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Villamizar-Martinez LA, Losey J. Assessment of the Occupational Radiation Dose from a Handheld Portable X-ray Unit During Full-mouth Intraoral Dental Radiographs in the Dog and the Cat - A Pilot Study. J Vet Dent 2024; 41:106-113. [PMID: 37221884 DOI: 10.1177/08987564231175596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Occupational radiation protection is an important consideration in small animal clinics world-wide. With the increased use of portable handheld X-ray devices in veterinary dentistry, concerns related to occupational radiation protection are being raised. Annual occupational dose limits for dental workers are expressed as Total Dose Equivalent (TDE) or Effective Dose. The permitted TDE can vary depending on the anatomical region, ranging from 50 millisieverts (mSv) for the external whole body exposure dose to 500 mSv for external exposure of the skin or an extremity. Although several studies have been performed in human dentistry to establish the amount of backscatter radiation produced using portable handheld X-ray devices, no similar research has been conducted in veterinary dentistry. This study aimed to determine the TDE while acquiring a full mouth intraoral radiograph set in dogs and cats and to estimate the TDE for a handheld X-ray device's operator. For this, the backscatter radiation dose recorded by three sets of monitoring dosimeters located in strategic anatomical areas of the operator was assessed after taking one hundred intraoral radiographs in each group. The study concluded that the backscatter radiation levels were far below the permitted annual occupational doses in the three patient groups of this study. Even though the portable handheld X-ray unit was demonstrated to be a safe dental radiographic unit regarding backscattering radiation, the operator's eye, ovary, and breast regions were exposed to unnecessary radiation.
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Affiliation(s)
- Lenin A Villamizar-Martinez
- Dentistry and Oral Surgery Service, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Jeannie Losey
- Dentistry and Oral Surgery Service, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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Clark-Perry D, Berkhout WER, Sanderink GC, Slot DE. Evaluating cone cut in rectangular collimation in intraoral radiography: application of ALADA and radiation stewardship. Clin Oral Investig 2023; 27:5391-5402. [PMID: 37537518 PMCID: PMC10492766 DOI: 10.1007/s00784-023-05158-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 07/11/2023] [Indexed: 08/05/2023]
Abstract
OBJECTIVE Rectangular collimation is a popular method used in intraoral radiography to reduce patient exposure to ionizing radiation. One of the perceived drawbacks of rectangular collimation is the possibility of an increase in cone cut errors ultimately impacting the diagnostic value of the radiographs. Thus, the aim of this study was to explore the frequency of cone cut errors in radiographs taken using a rectangular collimator. MATERIALS AND METHODS Radiographs taken using PSP plates at Academic Center for Dentistry Amsterdam in the Netherlands by staff and students from January to December 2015 were assessed for cone cut errors. The radiographs were grouped as bitewings, front teeth, inferior premolars and molars, and superior premolars and molars and categorized as no cone cut, cone cut but diagnostically usable, and cone cut but diagnostically not usable. The results were entered into Microsoft Excel and analyzed thereafter. RESULTS A total of 53,684 radiographs were assessed, 79% had no cone cut errors and consequently 21% had some degree of cone cut. However, the diagnostic value was unaffected in 18% of the radiographs with cone cut. Only 3% of the radiographs were deemed diagnostically unusable due to cone cut. The most common area of cone cut was in the premolar and molar areas while cone cut in the front teeth was least likely to be diagnostically unusable. CONCLUSION Cone cut from the use of a rectangular collimator does not seem to result in an increase of diagnostically unusable radiographs. Thus, rectangular collimation should be preferred as it decreases the amount of radiation exposure to the patient while producing diagnostically usable radiographs and thus allowing the dental professional to adhere to the ALADA principle and practice radiation stewardship. CLINICAL RELEVANCE Scientific rationale for the study: rectangular collimation is a method used to reduce patient exposure to ionizing radiation; however, this benefit is negligible if radiographs must be retaken due to cone cut errors that make the radiograph diagnostically unusable. Therefore, the aim of this study was to explore the frequency of cone cut in radiographs taken using a rectangular collimator. PRINCIPAL FINDINGS cone cut was observed in 21% of the radiographs; however, only 3% of the radiographs were considered diagnostically unusable. PRACTICAL IMPLICATIONS rectangular collimation does not result in a high number of diagnostically unusable radiographs and should be used to reduce patient exposure to ionizing radiation.
