Application of polarised X-ray for the in vivo measurements of platinum in the head and neck and the kidney of cancer patients treated with platinum-based chemotherapy drugs

• Main Author: Kadhim, R. A. G.
• Published: Swansea University 2003
• Subjects: 615.84
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637746

A non-invasive <i>in vivo</i> method of measuring platinum concentration in the kidneys of patients receiving chemotherapy has been developed and optimized. The method is based on polarising the x-ray beam from an orthovoltage radiotherapy treatment unit, the Pantak DXT-300, and using the polarised beam to simulate emission of the characteristic platinum x-rays from the kidney. The platinum is contained in platinum-based chemotherapy drugs, such as cisplatin and its analogues (carboplatin and iproplatin), used to treat cancer patients. The clinical motivation for measuring platinum concentration in both the kidneys and the tumour is to optimize the treatment by establishing relationships between the accumulations of the drug at those sites. Such clinical information could be of use in maximising the therapeutic ratio towards the tumour tissue and limiting the hazards towards the kidney. A Semi-Automatic Techniques (SAT) model for data handling, displaying and analysis of an x-ray fluorescent spectrum from Ge semiconductor detectors has been developed for a personal computer under MS-DOS version ³ 5. The model employed linear and non-linear least squares fitting for analysing the data. A Monte Carlo model has been developed; using the MCNP-4B code to estimate the optimum thickness of the tin filter. Clinical measurements were carried out on the tumour and kidney of seven head and neck cancer patients undergoing treatment with different platinum-based chemotherapy drugs. A measurable platinum concentration is observed in the tumour and the kidney of some patients, using the existing head and neck and new developed kidney polarised x-ray fluorescence systems. The preliminarily results shows that some patients respond well to the drugs, the platinum concentration in the kidney is higher with cisplatin than with carboplatin, and the cytotoxicity of cisplatin is higher than that of carboplatin.