Laue lens to focus an X-ray beam for radiation therapy

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• 作者：Gianfranco Paternò ; Michele Marziani ; Riccardo Camattari ; Valerio Bellucci ; Andrea Mazzolari ; Mauro Gambaccini and Vincenzo Guidi
• 关键词：Laue lenses ; radiation therapy ; X-ray beams ; dose delivery
• 刊名：Journal of Applied Crystallography
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：49
• 期：2
• 页码：468-478
• 全文大小：1728K
• ISSN：1600-5767

文摘

A Laue lens is an optical component composed of a set of crystals that produce a convergent beam exploiting X-ray diffraction in transmission geometry. Employment of a system formed by a properly designed Laue lens coupled with an X-ray unit to selectively irradiate tumours is proposed. A convergent beam leads to a depth dose profile with a pronounced peak at the focal depth, which may result in a high precision of the dose delivery. Using a custom-made Monte Carlo code and the GAMOS code, we carried out a design study to determine the geometry and the optimal features of the crystals composing the lens. As an application, a Laue lens capable of focusing a 80 keV beam 50 cm downstream of the lens has been designed. The lens is composed of an ensemble of Si crystals with curved diffracting planes. The lens produces a focal spot of 2 mm enclosing 7.64 × 10⁶ photons for an electron charge of 1 mC impinging on the surface of the X-ray tube anode. The combination of these important figures of merit makes the proposed system suitable for irradiating both sub-cm and larger tumour masses efficiently. A dose of 2 Gy can be delivered to a small tumour in a few seconds, sparing at the same time the surrounding tissues.