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Affiliation(s)
- D Clark-Perry
- Department of Periodontology, Academic Centre for Dentistry, Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - W E R Berkhout
- Department of Oral Radiology, Academic Centre for Dentistry, Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - G C Sanderink
- Department of Oral Radiology, Academic Centre for Dentistry, Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D E Slot
- Department of Periodontology, Academic Centre for Dentistry, Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
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Kuchi Bhotla H, Balasubramanian B, Rengasamy KRR, Arumugam VA, Alagamuthu KK, Chithravel V, Chaudhary A, Alanazi AM, Pappuswamy M, Meyyazhagan A. Genotoxic repercussion of high-intensity radiation (x-rays) on hospital radiographers. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:123-131. [PMID: 36541415 DOI: 10.1002/em.22523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 05/24/2023]
Abstract
Recent technological advances in the medical field have increased the plausibility of exposing humans to high-intensity wavelength radiations like x-rays and gamma rays while diagnosing or treating specific medical maladies. These radiations induce nucleotide changes and chromosomal alterations in the exposed population, intentionally or accidentally. A radiological investigation is regularly used in identifying the disease, especially by the technicians working in intensive care units. The current study observes the genetic damages like chromosomal abnormalities (CA) in clinicians who are occupationally exposed to high-intensity radiations (x-rays) at their workplaces using universal cytogenetic tools like micronucleus assay (MN), sister chromatid exchange and comet assay. The study was conducted between 100 exposed practitioners from the abdominal scanning, chest scanning, cranial and orthopedic or bone scanning department and age-matched healthy controls. We observed a slightly higher rate of MN and CA (p < .05) in orthopedic and chest department practitioners than in other departments concerning increasing age and duration of exposure at work. Our results emphasize taking extra precautionary measures in clinical and hospital radiation laboratories to protect the practitioners.
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Affiliation(s)
| | | | - Kannan R R Rengasamy
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
- Laboratory of Natural Products and Medicinal Chemistry (LNPMC), Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, India
| | - Vijaya Anand Arumugam
- Medical Genetics and Epigenetics Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - Karthick Kumar Alagamuthu
- Department of Biotechnology, Selvamm Arts and Science College (Autonomous), Namakkal, Tamil Nadu, India
| | | | - Aditi Chaudhary
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore, India
| | - Amer M Alanazi
- Pharmaceutical Chemistry Department, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | | | - Arun Meyyazhagan
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore, India
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Basheer BT, Allahim RI, Alarfaj SS, Alkharashi TA, Fallatah AA, Alqahtani AS, Aljarallah SS. Evaluation of Radiation Exposure in Open Dental Clinics Using Thermoluminescence Dosimeters and Questionnaires. Contemp Clin Dent 2021; 12:266-275. [PMID: 34759684 PMCID: PMC8525804 DOI: 10.4103/ccd.ccd_598_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/23/2020] [Accepted: 09/07/2020] [Indexed: 11/24/2022] Open
Abstract
Aim: The aim of this study was to evaluate radiation exposure in dental open clinics in King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS) using thermoluminescence dosimeters (TLDs) to check if it exceeds the annual assigned exposure limit and to assess students' practices regarding radiation protection measures and their knowledge regarding the application of digital remote-control settings and TLDs. Materials and Methods: This pilot institutional-based observational study was conducted among the clinical year students and interns at KSAU-HS College of Dentistry open clinical areas using TLDs and questionnaires. Sixteen lithium fluoride TLDs (TLD-100) were distributed evenly in the clinical areas occupied by clinical year dental students and interns for 24 working days from September 15 to October 20, 2019. Each TLD was labeled with a serial number and fixed at the assigned clinic of each specialty. The TLDs were placed in a zigzag manner at the right corner of the selected clinic to prevent overlapping of the area coverage by each dosimeter. Results: The mean monthly TLD readings were found to be 69.265 uSv with a higher mean value in the female clinical area (74.2975 uSv) than the male clinical area (64.234 uSv). Taking into account the 8 months of clinical exposure during the academic year, the expected annual radiation exposure would be 0.554 mSv which is significantly lower than the annual limit of radiation exposure recommended by the International Commission on Radiological Protection, i.e., 1 mSv. Conclusion: TLD readings concluded that radiation exposure was within safe limits with an estimation of 0.544 mSv per year. However, students require further education regarding protective and safety measures and the utilization of radiation equipment. Clinical Significance: The lack of studies regarding the amount of radiation exposure from dental imaging and the safety of intraoral radiographic machines present in open clinics in any educational institute necessitates conducting this kind of study.
