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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 5  |  Issue : 1  |  Page : 39-46

Radiation dose measurements in intraoral and panoramic dental radiography in the Southern Region of Saudi Arabia


1 Department of Radiological Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
2 Department of Radiological Sciences, Applied Medical Sciences College, Najran University, Najran, Saudi Arabia
3 Radiology Department, KMGH, Khamis Mushayt, Saudi Arabia
4 Department of Radiological Science, Colleges of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
5 Department of Diagnostic Sciences & Oral Biology, College of Dentistry, King Khalid University, Abha, Saudi Arabia
6 Departments of Pediatric Dentistry and Orthodontic Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia
7 Diagnostic radiology department, Applied Medical Sciences College, Jazan University, Saudi Arabia

Date of Web Publication13-Aug-2020

Correspondence Address:
Mohammed S Alqahtani
Department of Radiological Sciences College of Applied Medical Sciences King Khalid University, Abha
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/WKMP-0204.291958

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  Abstract 


Objective: This study aims to estimate patient radiation doses for intraoral and panoramic dental radiography in the southern region of Saudi Arabia. Material and Methods: For intraoral units, the radiation doses were measured in terms of incident air kerma, Ki, and the detector was placed at 50 cm from the focus point. For panoramic dental radiography, the radiation doses were measured in terms of air Kerma-area product, PKA, using a calibrated CT ionization chamber. Results: For intraoral, the values for the estimated incidence of air kerma, Ki, ranged from 1.25 to 4.61 mGy (average: 2.55 mGy). For panoramic, the values for estimated Kerma-area product, PKA, values ranged from 79.5 to 122.1 mGy.cm2 (average: 99 mGy.cm2) for adults and ranged from 43.3 to 80.2 mGy.cm2 (average: 58.5mGy.cm2) for paediatrics. Conclusion: The study’s outcomes were compared with previous studies from other countries, indicating similar or slightly higher values. These results could serve as baseline data for radiation protection optimization and the development of national diagnostic reference levels in Saudi Arabia.

Keywords: Intraoral and panoramic dental radiography, Kerma-area product (PKA), Incident air kerma (kj), Radiation Protection


How to cite this article:
Almohiy HM, Hussein KI, Alqahtani MS, Saeed MK, Hassan E, M. Asiri AA, Saad M, Mukhtar EM, Adam M, Alshahrani M, Alsleem HA, Ajmal M, Alshahrani I, Abuhadi N. Radiation dose measurements in intraoral and panoramic dental radiography in the Southern Region of Saudi Arabia. King Khalid Univ J Health Scii 2020;5:39-46

How to cite this URL:
Almohiy HM, Hussein KI, Alqahtani MS, Saeed MK, Hassan E, M. Asiri AA, Saad M, Mukhtar EM, Adam M, Alshahrani M, Alsleem HA, Ajmal M, Alshahrani I, Abuhadi N. Radiation dose measurements in intraoral and panoramic dental radiography in the Southern Region of Saudi Arabia. King Khalid Univ J Health Scii [serial online] 2020 [cited 2020 Oct 26];5:39-46. Available from: https://www.kkujhs.org/text.asp?2020/5/1/39/291958




  Introduction Top


Patient dose measurements and protecting patients from radiation during diagnostic procedures are of great concern and have been a critical research area since the introduction of radiological x-ray procedures.[1],[2],[3],[4],[5],[6] The fundamental principles of radiation protection are the justification, optimization and dose limitation of occupation exposed workers.

Optimizing radiation protection for diagnostic radiology requires the application of patient-specific imaging protocols in addition to dose estimation for the different imaging procedure. Procedure-specific diagnostic reference levels (DRLs) constitute the recommended dose parameters for monitoring and optimizing of radiation protection in the medical and dental fields.[6]

For radiography, the most common dose metrics used for DRLs are the entrance surface air kerma (ESAK), and Kerma area product (PKA). The incident air kerma (K,-,) is the air kerma measured at the end of the spacer, or director, cone without backscatter objects in the beam [7, 8]. The PKA for intraoral dental radiography is defined as the Ki, multiplied by the beam area defined by the spacer, or director, cone.[7],[8] For panoramic examinations, the PKA is defined as air kerma-length product multiplied by the height of the x-ray beam.[7],[8]

As mentioned by the Internal Atomic Energy Agency (IAEA) the diagnostic reference doses for adults are in the range between 84 to 120 mGy.cm2, in terms of kerma-area product, for panoramic dental radiography, and in the range between 0.65 to 3.7 mGy, in terms of entrance surface air kerma, for intraoral dental radiography.[2]

Several studies have been conducted on dose measurements in panoramic and intraoral dental radiography.[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21] These studies have shown wide variations for patient doses performed at different facilities. The diagnostic reference doses for intraoral were in the range between 0.4 to 11 mGy for both paediatric and adult patients. These studies also reported PKA values in the range between 60 to 120 mGy.cm2 for paediatric and adult patients.

