Optimization of low-dose, low cost mobile 3D X-ray Imaging

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Digital Tomosynthesis (DT) is a 3D mode of X-ray imaging. This imaging mode extracts both the typical2D information you would expect from an x-ray image, as well as depth information on the body beingimaged. This is conventionally achieved by altering the angle of an x-ray tube over a set angular range,where the image created at each unique angle corresponds to a certain layer of depth of the imaged body[1]. These images can be reconstructed using reconstruction algorithms [2] to create a singular imagewith enhanced contrast between the object of interest and background than is seen in 2D x-ray images.However, conventional DT imaging machines for medical purposes require high power to be operated, andare too large to be portable and hence have no application in bedside imaging.A portable DT system created by Adaptix Ltd [3] has changed this. This system has been designed andconstructed which uses cold-cathode, flat panel x-ray source (FPS) arrays. These arrays are constructed of25 individual emitters that emit sequentially, creating the multiple projections conventionally created bythe rotation of the x-ray tube [4]. This device has been successful for small animal and human orthopaedicimaging. Hence, proof-of-concept for the scaling up of this for chest imaging purposes has been shown [5]and active research is now underway for the development of this potential low-cost and portable methodof chest DT imaging. This technology sees additional application in non-destructive material evaluation(NDE) and dentistry contexts.This PhD project aims to utilise Geant4 [6], a Monte-Carlo simulation software, to address the engineeringand science questions that arise within the further development of these devices. Initial work has beencompleted to investigate the effect of different x-ray target constructions on the x-ray spectra producedand hence the dosage to the patient and the quality of the image outputted. Ongoing work endeavours todevelop this simulation framework further by implementing a realistic detector to allow closer comparisonof the images created from this work to those outputted from the physical device itself. This shouldadditionally inform a discussion on the optimal detector construction for this DT approach and identifyhow best to parameterise detector quality in this context. Future work is planned to follow on fromthis by applying this benchmarked simulation environment to look at modern x-ray approaches, suchas dual-energy imaging, to identify how best to adapt the device for these novel capabilities. This willcreate simulation data that can then be experimentally verified with the device itself. Hence, the projectnarrative will reflect the development of an accurate simulation environment within the Geant4 softwarewhich can be used to address practical questions raised when constructing this technology in a morecost- and labour-efficient method than can be achieved experimentally. Comparison with existing datawill ensure accurate benchmarking to prove the reliability of the simulation and hence allow it to informfuture developments in combination with experimental work.References[1] Shinn Huey Chou, Greg A. Kicska, Sudhakar N. Pipavath, and Gautham P. Reddy. Digital tomosynthesisof the chest: Current and emerging applications. Radiographics, 34:359-372, 3 2014.[2] Vadim Y Soloviev, Kate L Renforth, Conrad J Dirckx, and Stephen G Wells. Physics in medicinebiology physics in medicine biology meshless reconstruction technique for digital tomosynthesis. Phys.Med. Biol, 65:85010, 2020.[3] Adaptix Ltd, https://adaptix.com/.[4] Thomas Primidis. Design and optimisation of ultra-compact, high-resolution 3d x-ray imaging systems.2022.1[5] Thomas G Primidis, Stephen G Wells, Vadim Y Soloviev, and Carsten P Welsch. 3d chest tomosynthesisusing a stationary flatpanel source array and a stationary detector: a monte carlo proof ofconcept. 2021