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Affiliation(s)
- Bahija T Basheer
- Department of Preventive Dental Sciences, College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA.,King Abdullah International Medical Research Center, Riyadh, KSA
| | - Renad I Allahim
- College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA
| | - Samar S Alarfaj
- College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA
| | - Tala A Alkharashi
- College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA
| | - Amal A Fallatah
- College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA
| | - Amerah S Alqahtani
- College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA
| | - Shuruq S Aljarallah
- College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, KSA
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Carlberg M, Koppel T, Hedendahl LK, Hardell L. Is the Increasing Incidence of Thyroid Cancer in the Nordic Countries Caused by Use of Mobile Phones? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E9129. [PMID: 33297463 PMCID: PMC7730276 DOI: 10.3390/ijerph17239129] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/26/2022]
Abstract
The International Agency for Research on Cancer (IARC) at the World Health Organization (WHO) categorized in 2011 radiofrequency (RF) as a possible human carcinogen, Group 2B. During use of the handheld wireless phone, especially the smartphone, the thyroid gland is a target organ. During the 21st century, the incidence of thyroid cancer is increasing in many countries. We used the Swedish Cancer Register to study trends from 1970 to 2017. During that time period, the incidence increased statistically significantly in women with average annual percentage change (AAPC) +2.13%, 95% confidence interval (CI) +1.43, +2.83%. The increase was especially pronounced during 2010-2017 with annual percentage change (APC) +9.65%, 95% CI +6.68, +12.71%. In men, AAPC increased during 1970-2017 with +1.49%, 95% CI +0.71, +2.28%. Highest increase was found for the time period 2001-2017 with APC +5.26%, 95% CI +4.05, +6.49%. Similar results were found for all Nordic countries based on NORDCAN 1970-2016 with APC +5.83%, 95% CI +4.56, +7.12 in women from 2006 to 2016 and APC + 5.48%, 95% CI +3.92, +7.06% in men from 2005 to 2016. According to the Swedish Cancer Register, the increasing incidence was similar for tumors ≤4 cm as for tumors >4 cm, indicating that the increase cannot be explained by overdiagnosis. These results are in agreement with recent results on increased thyroid cancer risk associated with the use of mobile phones. We postulate that RF radiation is a causative factor for the increasing thyroid cancer incidence.
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Affiliation(s)
- Michael Carlberg
- The Environment and Cancer Research Foundation, Studievägen 35, SE 702 17 Örebro, Sweden; (L.K.H.); (L.H.)
| | - Tarmo Koppel
- School of Business and Governance, Tallinn University of Technology, SOC353 Ehitajate Tee 5, 19086 Tallinn, Estonia;
| | - Lena K. Hedendahl
- The Environment and Cancer Research Foundation, Studievägen 35, SE 702 17 Örebro, Sweden; (L.K.H.); (L.H.)
| | - Lennart Hardell
- The Environment and Cancer Research Foundation, Studievägen 35, SE 702 17 Örebro, Sweden; (L.K.H.); (L.H.)
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A H P, S M R A, T B, M G, M M. Dosimetry of Occupational Radiation around Panoramic X-ray Apparatus. J Biomed Phys Eng 2019; 9:525-532. [PMID: 31750266 PMCID: PMC6820020 DOI: 10.31661/jbpe.v0i0.466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/20/2015] [Indexed: 11/16/2022]
Abstract
Background: Panoramic imaging is one of the most common imaging methods in dentistry. Regarding the side-effects of ionizing radiation, it is necessary to survey different aspects and details of panoramic imaging. In this study, we compared the absorbed x-ray dose around two panoramic x-ray units: PM 2002 CC Proline (Planmeca, Helsinki, Finland) and Cranex Tome (Soredex, Helsinki, Finland).
Materials and Methods: In this cross-sectional study, 15 thermoluminescet dosemeters (TLD-100) were placed in 3 semi-circles of 40cm, 80cm and 120cm radii in order to estimate x-ray dose. Around each unit, the number of TLDs in each semi-circle was 5 with equal intervals. The center of semicircles accords with the patient’s position. Each TLD was exposed 40 times. These dosemeters were read out with a Harshaw Model 4000 TLD Reader (USA). The calibration processing and the reading of dosemeters were performed by the Atomic Energy Organization of Iran.