To date, no studies have been published regarding measuring and comparing radiation doses for intraoral and panoramic dental radiography in southern Saudi Arabia. Thus, this study aims to estimate patient radiation doses for intraoral and panoramic dental radiography in southern Saudi Arabia. The measured doses will serve as a baseline data for optimization of the radiation protection and contribute to the development of national diagnostic reference levels in Saudi Arabia.


  Material and Methods Top


Five panoramic and eight intraoral dental radiographic units were selected for dose measurements. The study was carried out at dental clinics of the College of Dentistry, King Khalid University and dental clinics of the College of Dentistry, Najran University. [Table 1] and [Table 2] show available technical information for the intraoral and panoramic X-ray machines respectively, also information such as manufacturer, model, modality and country of origin are tabulated as well.
Table 1: Characteristics of the intraoral dental units

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Table 2: Characteristics of the panoramic dental units

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Radiation Dose measurements

For intraoral units, dose measurements were taken using an Unfors Xi dosimeter (Unfors Inc., Bildal, Sweden), last calibrated on 20 August 2018. Measurements were taken according to the procedure recommended by IAEA TRS 457 for intraoral dental radiography.[8] The radiation doses were measured in terms of incident air kerma, Ki, and the detector was placed at a distance of 50 cm from the focus point – this is known as focus-to-detector distance (FDD) - with the sensitive volume of the detector entirely covered by the primary X-ray beam. There were no scattering objects nearby in the beam, as recommended.[8] The measured doses were corrected for focus-skin distance (FSD) at the centre of the spacer cone’s exit using the following equation:



Where describes measured incident air kerma at 50 cm FDD.

The clinical setup technique factors of tube voltage (kVp) range (60–70) and tube current (mA) range (0.4–4.5) were used to measure reference doses.

For panoramic dental radiography, the radiation doses were measured in terms of air Kerma-area product, PKA, which can be calculated using the following equation:[8]



Where H (cm) is the height of the X-ray beam at the secondary slit, measured using X-ray radiography film, and (mGy.cm) is the air kerma-length product.

These were measured using a calibrated CT ionization chamber (X2 CT, SN: 252154, RaySafe, Sweden), last calibrated on 16 February 2018 (eff. length ~10 cm), connected to an electrometer (RaySafe, Sweden). The CT chamber was placed in front of the secondary collimator (Slit), at the centre of the slit and perpendicular to its length. The clinical setup technique factors of tube voltage (kVp) range (63–72) and tube current-exposure time product (mAs) range (5–11) were used to measure reference doses.[8]


  Results Top


[Table 3] shows results of the measurement of incident air kerma, KFDD, at 50 cm FDD and the calculated incident air kerma, Ki, for the intraoral units. Also included are exposure parameter (tube current and tube voltage) and FSD values. Measurements were taken with tube voltage (kV) settings ranging from 60 to 70, tube currents-exposure time product (mAs) ranging from 0.4 to 4.5, and FSD ranging from 60 to 300 mm. [Table 3] presents the incident air kerma, Ki, values, which ranged from 1.25 to 4.61 mGy (average: 2.55 mGy). [Figure 1] shows the calculated incident air kerma, Ki, for intraoral units, along with its distribution. The Ki values for direct digital radiography units can be observed to have been lower than the values of conventional screen-film (SF) units.
Table 3: Exposure parameters, FSD and Ki values measured for adult and paediatric patients undergoing intraoral examinations

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Figure 1: Bar chart shows the distribution of the calculated incident air kerma values, Ki, for intraoral dental radiographic units

