New Developed Cylindrical TM010 Mode EPR Cavity for X-Band In Vivo Tooth Dosimetry

Abstract

EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity’s cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry.

Detection of electron spin resonance down to 10 K using localized spoof surface plasmon

“…They are used in commercial [13] and home built ESR spectrometers [14] to achieve high sensitivity. In these resonators, either transverse electric [15] or transverse magnetic [16] modes are excited for the creation of a microwave magnetic field at the sample's location. For pulsed ESR spectrometers, resonators with a low quality factor are preferable to achieve a short ring-down time and thus faster response time of the spectrometer [10].…”

Electron spin resonance (ESR) dose measurement in bone of Hiroshima A-bomb victim

“…The third inter-comparison, finalized in 2006, demonstrated that ESR tooth dosimetry can detect doses as low as ~100 mGy [ 8 ]. Therefore, this technique is useful for the triage of victims, and it can help to define the best possible treatment for such victims [ 9 , 10 ].…”

Flexible, Wireless, Inductively Coupled Surface Coil Resonator for Epr Tooth Dosimetry

“…Given this general summary of the intended measurement conditions and scenario, the ideal resonator would have the following characteristics: The sensing component of a conventional L-band (1.2 GHz) EPR spectrometer typically consists of a surface coil resonator with a coupler that is rigidly, physically attached to the other components of the EPR spectrometer (6)(7)(8)(9) , which can result in bulky and cumbersome operation, limitations in samples and sites that can be measured, reduction in sensitivity and hinder the overall performance and utility of the spectrometer. Other EPR resonators for measuring human teeth also have physical dimensions that hinder proper in vivo measurements (10,11) . This resonator eliminates the need for the measurement sample (in the case of EPR tooth dosimetry: the measurement subject and their tooth) to be physically and electrically connected to the coupler of the EPR spectrometer.…”