Results: The mean absorbed dose in three lines of PM 2002 CC Proline was 123.2±15.1, 118.0±11.0 and 108.0±9.1 µSv, (p=0.013). The results were 140.4±15.2, 120.2±10.4 and 111.6±11.2 µSv in Cranex Tome (p=0.208), which reveals no significant difference between two systems.
Conclusion: There are no significant differences between the mean absorbed dose of surveyed models in panoramic imaging by two units (PM 2002 CC Proline and Cranex Tome). These results were less than occupational exposure recommended by ICRP, even at the highest calculated doses.
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Affiliation(s)
- Pakravan A H
- MD, Department of Prosthodontics, Faculty of Dentistry, Mazandaran University of Medical Sciences, Mazandaran, Iran
| | - Aghamiri S M R
- PhD, Department of Radiation Medicine, Shahid Beheshti University, Tehran, Iran
| | - Bamdadian T
- MD, Department of Prosthesis, Faculty of Dentistry, Mazandaran University of Medical Sciences, Mazandaran, Iran
| | - Gholami M
- PhD, Obesity and Eating Habits Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
- PhD, Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Moshfeghi M
- MD, Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Memon A, Rogers I, Paudyal P, Sundin J. Dental X-Rays and the Risk of Thyroid Cancer and Meningioma: A Systematic Review and Meta-Analysis of Current Epidemiological Evidence. Thyroid 2019; 29:1572-1593. [PMID: 31502516 DOI: 10.1089/thy.2019.0105] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background: Exposure to moderate-to-high doses of ionizing radiation is the only established environmental risk factor for thyroid cancer and brain and central nervous system tumors. Considering the high lifetime prevalence and frequency of exposure to dental X-rays, the most common source of diagnostic radiation exposure in the general population, even a small associated increase in cancer risk would be of considerable public health importance. With the objective to inform clinical practice and guidelines, we synthesized the current epidemiological evidence on the association between dental X-rays and the risk of thyroid cancer, meningioma, and other cancers of the head and neck region. Methods: The Medline, Embase, and Web of Science databases were searched to identify eligible studies. Summary odds ratio/relative risk estimates and confidence intervals were extracted, and pooled risk ratios (RRs) for each cancer were calculated using random effects meta-analysis. Results: The literature search identified 5537 publications; of these, 26 studies including 10,868 cancer patients were included in the synthesis. The random effects meta-analyses, based on seven studies of thyroid cancer (six case/control, one cohort) and eight studies of meningioma (all case/control), showed that multiple (or repeated) exposures to dental X-rays were significantly associated with an increased risk of thyroid cancer (pooled RR = 1.87 [95% confidence interval, CI 1.11-3.15]) and meningioma (pooled RR = 1.53 [CI 1.26-1.85]). There was no association with glioma, and there were too few studies of other cancers of the head and neck region to conduct a meaningful meta-analysis. Conclusions: Based on a meta-analysis of retrospective case/control studies, these findings provide some support to the hypothesis that multiple (or repeated) exposures to dental X-rays may be associated with an increased risk of thyroid cancer and meningioma. These studies did not include individual organ doses and ages at exposure, and are subject to recall bias and other limitations. Furthermore, the thyroid exposure has decreased dramatically over time from the use of thyroid shields and improved technology/equipment. Prospective studies, based on dental X-ray records and patient follow-up, are needed to test the hypothesis further and clarify the possible cancer risk associated with dental radiography, as although the risk at the individual level, particularly with improved technology/equipment, is likely to be very low, the proportion of the population exposed is high. Considering that about one-third of the general population in developed countries is routinely exposed to one or more dental X-rays per year, these findings manifest the need to reduce diagnostic radiation exposure as much as possible.