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[Table 4] provides the measured air kerma-length product, and the calculated Kerma-area product, PKA, for the panoramic units, along with exposure parameter values (tube current, tube voltage, and exposure time) and beam heights (H). Measurements were taken with tube voltage settings ranging from 63 to 72 kVp, tube currents ranging from 5 to 11 mAs, and exposure time ranging from 11 to 20 s. As shown in [Table 4], the estimated Kerma-area product, PKA, values ranged from 79.5 to 122.1 mGy.cm2 (average: 99 mGy.cm2) for adults and from 43.3 to 80.2 mGy.cm2 (average: 58.6mGy.cm2) for paediatrics. [Figure 2] shows the range of the measured air kerma-length product, , and the calculated Kerma-area product, PKA, for panoramic units. The kerma-length product , and the calculated Kerma-area product, PKA, values can be observed to have been lower for paediatrics than for the adults.
Table 4: Exposure parameters, H and PKA values measured for adult and paediatric patients undergoing panoramic examinations

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Figure 2: Box plots illustrate the distribution of the measured air kerma-length product (A) and the calculated Kerma-area product (B) for panoramic dental radiographic units

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The intraoral radiography dose values obtained in this study were compared with those reported in studies in Cyprus,[16] Greece,[17] Sudan[18] and Japan;[20] [Figure 3] shows this comparison. The panoramic radiography dose values obtained were then compared with values reported by studies in Kosovo,[19] Sudan[18] and France,[21] and Germany;[12] [Figure 4] shows this comparison.
Figure 3: Bar chart shows a comparison of the intraoral reference dose levels reported in this study with those from studies in Cyprus,[16] Greece,[17] Sudan[18] and Japan[20]

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Figure 4: Bar chart shows a comparison of the panoramic reference dose levels reported in this study with those from studies in Kosovo,[19] Sudan[18] and France,[21] Germany[12]

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  Discussion Top


Radiography procedures play vital roles in the process of diagnosing and treating a broad range of dental cases. The validation and radiation assessment for such equipment needs to be conducted and standardized. This study evaluated the DRLs for a variety of commercially available radiographic dental units. The quantities that have been studied were incident air kerma, Ki, kerma-area product, PKA, and kerma-length product, PKL. The data produced has been compared with data from various geographical regions, including Cyprus, Sudan, Japan, Greece, France, and Germany.[12],[16],[17],[18],[19],[20],[21]

This study recorded PKA values comparable to those reported in the literature.[18],[19],[21] For instance, the variation between the average recorded PKA value and the maximum recommended value was 2.83 per cent for panoramic radiographic units. Nevertheless, a substantial variation was noted for Ki measurements, with average Ki values 24.18 per cent higher than the recommended values for intraoral radiographic procedures.

The study also evaluated the difference between delivered doses for adults compared to paediatrics using various imaging protocols and equipment. The PKA values for the adult protocols were 52.12 per cent higher than those for the paediatric protocols. For panoramic equipment, the recorded PKL values for paediatric protocols were 50.08 per cent lower than the values for the adult protocols. In addition, the average recorded PKA for adult protocols was 2.58 per cent lower than the values reported in the literature [16] and slightly higher than other.[12],[17],[18],[20]

This study’s outcomes were compared with previous studies from other countries, indicating similar or slightly higher values; it is hoped that this would encourage radiation protection officials in dental centres in southern Saudi Arabia to establish comprehensive, evidence-based protocols for dose optimization. Furthermore, continuous assessment of the dental radiographic units should be conducted, especially for intraoral radiographic equipment, to trace changes to doses delivered to both patients and clinical practitioners. A comprehensive action plan would include clear dose optimization protocols and intensive radiation protection training sessions; such a plan would reflect positively on the dental services provided.


  Conclusion Top


Dose measurements in intraoral and panoramic dental radiography play an essential role in optimizing patient dose for radiation protection purposes. Precise evaluation of the radiation dose delivered should be conducted for different dental radiographic units to improve the radiation awareness of the medical practitioners in those departments.

The measured radiation doses for intraoral and panoramic dental radiography obtained in this study compare well with the results presented in the literature. The results could serve as baseline data for radiation protection optimization and the development of national diagnostic reference levels in Saudi Arabia.

Conflict of Interest: None



 
  References Top

1.
International Commission on Radiological Protection. The 2007 recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann ICRP. 2007; 37:2-4.  Back to cited text no. 1
    
2.
Radiation doses in dental radiology, Internal Atomic Energy Agency (IAEA). Available at: https://www.iaea.org/resources/rpop/health-professionals/dentistry/radiation-doses. Accessed 12 May 2020.  Back to cited text no. 2
    
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International Atomic Energy Agency (IAEA). Safety Standards. Safety Series No. 115. IAEA, Vienna. 1996.  Back to cited text no. 3
    
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ICRP. International Commission on Radiological Protection Radiation and your patient: a guide for medical practitioners. Diagnostic reference levels in medical imaging. ICRP Supporting Guidance 2. Ann ICRP. 2001;31:4.  Back to cited text no. 4
    
