Laue lens for radiotherapy applications through a focused hard x-ray beam: a feasibility study on requirements and tolerances

Abstract

Focusing a hard x-ray beam would represent an innovative technique for tumour treatment, since such a beam may deliver a dose to a tumour located at a given depth under the skin, sparing the surrounding healthy cells. A detailed study of a focusing system for hard x-ray aimed at radiotherapy is presented here. Such a focusing system, named Laue lens, exploits x-ray diffraction and consists of a series of crystals disposed as concentric rings capable of concentrating a flux of x-rays towards a focusing point. A feasibility study regarding the positioning tolerances of the crystalline optical elements has been carried out. It is shown that a Laue lens can effectively be used in the context of radiotherapy for tumour treatments provided that the mounting errors are below certain values, which are reachable in the modern micromechanics. An extended survey based on an analytical approach and on simulations is presented for precisely estimating all the contributions of each mounting error, analysing their effect on the focal spot of the Laue lens. Finally, a simulation for evaluating the released dose in a water phantom is shown.

Design and modeling of a Laue lens for radiation therapy with hard x-ray photons

“…The dose rate we obtain here is ∼50 lower than in the study of a Laue lens for radiation therapy published by Paternò et al (2016). This study is complemented by the paper from Camattari (2017), which gives details on the treatment of diffraction in crystals that is used to produce this estimated dose rate. The fact that their study is based on a somewhat different Laue lens can not explain the dose rate difference.…”

Feasibility Study of Multi Laue Lens Based SPECT with a Dedicated 3D Reconstruction Algorithm: A First Monte Carlo Study

“…A tracking Monte Carlo genetic algorithm in Mathematica 31 was developed and used to model and optimize the Laue lens design, which we propose to couple to the SPECT system. The optimization criteria are based on attaining the highest photon diffraction sensitivity, defined as the number of diffracted photons divided by the number of photons emitted by an isotropic source and the smallest focal length necessary to obtain a compact design.…”

Comment on ‘Design and modeling of a Laue lens for radiation therapy with hard x-ray photons’

“…The technical details of this code, which was developed in Mathematica, were not discussed in the paper, nor was the absolute dose rate value delivered to a target of finite size evaluated. Since the error committed in the paper of Paternò and colleagues has no relation with the formulas that can be found in the paper of Camattari (2017), the citation of Camattari's paper in the one of Girou and colleagues seems to be not pertinent.…”

“…The paper of Camattari (2017) is cited in the last paragraph of section 4.3 of the paper of Girou and colleagues. The formulas reported in Camattari's paper aimed at providing an estimation of the crystal misalignments and mispositioning effects on the diffraction spot.…”