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Affiliation(s)
- Anjum Memon
- Department of Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, United Kingdom
| | - Imogen Rogers
- Department of Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, United Kingdom
| | - Priyamvada Paudyal
- Department of Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, United Kingdom
| | - Josefin Sundin
- Department of Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, United Kingdom
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Wong YS, Cheng YY, Cheng TJ, Huang CC, Yeh JJ, Guo HR. The Relationship Between Occupational Exposure to Low-dose Ionizing Radiation and Changes in Thyroid Hormones in Hospital Workers. Epidemiology 2019. [DOI: org/10.1097/ede.0000000000001004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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The Relationship Between Occupational Exposure to Low-dose Ionizing Radiation and Changes in Thyroid Hormones in Hospital Workers. Epidemiology 2019; 30 Suppl 1:S32-S38. [PMID: 31181004 DOI: 10.1097/ede.0000000000001004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND The effects of ionized radiation on the thyroid have been extensively studied. However, most studies have focused on high-dose radiation received accidentally or through therapy, and few were on low-dose occupational exposure. METHODS Using a retrospective cohort study design, we collected health examination reports from employees who worked on jobs with occupational exposure to radiation at a hospital to evaluate possible changes in the serum thyroid hormones and determine whether there is a dose-response effect. After excluding those with diseases that may affect thyroid function and who were pregnant at any given examination during the study periods we followed the remaining 326 workers for 12 years and evaluated the associations between radiation exposure and changes in serum thyroid hormones using the generalized estimating equation for repeated measures. Data from an external comparison cohort were used to adjust for changes over time. RESULTS We observed declines in triiodothyronine (T3) and thyroxine (T4) over the study period, but not in thyroid-stimulating hormone (TSH). In addition, we found negative dose-response relationships between exposure duration and declines in the serum levels of T3 (a change of -0.037 ng/ml/year after adjusting for sex and age at the beginning of follow-up; 95% confidence interval [CI] = -0.042, -0.032 ng/ml/year) and T4 (-0.115 µg/dl/year; 95% CI = -0.140, -0.091 µg/dl/year). We also observed an increase in the TSH level (0.683 µIU/ml/year; 95% CI = 0.151, 1.214 µIU/ml/year) after the ninth year of follow-up. CONCLUSIONS We concluded that despite low exposure doses, occupational exposure to ionizing radiation in healthcare workers still may be associated with the declines in the serum levels of T3 and T4.
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Chauhan V, Wilkins RC. A comprehensive review of the literature on the biological effects from dental X-ray exposures. Int J Radiat Biol 2019; 95:107-119. [PMID: 30496029 DOI: 10.1080/09553002.2019.1547436] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE Routine dental X-rays are among the most common sources of ionizing radiation exposure for healthy individuals globally, with 300 examinations/1000 individuals/year as documented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) global survey of medical radiation usage and exposure. Furthermore, in the United States of America, an increased use of dental radiography is evident. However, with the shift from using film to digital image receptors, the dose of radiation per routine examination has decreased. Despite this, there remains public concern of dental X-rays. This continuing concern highlights the need to review the literature on biological and health effects related to exposure, from dental X-rays. MATERIAL AND METHODS This report presents studies investigating biological and health effects related to exposures using dental X-rays in patients and provides a critical evaluation. Relevant studies specific to dental X-rays are reviewed from 1970 and onward with the bulk data in this field resulting from epidemiological and biomonitoring studies. RESULTS While, most epidemiological studies suggest a possible correlation between head/neck related tumors and exposure to dental X-rays, evidence for causation is lacking. Biomonitoring studies suggest that exposure to low-level radiation such as that of dental radiography may not be a factor in inducing long-term chromosomal damage, but may result in localized cytotoxicity in the irradiated region of the mouth, with no long-term harm. CONCLUSIONS In general, the total number of studies is low and the majority of the data has been generated from poorly designed experiments. This review will highlight shortcomings that could influence outcomes and provide a more balanced interpretation that could impact the public perception and the level of public concern on the health effects resulting from dental X-rays.