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ICRP. ICRP publication 73: radiological protection and safety in medicine. Ann ICRP. 1996; 26(2).  Back to cited text no. 5
    
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Leitz W, Gron P, Servomaa A, Einarsson G, Olerud H. Nordic working group for medical x-ray diagnostics: diagnostic reference levels within x-ray diagnostics - experiences in the Nordic countries. In: Paile W, editor. Radiation protection in the 2000s – Theory and practice; Nordic society for radiation protection: Proceedings of the XIII ordinary meeting; August 25-29, 2002; Turku/Åbo, Finland. Helsinki: Radiation and Nuclear Safety Authority; 2003; pp. 256-261.  Back to cited text no. 6
    
7.
Napier ID. Reference doses for dental radiography. Br Dent J. 1999; 186:392-396.  Back to cited text no. 7
    
8.
International Atomic Energy Agency (IAEA). Dosimetry in Diagnostic Radiology: An International Code of Practice. Technical Reports Series No. 457. IAEA, Vienna. 2007; 209-220.  Back to cited text no. 8
    
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Wall BF. Radiation protection dosimetry for diagnostic radiology patients. Radiat Prot Dosimetry. 2004; 109: 409-419.  Back to cited text no. 9
    
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Tierris CE, Yakoumakis EN, Bramis GN, Georgiou E. Dose area product reference levels in dental panoramic radiology. Radiat Prot Dosim. 2004; 111(3):283-287.  Back to cited text no. 10
    
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Helmrot E, Alm Carlsson G. Measurement of radiation dose in dental radiology. Radiat Prot Dosim. 2005; 114(1-3): 168-171.  Back to cited text no. 11
    
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Poppe B, Looe HK, Pfaffenberger A, Chofor N, Eenboom F, Sering M, Rühmann A, Poplawski A, Willborn K. Dose-area product measurements in panoramic dental radiology. Radiation Protection Dosimetry. 2006; 1- 4.  Back to cited text no. 12
    
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Harata Y, Sakaino R, Okano T, Sato K, Yosue T, Nishikawa K, et al. Diagnostic reference level of dental radiography in Japan. Dent Radiol. 2008; 47:111-112.  Back to cited text no. 13
    
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Jae-Seo Lee, Young-Hee Kim, Suk-Ja Yoon and Byung-Cheol Kang. reference dose levels for dental panoramic radiography in gwangju, south korea. Radiation Protection Dosimetry, 2010; 142(2-4): 184-190.  Back to cited text no. 14
    
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Eun-Kyung Kim, Won-Jeong Han, Jin-Woo Choi, Yun-Hoa Jung, Suk-Ja Yoon, Jae-Seo Lee. Diagnostic reference levels in intraoral dental radiography in Korea. Imaging Science in Dentistry. 2012; 42:237-242.  Back to cited text no. 15
    
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Christofides S, Pitri E, Lampaskis M, Papaefstathiou C. Local diagnostic reference levels for intraoral dental radiography in the public hospitals of Cyprus. Physica Med. 2016;32(11): 1437-1443.  Back to cited text no. 16
    
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Manousaridis G, Koukorava C, Hourdakis CJ, Kamenopoulou V, Yakoumakis E, Tsiklakis K. Establishment of diagnostic reference levels for dental intraoral radiography. Radiat Prot Dosim. 2013;156(4):455-457.  Back to cited text no. 17
    
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II. Sulimana, Aziza H. Abdelgadira. Patient radiation doses in intraoral and panoramic X-ray examinations in Sudan. Physica Medica. 2018;46:148-152.  Back to cited text no. 18
    
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Hodolli G, Kadiri S, Nafezi G, Bahtijari M, Syla N. Diagnostic reference levels at intraoral and dental panoramic examinations. International Journal of Radiation Research. 2019;17(1).  Back to cited text no. 19
    
20.
National Diagnostic Reference Levels Established in 2015 (Japan DRLs 2015) for Dental Intraoral Radiography. Available at: http://www.radher.jp/J-RIME/report/DRLhoukokusyoEng.pdf. Accessed 14 May 2020.  Back to cited text no. 20
    
21.
RSN – Institute for Radiological Protection and Nuclear Safety Dosimetric Evaluation in Dental Radiology. Radiological procedures performed for panoramic and volume acquisitions with the Kodak 9000 3D device. France, Report n°2008-07.  Back to cited text no. 21
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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