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Title: A theoretical and experimental investigation of polarised X-rays for the in-vivo measurements of heavy metals
Author: Kilic, A.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1995
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A Monte Carlo has been developed, using the EGS4 code, to aid the design and optimisation of a polarised source for in vivo X-ray fluorescence (XRF) analysis of platinum (Pt). The modelled code is based on a 300 kV clinical X-ray therapy unit at Singleton Hospital. The code handles five individual components (X-ray tube, filter, polariser, sample and detector) which the user assembles as needed, thus allowing the facility for simulation of a wide variety of XRF systems. For each component, all the physical dimensions and materials involved are set by the user. The model includes polarised photon transport modification, K-edge fluorescent photon transport modification and K-edge sampling method for mixtures (a facility previously available for simple compounds). It incorporates a variance reduction technique (forcing photon interaction) and uses random number generator called RANMAR. Also EGS4PICT (The EGS4 Shower Display System for PC) is built in to display a shower picture at every stage of simulation. The clinical motivation for the measurement of Pt is the need to investigate the kinetics of Pt-based chemotherapy drugs used for the treatment of head and neck tumours in cancer patients. Accurate measurement of tumour Pt concentration can provide important information in establishing dose-response relationships and therefore optimising treatment to obtain maximum therapeutic effect. Several computer experiments are employed to find optimum geometrical configuration and maximise sensitivity for the polarised XRF system. The selected polariser materials tested are C, Al, Fe, Cu, Sn and Pb. The material shape and thickness is investigated. The secondary beam collimator diameter, length and material is also studied. Results are compared with analytical models and experiment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available