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Affiliation(s)
- Vinita Chauhan
- a Consumer and Clinical Radiation Protection Bureau, Healthy Environments and Consumer Safety Branch , Health Canada , Ottawa , Canada
| | - Ruth C Wilkins
- a Consumer and Clinical Radiation Protection Bureau, Healthy Environments and Consumer Safety Branch , Health Canada , Ottawa , Canada
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11
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Hwang SY, Choi ES, Kim YS, Gim BE, Ha M, Kim HY. Health effects from exposure to dental diagnostic X-ray. ENVIRONMENTAL HEALTH AND TOXICOLOGY 2018; 33:e2018017. [PMID: 30661338 PMCID: PMC6341170 DOI: 10.5620/eht.e2018017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/04/2018] [Indexed: 05/05/2023]
Abstract
The purpose of this review is to summarize the results of studies on of the association between exposure to dental X-rays and health risk. To perform the systematic review, We searched the PUBMED, EMBASE, and MEDLINE databases for papers published before December 15, 2016. A total of 2 158 studies, excluding duplicate studies, were found. Two reviewers independently evaluated the eligibility of each study. The final 21 studies were selected after application of exclusion criteria. In terms of health outcomes, there were 10 studies about brain tumors, 5 about thyroid cancer, 3 about tumors of head and neck areas, and 3 related to systemic health. In brain tumor studies, the association between dental X-ray exposure and meningioma was statistically significant in 5 of the 7 studies. In 4 of the 5 thyroid-related studies, there was a significant correlation with dental diagnostic X-rays. In studies on head and neck areas, tumors included laryngeal, parotid gland, and salivary gland cancers. There was also a statistically significant correlation between full-mouth X-rays and salivary gland cancer, but not parotid gland cancer. Health outcomes such as leukemia, low birth weight, cataracts, and thumb carcinomas were also reported. In a few studies examining health effects related to dental X-ray exposure, possibly increased risks of meningioma and thyroid cancer were suggested. More studies with a large population and prospective design are needed to elaborate these associations further.
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Affiliation(s)
- Su-Yeon Hwang
- Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea
| | - Eun-Sil Choi
- Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea
| | - Young-Sun Kim
- Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea
| | - Bo-Eun Gim
- Expert Group on Health Promotion for Seoul Metropolitan Government, Seoul, Korea
| | - Mina Ha
- Department of Preventive Medicine, Dankook University College of Medicine, Cheonan, Korea
| | - Hae-Young Kim
- Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea
- Department of Health Policy and Management, College of Health Science, Korea University, Seoul, Korea
- Corresponding author: Hae-Young Kim Department of Health Policy and Management, College of Health Sciences, Korea University, 73 Inchon-ro, Seongbuk-gu, Seoul 02841, Korea E-mail:
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12
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Drozd VM, Branovan I, Shiglik N, Biko J, Reiners C. Thyroid Cancer Induction: Nitrates as Independent Risk Factors or Risk Modulators after Radiation Exposure, with a Focus on the Chernobyl Accident. Eur Thyroid J 2018; 7:67-74. [PMID: 29594057 PMCID: PMC5869559 DOI: 10.1159/000485971] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 12/01/2017] [Indexed: 12/31/2022] Open
Abstract
In recent decades, differentiated thyroid cancer (DTC) incidence has been increasing worldwide. The important contributions to this phenomenon of "overdiagnosis" driven by wider use of improved ultrasound systems are amply documented, notwithstanding the "real" carcinogenic effects of ionizing radiation, e.g., from the Chernobyl accident or health care interventions. Less well understood is the role of nitrates - as environmental pollutants, in diet, and in medication - in thyroid carcinogenesis. Increasing exposure to nitrates is associated with rising incidence of esophageal, stomach, bladder, and colon cancers. Recent data suggest that in agricultural areas with higher mean nitrate levels in groundwater, DTC risk is also elevated. Our work in Belarus after Chernobyl has shown that children in districts with high nitrate concentrations in drinking water had significantly higher thyroid cancer incidence after irradiation than did their counterparts in areas with lower nitrate concentrations. Notwithstanding thyroid shielding, increasing use of computed tomography and dental X-rays heightens radiation exposure of the salivary glands in the general population, especially in children and adolescents. When nitrate intake is increased, salivary gland irradiation may potentially result in carcinogenic elevations in plasma nitric oxide concentrations. In conclusion, excess nitrate intake seems to be an independent risk factor for DTC. Additionally, we hypothesize from our data that high nitrate levels modulate the carcinogenic effect of radiation on the thyroid. Cohort studies, case-control studies, or both, are needed to quantify the effects of nitrates on DTC risk in the presence or absence of radiation exposure, e.g., that associated with diagnostic or therapeutic health care interventions.
