Accurate verification of dose delivery in stereotactic radiotherapy is a core responsibility of medical physicists, particularly for systems such as Gamma Knife (GK) radiosurgery, where nearly 200 converging beams produce highly localised dose distributions with sub-millimetre precision. Despite substantial advances in planning and delivery systems, quality assurance (QA) for GK continues to rely on radiochromic film. This analogue workflow is inherently labour-intensive, vulnerable to handling and scanning artefacts, and restricts how frequently centres can perform plan-specific QA. 

To address these limitations, we are developing a digital alternative to X-ray film for small-field dosimetry: a thin, flexible digital X-ray film (DXF) based on Silveray’s nanocomposite semiconductor material (NPX). The NPX layer combines bismuth oxide nanoparticles with an organic semiconductor matrix to achieve high sensitivity and spatial resolution, deposited on a pixelated flexible thin-film transistor backplane. The complete detector can be embedded directly into existing GK phantoms with negligible beam perturbation, providing real-time, high-resolution 2D and 3D dose maps without the need for film processing or scanning.

Although initially targeted at GK, the detector architecture is adaptable to linac-based stereotactic radiotherapy, brachytherapy, and routine high-resolution QA tasks. By digitising QA workflows, this technology aims to increase QA frequency, reduce operational burden for physics teams, and enhance confidence in dose delivery.