The design of X-band EPR cavity with narrow detection aperture for in vivo fingernail dosimetry after accidental exposure to ionizing radiation

Abstract

For the purpose of assessing the radiation dose of the victims involved in the nuclear emergency or radiation accident, a new type of X-band EPR resonant cavity for in vivo fingernail EPR dosimetry was designed and a homemade EPR spectrometer for in vivo fingernail detection was constructed. The microwave resonant mode of the cavity was rectangular TE101, and there was a narrow aperture for fingernail detection opened on the cavity’s wall at the position of high detection sensitivity. The DPPH dot sample and the fingernail samples were measured based on the in vivo fingernail EPR spectrometer. The measurements of the DPPH dot sample verified the preliminary functional applicable of the EPR spectrometer and illustrated the microwave power and modulation response features. The fingernails after irradiation by gamma-ray were measured and the radiation-induced signal was acquired. The results indicated that the cavity and the in vivo EPR dosimeter instrument was able to detect the radiation-induced signal in irradiated fingernail, and preliminarily verified the basic function of the instrument and its potential for emergency dose estimate after a radiation accident.

Contribution of Biological and EPR Dosimetry to the Medical Management Support of Acute Radiation Health Effects

“…Additionally, EPR data have been collected after incorporation of radionuclides leading to an internal dose component, which can also be detected, e.g., by teeth enamel. These studies examined the intake of 239,240 Pu, 137 Cs and 98,90 Sr by the populations living around the Semipalatinsk test site [75][76][77] as well as the intake of 89,90 Sr and 137 Cs by the population living near the Techa River [78,79]. However, EPR was shown to be most applicable when radionuclides are distributed homogenously in the body [80].…”

“…Additionally, the establishment of calibration curves is challenging, because significant doses are needed at the point of interest and thus only total body irradiated cancer patients can be used, which are rare. Phantoms, which, e.g., were used for investigation of influences on measurements in in vivo setups [89,90], are also no option, because they are not standardized and validated yet. Nevertheless, some work on in vivo EPR measurement already exists.…”

Enhancing Precision in L-band Electron Paramagnetic Resonance Tooth Dosimetry: Incorporating Digital Image Processing and Radiation Therapy Plans for Geometric Correction

“…Q-band EPR tooth dosimetry is a potentially useful method due to its rapid analysis time and minimal biopsy requirements, although it may cause irreversible damage to the tooth and is susceptible to inaccuracies from heterogeneous dose distributions in accident scenarios (Romanyukha et al 2014). The emerging X-band in vivo EPR spectrometer also shows potential for nail and tooth dosimetry (Guo et al 2021a and b) but is more sensitive than the L-band to humidity changes within the mouth. Therefore, L-band in vivo tooth dosimetry remains an appealing option for triage in large-scale radiation events, given improvements in the minimal detectable dose and dosimetric precision to meet triage criteria.…”

Development of Electron Paramagnetic Resonance Magnet System for In Vivo Tooth Dosimetry

“…us, most in vivo studies chose low frequencies around 1 GHz to avoid the interference of water [5,9]. Some scholars tried using X-band frequency for in vivo tooth dosimetry together with a modified X-band resonator [10,11]. Owing to the lack of commercially available spectrometers for human studies, specific devices have to be developed for in vivo studies aiming at human applications.…”

“…Hirata et al [12] developed an electronically tunable resonator for in vivo EPR measurement. Guo et al [10,11] also developed a resonator to measure only in vivo tooth dosimetry using X-band.…”