherapy modality that, through a novel approach to targeted radiation delivery, has the potential to provide greater conformality than conventional photon-based treatments
This report describes the fundamental principles of converging beams and a novel treatment device developed by Convergent Radiotherapy and RadioSurgery (CRnR; Tirat Carmel, Israel) that incorporates a Bragg-reflecting X-ray lens[1]
The novelty of the converging radiotherapy beam approach required a wide range of measurements to quantify and analyze the beam characteristics to facilitate implementing this approach into clinical environments

Summary

Introduction

We describe the development and analysis of a new teletherapy modality that, through a novel approach to targeted radiation delivery, has the potential to provide greater conformality than conventional photon-based treatments. Mounting the proposed X-ray delivery system on a robotic arm would allow sub-millimeter accuracy in focal spot positioning, resulting in highly conformal dose distribution via the optimal placement of individual focal spots within the target volume. Aspects of this novel radiation beam are discussed considering their possible clinical application as a treatment approach that takes maximum advantage of the unique properties afforded by converging X-ray beam therapy. Most conventional radiotherapy systems include radiation sources that produce diverging radiation beams that must be collimated to achieve the correct target distribution This divergence introduces a dose gradient that decreases with distance from the source. The relative dose distributions of a conventional diverging beam from a linear accelerator with a 60-keV orthovoltage beam, along with a converging quasi-monoenergetic 60-keV beam as produced by the CRnR

Methods

Results

Discussion

Conclusion