Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Oral and maxillofacial radiologyAssessment of radiation exposure in dental cone-beam computerized tomography with the use of metal-oxide semiconductor field-effect transistor (MOSFET) dosimeters and Monte Carlo simulations
Section snippets
Phantom
An anthropomorphic RANDO RAN102 male head phantom (Radiation Analogue Dosimetry System; Phantom Laboratory, Salem, NY, USA) was used for the dose measurements. The phantom comprises a human skull embedded in a soft tissue–equivalent material to match the attenuation and scattering conditions of the bone, soft tissues, and airways of the human head. The phantom consists of 10 25-mm-thick layers numbered from 0 to 9 in the order from the calvaria to the neck area (Figure 1). Each layer has a grid
MOSFET dose measurements
The imaging volume (dental area) used for the MOSFET dose measurements ranged from the tip of the chin to the sinuses (Zref 83 cm) and is shown in Figure 3.
The effective dose in the 8 × 8 cm FOV imaging volume using the standard clinical parameters (84 kV, 12 mA, 145 mAs) was 153 μSv. The major contributions (wTHT) to the effective dose originated from the remainder tissues (32%), salivary glands (21%), and thyroid gland (21%). The greatest contributors to the effective dose in the remainder
Discussion
A novel mobile MOSFET dosimetry device was used to determine organ and effective dose in the maxillofacial area using an anthropomorphic RANDO head phantom as the patient model. The purpose was also to compare the experimental MOSFET results with Monte Carlo simulations.
In an earlier study, Qu et al.24 performed organ dose and effective dose measurements with the Promax 3D CBCT device using 8 × 8 cm FOV, 84 kV, 12 mA, 12 s, and 21 thermoluminescent dosimeters. Interestingly, our MOSFET
Conclusion
Taking into account the uncertainties in both systems, the MOSFET dosimeters placed in a RANDO phantom gave results similar to the Monte Carlo simulations. The MOSFET dosimeters constitute a feasible method for the dose assessment of CBCT units in the maxillofacial region and offer a very fast readout possibility compared with very time-consuming TLD sensors.
References (24)
- et al.
Effective dose range for dental cone beam computed tomography scanners
Eur J Radiol
(2012) - et al.
Comparison between effective radiation dose of CBCT and MSCT scanners for dentomaxillofacial applications
Eur J Radiol
(2009) - et al.
Comparative dosimetry of dental CBCT devices and 64-slice CT for oral and maxillofacial radiology
Oral Surg Oral Med Oral Pathol Oral Radiol Endod
(2008) - et al.
Effective radiation dose of promax 3D cone-beam computerized tomography scanner with different dental protocols
Oral Surg Oral Med Oral Pathol Oral Radiol Endontology
(2010) - et al.
Dosimetry of two extraoral direct digital imaging devices: NewTom cone beam CT and Orthophos plus DS panoramic unit
Dentomaxillofac Radiol
(2003) - et al.
Effective dose from cone beam CT examinations in dentistry
Br J Radiol
(2009) - et al.
Dosimetry of 3 CBCT units for oral and maxillofacial radiology
Dentomaxillofac Radiol
(2006) - et al.
Dosimetry and image quality of four dental cone beam computed tomography scanners compared with multislice computed tomography scanners
Dentomaxillofac Radiol
(2009) - Kim S, Sopko D, Toncheva G, Enterline D, Keijzers B, Yoshizumi TT. Radiation dose from 3D rotational x-ray imaging:...
- et al.
Estimating effective dose to pediatric patients undergoing interventional radiology procedures using anthropomorphic phantoms and MOSFET dosimeters
AJR Am J Roentgenol
(2010)
Radiation dose from cone beam CT in a pediatric phantom: risk estimation of cancer incidence
AJR Am J Roentgenol
Estimation of absorbed doses from paediatric cone-beam CT scans: MOSFET measurements and Monte Carlo simulations
Radiat Protect Dosim
Cited by (41)
Impact of thyroid gland shielding on radiation doses in dental cone beam computed tomography with small and medium fields of view
2022, Oral Surgery, Oral Medicine, Oral Pathology and Oral RadiologyCitation Excerpt :The phantom head was placed orthogonally to the detector plane of the CBCT unit and its position was confirmed by laser beams. To measure absorbed doses, 20 metal oxide semiconductor field-effect transistor (MOSFET) dosimeters (TN-RD-70-W20, Best Medical Canada, Ottawa, ON, Canada), calibrated at the Secondary Standard Dosimetry Laboratory, were positioned in the layers of the male phantom head in accordance with the protocol of Koivisto et al.36 (Table I). These positions represented organs and tissues known to be sensitive to radiation as listed in the International Commission on Radiological Protection (ICRP) Publication 103, issued in 200737 (Table II).
Dental cone beam CT: An updated review
2021, Physica MedicaCitation Excerpt :Effective and organ doses have been determined using thermoluminescent dosimeters (TLD), optically stimulated luminescence (OSL) dosimeters, and metal–oxidesemiconductor field-effect transistor (MOSFET) detectors [53–55]. Recent studies have also used Monte Carlo simulations to estimate effective and organ doses [53,55–57]. The magnitudes of these biological dose quantities vary remarkably in dental CBCT depending on the FOV size, positioning, and exposure parameters.
Influence of patient position and other inherent factors on image quality in two different cone beam computed tomography (CBCT) devices
2017, European Journal of Radiology OpenComparison of dosimetry methods for panoramic radiography: Thermoluminescent dosimeter measurement versus personal computer-based Monte Carlo method calculation
2016, Oral Surgery, Oral Medicine, Oral Pathology and Oral RadiologyDental cone beam CT: A review
2015, Physica MedicaCitation Excerpt :In addition to mammography, where organ doses are already implemented by mean glandular dose readings provided by modern digital mammography equipment [59–61], dental CBCT could be another modality driver of automatic organ dosimetry, as the X-ray beam in dental CBCT is applied to a relatively constant maxillofacial anatomy with a more certain delineation of exposed organ coverage. Morant et al. [62] and Koivisto et al. [40] have already proved the accuracy of Monte Carlo simulations for the dental organ dose evaluations. The MC code adapted to dental CBCT could provide an effective automatic tool for assessing patient specific organ doses in the future.
Assessment of protocols in cone-beam CT with symmetric and asymmetric beams usingeffective dose and air kerma-area product
2015, Applied Radiation and Isotopes
This project was supported by Planmeca Oy. Juha Koivisto is an employee of Planmeca Oy.