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Ambient dose during intraoral radiography with current techniques: Part 1 conversion factor for scattered radiation using a rectangular collimator
摘要： The aim of this study was to establish a conversion factor for assessing the scattered radiation produced during intraoral radiography with a rectangular collimator in areas where the remnant beam is not present. The dose level in the remnant beam will be addressed in another study. A radiological phantom (Rando) in the upright position was exposed to radiation delivered by a Planmeca Intra X-ray unit over 9 exposure geometries (right side of a full mouth series). For each geometry, the scattered radiation dose was measured at 5 locations in the horizontal plane and 4 locations in the vertical plane in front of the patient. The measurements were corrected for background and leakage radiation. An inventory of the distributions of the different geometries with respect to their share of the total workload was created in order to assign the correct weightings of the total ambient scattered radiation for the different geometries. The weightings were used to construct a scattered radiation pattern for a representative mix of exposures. The maximum value found in this pattern was used to arrive at a safe conversion factor. The scattered ambient radiation dose was evenly distributed over the horizontal plane. The scattered ambient radiation dose ranged from 20 to 65% lower in the vertical plane. The conversion factor established for scattered ambient radiation was 0.05 μSv per mAs at 1 meter. This factor is 3-fold lower than the conversion factors reported previously.
关键词： radiation protection,dental radiography,radiation monitoring,Dental Equipment
更新于2025-09-23 15:23:52
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Ambient dose during intra-oral radiography with current techniques: Part 2 quantifying the remnant beam - an <i>in vivo</i> study
摘要： Objectives: (1) To find a safe reference transmission factor for the remnant beam to be used when assessing the remnant beam during intra-oral radiography. (2) To identify factors such as exposure type, side (left or right), gender and age that might significantly affect transmission. Methods: Measurements were performed in the remnant beam during 323 intra-oral exposures of 43 patients. The exposure parameters were 60 kV and 7 mA. These measurements were compared with values in the same setting, but without a patient present to arrive at a transmission value. Differences between types of exposure [bitewing (BW), incisor and canine (IC) periapical, premolar and molar (PM) periapical], exposure side (left or right), gender and age were statistically analysed. The reference value was based on the exposure yielding the highest transmission value, to which a safety margin of two standard deviations (SDs) was added, and then rounding up. Results: The respective mean transmission values (SD) for BW, IC and PM exposures were as follows: 1.78% (1.15%), 0.639% (0.63%) and 2.60% (0.98%). The differences between PM and IC and between BW and IC were significant (p > 0.01). The differences between exposure side, gender and age were not significant. The reference transmission value, which was calculated from the highest mean transmission percentage for PM (2.60%) plus twice the SD (0.98%) and rounding up, was 5%. Conclusions: A transmission factor of 5% could be used to assess the remnant beam during intra-oral radiography. Anterior exposures led to significantly lower transmission values than posterior exposures.
关键词： radiation protection,dental radiography,dental equipment,radiation monitoring
更新于2025-09-23 15:23:52
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A dose monitoring system for dental radiography
摘要： Purpose: The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. Materials and Methods: An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. results: The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. conclusion: A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose. (Imaging Sci Dent 2016; 46: 103-8)
关键词： Radiography,Protection,Radiation monitoring,Radiation,Dental,Radiation Dosage
更新于2025-09-23 15:21:01
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Characterization of Si and SiC detectors for laser-generated plasma monitoring in short wavelength range
摘要： Silicon carbide detectors were employed to characterize the plasma produced by laser interaction with a double stream gas-pu? target source. A 10 Hz repetition rate Nd:YAG laser (1064 nm wavelength, 0.69 J pulse energy and 3 ns pulse duration) was employed to irradiate di?erent gas-pu? targets (Argon, Xenon and Sulfur hexa?uoride), at di?erent pressures (1–10 bar), emitting plasma radiation in di?erent wavelength ranges (ultraviolet, extreme ultraviolet and soft X-rays). The emission produced by the laser radiation was properly ?ltered (employing Titanium, Aluminium, Zirconium and Calcium ?uoride ?lters), to narrow down the broad-band emission of the generated plasma. The SiC detectors’ signals were compared with a calibrated traditional silicon detector evaluating their di?erences, i.e. taking into account the plasma stability, the time trace pro?le and the characteristics of the gas-pu? target source. The obtained results, which will be presented and discussed, allow to improve the geometry and con?guration of the SiC detectors avoiding saturation and charge recombination e?ects and getting a better proportionality to the energy and ?uence of the detected radiations.
关键词： X-ray detectors,Radiation monitoring,Detectors for UV, visible and IR photons,Plasma generation (laser-produced, RF, x ray-produced)
更新于2025-09-23 15:21:01
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Fiber-reading radiation monitoring system using an optical fiber and red-emitting scintillator for ultra-high dose condition
摘要： We have developed a remote scintillation detector using a CCD spectrometer and a red-emitting scintillator coupled with a 20-meters optical fiber for ultra-high-dose condition. Gamma-rays were detected with a conventional deep-red-emitting ruby scintillator and Cs2HfI6 which is a novel material with 700-nm red emission and a high light output. The scintillators were irradiated with gamma-rays from a 60Co source under the effective dose rate from ~0.002 to ~1 kSv/h. The integrated area of the Cs2HfI6 emission spectra was larger than that of the ruby, and the good linearity of Cs2HfI6 signal as a function of dose rate was confirmed.
关键词： radiation monitoring,optical fiber,ruby,ultra-high dose,Cs2HfI6,scintillator
更新于2025-09-23 15:19:57
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The use of optical fibers as passageways for the scintillation light produced in CaF <sub/>2</sub> (Eu) powder in water for low-level tritiated water measurement
摘要： A solid scintillation counting (SSC) system which uses the mixture of CaF2(Eu) powder and tritiated water inside the chamber room will be developed for the measurement of low-level tritiated water. However, the coincidence detection e?ciency and net count rate might be limited by the photon absorption in the chamber of the SSC detector. This paper discusses the feasibility of using light guide ?bers as the optical passageway in the chamber room by Geant4 simulation. The simulation results show that the performance of the detector can be improved by using wavelength-shifting ?bers as optical passageway in the chamber. The detector can maintain a 4.2% coincidence detection e?ciency at a 6 cm chamber thickness, and the detection limit can be as low as 0.47 Bq/mL under 10 min measurement. As a result, using wavelength-shifting ?bers as optical passageways in the chamber room of the SSC system is possible and e?ective.
关键词： Radiation monitoring,Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc),Very low-energy charged particle detectors,Solid state detectors
更新于2025-09-16 10:30:52
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Infrared Bioengineering Feedback Cabin for Recovering Functional Reserves of a Human Organism
摘要： An energy-effective mobile infrared cabin has been developed for activating the functional reserves of a human organism in medicinal, health-improving, and sports practice has been developed. The cabin maintains deep penetration of optical radiation into the tissues of a human being by using near infrared band radiators. The distinctive feature of the facility being proposed is the realization of bioengineering feedback by recording basic physiological indices of the user and automatic control of the infrared procedure parameters based on the results of monitoring. Minimization of thermal load generated by infrared radiators on the user′s organism allows one to expand the sphere of application of the infrared cabin by eliminating the limitations on using it by patients with arterial hypertension and cardiovascular insuf? ciency.
关键词： automatic control,infrared band,physiological indices of a human being,bioengineering feedback,infrared radiation,monitoring,infrared cabin
更新于2025-09-16 10:30:52