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Affiliation(s)
- Valentina M. Drozd
- The International Fund “Help for patients with radiation-induced thyroid cancer ‘Arnica’”, Minsk, Belarus
- Project Chernobyl, Brooklyn, New York, USA
- *Prof. Valentina M. Drozd, MD, PhD, The International Fund “Help for patients with radiation-induced thyroid cancer ‘Arnica’”, Zolotaya Gorka 11, 1, Minsk 220005 (Belarus), E-Mail
| | | | | | - Johannes Biko
- Clinic and Polyclinic of Nuclear Medicine, University of Würzburg, Würzburg, Germany
| | - Christoph Reiners
- The International Fund “Help for patients with radiation-induced thyroid cancer ‘Arnica’”, Minsk, Belarus
- Clinic and Polyclinic of Nuclear Medicine, University of Würzburg, Würzburg, Germany
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13
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Crane GD, Abbott PV. Radiation shielding in dentistry: an update. Aust Dent J 2017; 61:277-81. [PMID: 26644147 DOI: 10.1111/adj.12389] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2015] [Indexed: 11/26/2022]
Abstract
The purpose of this article was to review the literature and provide guidelines on the use of radiation protection for patients in the dental setting. There are limited published data on the effects of low radiation doses such as those used in dental radiology. Most of the evidence is subject to bias, with risk models extrapolated from higher dose models such as studies of the Hiroshima bomb survivors. However, the lack of evidence does not denote the absence of risk, as there is no established 'safe' level of radiation exposure. All imaging utilizing ionizing radiation carries a risk for the patient. Hence the patient benefits of imaging must outweigh the potential risk. All diagnostic imaging should adhere to three basic principles, these being justification, optimization and application of dose limits. This article discusses dose reduction techniques and shielding of sensitive organs, particularly the thyroid, during procedures such as intraoral imaging, orthopantomograms and imaging of the pregnant patient.
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Affiliation(s)
- G D Crane
- School of Dentistry, Oral Health Centre of Western Australia, The University of Western Australia, Australia
| | - P V Abbott
- School of Dentistry, Oral Health Centre of Western Australia, The University of Western Australia, Australia
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14
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Carlberg M, Hedendahl L, Ahonen M, Koppel T, Hardell L. Increasing incidence of thyroid cancer in the Nordic countries with main focus on Swedish data. BMC Cancer 2016; 16:426. [PMID: 27388603 PMCID: PMC4937579 DOI: 10.1186/s12885-016-2429-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Radiofrequency radiation in the frequency range 30 kHz-300 GHz was evaluated to be Group 2B, i.e. 'possibly' carcinogenic to humans, by the International Agency for Research on Cancer (IARC) at WHO in May 2011. Among the evaluated devices were mobile and cordless phones, since they emit radiofrequency electromagnetic fields (RF-EMF). In addition to the brain, another organ, the thyroid gland, also receives high exposure. The incidence of thyroid cancer is increasing in many countries, especially the papillary type that is the most radiosensitive type. METHODS We used the Swedish Cancer Register to study the incidence of thyroid cancer during 1970-2013 using joinpoint regression analysis. RESULTS In women, the incidence increased statistically significantly during the whole study period; average annual percentage change (AAPC) +1.19 % (95 % confidence interval (CI) +0.56, +1.83 %). Two joinpoints were detected, 1979 and 2001, with a high increase of the incidence during the last period 2001-2013 with an annual percentage change (APC) of +5.34 % (95 % CI +3.93, +6.77 %). AAPC for all men during 1970-2013 was +0.77 % (95 % CI -0.03, +1.58 %). One joinpoint was detected in 2005 with a statistically significant increase in incidence during 2005-2013; APC +7.56 % (95 % CI +3.34, +11.96 %). Based on NORDCAN data, there was a statistically significant increase in the incidence of thyroid cancer in the Nordic countries during the same time period. In both women and men a joinpoint was detected in 2006. The incidence increased during 2006-2013 in women; APC +6.16 % (95 % CI +3.94, +8.42 %) and in men; APC +6.84 % (95 % CI +3.69, +10.08 %), thus showing similar results as the Swedish Cancer Register. Analyses based on data from the Cancer Register showed that the increasing trend in Sweden was mainly caused by thyroid cancer of the papillary type. CONCLUSIONS We postulate that the whole increase cannot be attributed to better diagnostic procedures. Increasing exposure to ionizing radiation, e.g. medical computed tomography (CT) scans, and to RF-EMF (non-ionizing radiation) should be further studied. The design of our study does not permit conclusions regarding causality.
