Irradiated glass and thermoluminescence yield: Dosimetric utility reviewed
Introduction
Numerous applications in the health sector rely on controlled delivery of incident energy, present focus being on the harnessing of luminescence from irradiated glass-based dosimeters. Review is made herein of developments that have directly contributed to the thermoluminescence work that has been recently presented at ICDA-3 by the group of Bradley, exploring prospects for future utilisation of glass-based systems. Examples of prominent challenges include: tumour therapeutics, maximising target dose while preserving surrounding healthy tissue (IAEA, 2016); radiosurgery, offering fine-beam scalpel-like spatial acuity (to within 1 mm); image-guided radiology interventions; radionuclide theranostics, combining diagnosis and therapy. Apparent is the dependency on source type, configuration and collimation, the emissions interacting in tissue, thereby depositing dose. Of particular note are the several advances in dose delivery that are placing ever increasing demands on the systems of dosimetry; consider for instance accommodating the spatial resolution needs of say small field in vivo dosimetry in an aqueous medium at high dose-rates. The glass-based TL systems offer attractions that include the robust nature of the medium, their impervious nature both to water and the EMF of MRI-guided linacs, also acknowledging the high spatial resolutions that can be attained.
In the therapeutic regime, discrepancy in radiation delivered to the target can have highly adverse effects, the QA responsibilities being obvious. In this and other examples within radiation medicine, there is continuing need for enhanced accuracy and precision in the delivery and measurement of the optimum radiation dose. As with any other form of radiation dosimetry, developments towards utilising the luminescence yield of irradiated glass entails quantitative methods in determining the energy deposited within the medium (Attix, 1986).
Section snippets
Choices in dosimetry
In regard to the choices confronting the user, the many possibilities are far too great to cover in detail in any one short review. However, the more striking issues can best be illustrated through consideration of the most prominent of radiation monitoring devices, namely the ionization chamber (IC). The IC, regarded as the ‘gold standard’ quality assurance (QA) instrument throughout the realm of radiation medicine, utilizes relatively high voltages (i.e. several hundred or more), precluding
The luminescence of glass-based media
Media such as insulators and semi-conductors have the important ability to retain part of the absorbed radiation, metastable states being of the form of traps of electron-hole pairs, subsequently to be released (following stimulation) in forms that include infrared/visible light or ultraviolet (UV) light, otherwise referred to as luminescence. Luminescence comprises of the phenomenon of fluorescence and phosphorescence, both dependent on time delay between stimulation and light emission (Jarnet
The basis of Ge-doped SiO2 optical fibre TLDs
Ge-doped SiO2 optical fibres (also variously doped glass beads) are in active development, with numerous published TL investigations (see for instance, Benabdesselam et al., 2013a,b; Bradley et al., 2014; Jafari et al., 2014a, Jafari et al., 2014b; Nawi et al., 2015; Bradley et al., 2015, 2016). The basis of the luminescence is underpinned by molecular structure and composition, with the various associated trapping centres and activation energy reviewed by Bradley et al. (2012). SiO2, be it
Developments in fabrication of silica-based thermoluminescence dosimeters
As inferred, over the past three years we have been exploring the association between design and performance of silica-based media. Our efforts stemmed from the earlier adventitious use of commercially available Ge-doped single mode telecommunication fibres (SMF) in such applications, the design of these being entirely unrelated to the needs to which the fibres were put (see for instance, Hashim et al., 2010). The SMFs, as well as other telecommunication fibres such as multi-mode fibres (MMF,
The use of Ge-doped SiO2 optical fibre TLDs
The use of commercially available Ge-doped SiO2 optical fibres as dosimeters, with spatial resolution down to the order of 100 μm have been discussed by Rahman et al. (2012), representing a non-tissue equivalent Bragg-Gray cavity. The potential of Ge-doped SiO2 optical fibres and glass beads for particular application in small-field radiotherapy dosimetry has been researched by a number of authors (Benabdesselam et al., 2013a,b; Jafari et al., 2014a, Jafari et al., 2014b; Bradley et al., 2017;
Conclusions
The work represented herein is the result of a great many efforts by numbers of researchers; the glass fabrications work in itself derives from the work of a large collaborative group, centred on the University of Surrey and the University of Malaya. The push has been towards controlling the various influences and issues that guide the effective development of silica based media as TLDs. In particular, we have discussed fabrication issues and how these can influence defect types and
Declaration of competing interest
The authors have no conflict of interests to report.
References (53)
- et al.
A preliminary analysis of LET effects in the dosimetry of proton beams using PRESAGETM and optical CT
Appl. Radiat. Isot.
(2009) - et al.
Assessment of Ge-doped optical fibre as a TL-mode detector
J. Non-Cryst. Solids
(2013) - et al.
Review of doped silica glass optical fibre: their TL properties and potential applications in radiation therapy dosimetry
Appl. Radiat. Isot.
(2012) - et al.
Development of tailor-made silica fibres for TL dosimetry
Radiat. Phys. Chem.
