GeB flat fibre TL dosimeters for in-vivo measurements in radiosurgery

Noting an increase in demand for procedures involving clinical radiosurgery we seek to develop a high spatial resolution thermoluminescence dosimeter (TLD) allow conduct of vivo dose verification measurements. An associated need is dynamic range exceeding that the well-established LiF (Mg,Ti) phosphor TLD-100, with particular latter being limited performance at elevated doses seen radiotherapy. The work investigates novel GeB co-doped Flat Fibre (GeB-FF) fabricated using modified chemical vapour deposition (MCVD) process, hollow capillary optical fibres (COF) produced from this collapsed down into flat (FF) create strain-related defects. This process has already been demonstrated low sensitivity fibres, notably diagnostic x-ray potentials, Minimum Detectable Dose (MDD) values 0.1 μGy. intent present work, conducted as component safety audit, part hospital periodic radiation protection quality assurance program, examine and compare two forms TL dosimeter, GeB-FF measuring scattered resulting cranial cavity procedures. dosimeters were placed on neck, chest pelvis 20 patients. Using both types raw each site show general accord (±3 mGy 1 σ), covering mean ranging some 10 less than mGy, representing <1% < 0.1% prescribed treatment site. results uncorrected energy response absorbed greater by factors 1.4, 1.2 1.5 pelvis, neck respectively; corrections have shown elsewhere provide much closer agreement.