This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry. This means that the sensor can be placed directly inside a patient, for example, for brachytherapy treatments, the optical fibres could be placed in the tumour itself or into nearby critical tissues requiring monitoring, via the same applicators or needles used for the treatment delivery thereby providing real-time dosimetric information. The a...

Purpose – The purpose of this paper is to provide a detailed review of radiation dosimetry techniques based on optical fibre dosimeters. It presents a comprehensive bibliography of the current research activities in the area. Design/methodology/approach – A range of published work on optical fibre radiation dosimeters are presented, with the merits and limitations discussed. Each radiation dosimetry technique is discussed in turn, providing examples of dosimeters using such techniques reviewed. The main focus is on gamma radiation although other radiation dosimeters are considered. Findings – This paper provides information on the wide range of research activity into radiation dosimeters. The dose ranges of these dosimeters are presented, along with the advantages and disadvantages of different dosimetry techniques. Originality/value – A comprehensive review of published research in the area of solid radiation dosimetry is presented in this paper. It provides an individual with a review of the various techniques used and most recent research in that field.

Purpose: The purpose of this paper is to provide a comparative review of intensity‐modulated fiber optic sensors with non‐optical sensors for health monitoring applications, from the current research activities in the area.Design/methodology/approach: A range of published research work in sensor design for four different health monitoring applications, including, lumbar spine bending, upper and lower limb motion tracking, respiration and heart rate monitoring, are presented and discussed in terms of their respective advantages and limitations.Findings: This paper provides information on the various types of sensors applied into the health monitoring area. The sensing techniques of the fiber optic sensor for the stated applications are focused and compared in details to highlight their contributions.Originality/value: A comparative review of published work is illustrated in an informative table content, to allow a clear idea of the current sensing approaches for health monitoring applications.

A novel extrinsic optical fiber X-ray dosimeter for biomedical applications is presented in this paper. The primary focus of the sensor is to measure low doses of ionizing X-ray radiation. The material in the sensor tip scintillates upon exposure to radiation and the resultant low level scintillating light is coupled to a polymethylmethacrylate plastic optical fiber, which guides it toward a distant fluorescent optical spectrometer. The optical spectrometer measures the low level scintillating light from the sensor and converts the ionizing radiation energy to measurable arbitrary optical intensity units. Initial testing showed the scintillating optical fiber X-ray dosimeter exhibits an acceptable sensitivity upon excitation from a calibrated X-ray source. Further examinations of the sensor revealed good response and repeatability of measurement for various levels of low energy ionizing X-ray energy. The sensor was found to exhibit a maximum of 3.23% variance from the average value over ten repetitions. The sensor is sensitive from 50 kVp X-ray energy which continued exponentially up to 140 kVp where the response began to taper off. The sensor demonstrated excellent spectral response upon exposure to 6 MV and 15 MV ionizing X-ray radiation energy from a Siemens Avant Garde linear accelerator. It showed excellent repeatability of measurement upon repeated actuation of the radiation over short bursts of time. The sensor demonstrates very good stability of response during on radiation periods, showing a maximum of 2% variation of the full scale value in each case. This type of optical fiber X-ray dosimeter was tested in the University of Limerick (Ireland), the National Institute for Lasers, Plasma and Radiation Physics (Romania), and the Galway Clinic in Ireland. Further investigations were performed by all three facilities to better characterize additional features of the sensor for different X-ray radiation energies.

A novel real-time optical fibre X-Ray dosimeter for monitoring the radiation pulses delivered from a clinical linear accelerator (Linac) is presented. The primary focus of the sensor is to measure low doses of ionising X-ray radiation in real time (limited to 0.1-ms gate time of the detector). The sensor tip material scintillates upon exposure to X-ray energy and the resultant low-level visible light signal is coupled to a polymethyl methacrylate plastic optical fibre, which is used to guide it towards a distal avalanche photodiode-based detector. The detector measures the low-level scintillating light from the sensor, thereby converting the ionizing radiation energy to a measurable signal with a time resolution of 0.1 ms. Results show that the scintillating optical fibre X-ray dosimeter is capable of capturing the individual X-Ray pulses delivered by the Linac during normal operation. Further examination of the results demonstrates that the sensor is capable of measuring dose rate and, hence, dose with a linearity (R ² = 0.9995-0.9999) and in a highly repeatable manner for dose rates in the range 100 to 600 monitor units/min.