title: Preliminary evaluation of implantable MOSFET radiation dosimeters.
abstract: In this paper, we report on measurements performed on a new prototype implantable radiation detector that uses metal-oxide semiconductor field effect transistors (MOSFETs) designed for in vivo dosimetry. The dosimeters, which are encapsulated in hermetically sealed glass cylinders, are used in an unbiased mode during irradiation, unlike other MOSFET detectors previously used in radiotherapy applications. They are powered by radio frequency telemetry for dose measurements, obviating the need for a power supply within each capsule. We have studied the dosimetric characteristics of these MOSFET detectors in vitro under irradiation from a 60Co source. The detectors show a dose reproducibility generally within 5% or better, with the main sources of error being temperature fluctuations occurring between the pre- and post-irradiation measurements as well as detector orientation. A better temperature-controlled environment leads to a reproducibility within 2%. Our preliminary in vitro results show clearly that true non-invasive in vivo dosimetry measurements are feasible and can be performed remotely using telemetric technology.
authors.affiliation: Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. abeddar@mdanderson.org
authors.forename: A S
authors.initials: AS
authors.lastname: Beddar
authors.forename: M
authors.initials: M
authors.lastname: Salehpour
authors.forename: T M
authors.initials: TM
authors.lastname: Briere
authors.forename: H
authors.initials: H
authors.lastname: Hamidian
authors.forename: M T
authors.initials: MT
authors.lastname: Gillin
mesh_terms: D002138:Calibration; D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design / Q000379:methods*; D005069:Evaluation Studies as Topic; D005373:Film Dosimetry / Q000379:methods; D006801:Humans; D019047:Phantoms, Imaging; D011137:Polystyrenes; D011846:Radio Waves; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D012666:Semiconductors; D013686:Telemetry; D013696:Temperature; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D003037:Cobalt Radioisotopes; D011137:Polystyrenes