(2014) - et al.
Enhancing the radiation dose detection sensitivity of optical fibres
Appl. Radiat. Isot.
(2015) - et al.
Latest developments in silica-based thermoluminescence spectrometry and dosimetry
Appl. Radiat. Isot.
(2016) - et al.
Towards the development of doped silica radioluminescence dosimetry
Radiat. Phys. Chem.
(2019) - et al.
Thermoluminescence response of Ge-doped SiO2 fibres to electrons, X- and γ-radiation
Radiat. Phys. Chem.
(2016) - et al.
The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons
Appl. Radiat. Isot.
(2010) - et al.
Low-cost commercial glass beads as dosimeters in radiotherapy
Radiat. Phys. Chem.
(2014)
Mailable TLD system for photon and electron therapy beams
Int. J. Radiat. Oncol. Biol. Phys.
Investigation on various types of silica fibre as thermoluminescent sensors for ultra-high dose radiation dosimetry
Sens. Actuators A Phys.
Radiotherapy dosimetry and the thermoluminescence characteristics of Ge-doped fibres of differing germanium dopant concentration and outer diameter
Radiat. Phys. Chem.
Characterization of amorphous thermoluminescence dosimeters for patient dose measurement in X-ray diagnostic procedures
Radiat. Phys. Chem.
Ge and B doped collapsed photonic crystal optical fibre, a potential TLD material for low dose measurements
Radiat. Phys. Chem.
Isoelectronic series of twofold coordinated Si, Ge, and Sn atoms in glassy SiO 2: a luminescence study
J. Non-Cryst. Solids
Low-dose photon irradiation response of Ge and Al-doped SiO2 optical fibres
Appl. Radiat. Isot.
Optically stimulated luminescence of magnesium aluminate (MgAl2O4) spinel
Radiat. Meas.
Preliminary results on the photo-transferred thermoluminescence from Ge-doped SiO2 optical fiber
Radiat. Phys. Chem.
Gamma and X‐Ray Interactions in Matter, Introduction to Radiological Physics and Radiation Dosimetry
Performance of Ge-doped optical fiber as a thermoluminescent dosimeter
IEEE Trans. Nucl. Sci.
Doped silica fibre thermoluminescence measurements of radiation dose in the use of 223Ra
Appl. Radiat. Isot.
Theory of Thermoluminescence and Related Phenomena
Optical transitions of paramagnetic Ge sites created by x-ray irradiation of oxygen-defect-free Ge-doped SiO 2 by the sol-gel method
Phys. Rev. B
Near-UV photosensitivity of germanosilicate glass: application for fiber grating fabrication
Thermoluminescence response of Ge-doped cylindrical-, flat-and photonic crystal silica-fibres to electron and photon radiation
PLoS One
Cited by (14)
Luminescence characterization of BioGlass undoped and doped with europium and silver ions
2023, Applied Radiation and IsotopesGe-doped silica optical fibre for Time Resolved Radiation Dosimetry
2021, Radiation Physics and ChemistryCitation Excerpt :For linearity, each fibre was exposed to a range of doses (25, 50, 100, 200, and 400 cGy), as typically obtained during the course of external beam fractionation, RL response being recorded. Each radiation dose has been obtained in an exposure time of 40s, this being achieved by varying the dose rate for the respective dose (Almond and Biggs, 1999; Bradley et al., 2020). Thus for example, for a dose rate of 600 cGy/min, the corresponding dose to achieve in 40 s duration is 400 cGy.
Characterization of a promising luminescence-based graphite radiation dosimeter
2021, Radiation Physics and ChemistryCitation Excerpt :The latter indicate traps distribution, with the energy levels of these identified via the sample temperature, each peak intensity being correlated with the associated defect density (Booth, 1954). The trap parameters determine the kinetics of the trap centres (Toktamis and Yazici, 2012; Bakr and Omer, 2020; Wahib et al., 2020), the glow curve shape being influenced by the nature and number of impurities, lattice defects in the case of crystalline material (Bradley et al., 2020a,b), as well as the thermal background and material treatment. With the assumption that the heating rate remains constant during the period of capture of the dosimetric peaks the relative amplitudes of these provide approximations of the relative population of trapped electrons.
Passive dosimetry of β-irradiated lithium borate doped glass
2021, Optical MaterialsRadioluminescence of cylindrical and flat Ge-doped silica optical fibers for real-time dosimetry applications
2021, Applied Radiation and IsotopesCitation Excerpt :Conversely, in the case of the cylindrical fibers (CF) an over-response is most apparent at the greatest dose rate, better approximating that of the IC at lower dose-rates. The capacitive response, most noticeable for the flat fibers, results from the greater propensity for deep traps induction during the FF fabrication process (Begum et al., 2018; Bradley et al., 2020). This is made apparent in respect of parallel work on thermoluminescence (TL) dosimetry, FF being able to retain trapped energy for a longer period, as evident from the fading rate (Rahim et al., 2017).