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Affiliation(s)
- Michael Carlberg
- />Department of Oncology, Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
| | - Lena Hedendahl
- />Independent Environment and Health Research Luleå, Östra Skolgatan 12, SE-972 53 Luleå, Sweden
| | - Mikko Ahonen
- />Institute of Environmental Health and Safety, Jaama 14-3, 11615 Tallinn, Estonia
| | - Tarmo Koppel
- />Department of Labour Environment and Safety, Tallinn University of Technology, SCO351 Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Lennart Hardell
- />Department of Oncology, Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
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15
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Diagnostic radiography exposure increases the risk for thyroid microcarcinoma: a population-based case-control study. Eur J Cancer Prev 2016; 24:439-46. [PMID: 25932870 DOI: 10.1097/cej.0000000000000169] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Thyroid cancer incidence and diagnostic radiography exposures, particularly computed tomography (CT) scanning and nuclear medicine examinations, have increased substantially in the USA. However, very few epidemiologic studies have directly investigated their associations. A population-based case-control study was conducted in Connecticut in 2010-2011, including 462 histologically confirmed incident thyroid cancer cases and 498 population-based controls. Multivariate unconditional logistic regression models were used to estimate the associations between diagnostic radiography and the risk of thyroid cancer, controlling for potential confounding factors. Exposure to any form of diagnostic radiography was associated with an increased risk of well-differentiated thyroid microcarcinoma [tumor size≤10 mm, odds ratio (OR)=2.76, 95% confidence interval (CI): 1.31-5.81]. The highest risk increase occurred with nuclear medicine examinations (excluding cardiology tests and thyroid uptake studies; OR=5.47, 95% CI: 2.10-14.23), followed by chest CT scanning (OR=4.30, 95% CI: 1.66-11.14), head and neck CT scanning (OR=3.88, 95% CI: 1.75-8.63), upper gastrointestinal series (OR=3.56, 95% CI: 1.54-8.21), lower gastrointestinal series (OR=3.29, 95% CI: 1.41-7.66), kidney radiography involving dye injection into a vein or artery (OR=3.21, 95% CI: 1.20-8.54), mammography (OR=2.95, 95% CI: 1.14-7.61), chest radiography (OR=2.93, 95% CI: 1.37-6.29), and abdomen CT scanning (OR=2.54, 95% CI: 1.02-6.30). No significant associations were found between these imaging modalities and thyroid tumors larger than 10 mm. This study provides the first direct evidence that CT scanning and nuclear medicine examinations are associated with an increased risk of thyroid cancer. The novel finding that an array of diagnostic radiography procedures are associated with thyroid microcarcinomas warrants further investigation.
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16
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Svenson B, Larsson L, Båth M. Optimization of exposure in panoramic radiography while maintaining image quality using adaptive filtering. Acta Odontol Scand 2015; 74:229-35. [PMID: 26478956 DOI: 10.3109/00016357.2015.1100752] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Objective The purpose of the present study was to investigate the potential of using advanced external adaptive image processing for maintaining image quality while reducing exposure in dental panoramic storage phosphor plate (SPP) radiography. Materials and methods Thirty-seven SPP radiographs of a skull phantom were acquired using a Scanora panoramic X-ray machine with various tube load, tube voltage, SPP sensitivity and filtration settings. The radiographs were processed using General Operator Processor (GOP) technology. Fifteen dentists, all within the dental radiology field, compared the structural image quality of each radiograph with a reference image on a 5-point rating scale in a visual grading characteristics (VGC) study. The reference image was acquired with the acquisition parameters commonly used in daily operation (70 kVp, 150 mAs and sensitivity class 200) and processed using the standard process parameters supplied by the modality vendor. Results All GOP-processed images with similar (or higher) dose as the reference image resulted in higher image quality than the reference. All GOP-processed images with similar image quality as the reference image were acquired at a lower dose than the reference. This indicates that the external image processing improved the image quality compared with the standard processing. Regarding acquisition parameters, no strong dependency of the image quality on the radiation quality was seen and the image quality was mainly affected by the dose. Conclusions The present study indicates that advanced external adaptive image processing may be beneficial in panoramic radiography for increasing the image quality of SPP radiographs or for reducing the exposure while maintaining image quality.
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MESH Headings
- Filtration/instrumentation
- Humans
- Image Processing, Computer-Assisted/methods
- Image Processing, Computer-Assisted/standards
- Phantoms, Imaging
- Radiation Dosage
- Radiographic Image Enhancement/methods
- Radiography, Dental, Digital/methods
- Radiography, Dental, Digital/standards
- Radiography, Panoramic/methods
- Radiography, Panoramic/standards
- Skull/diagnostic imaging
- Technology, Radiologic/methods
- X-Ray Intensifying Screens
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Affiliation(s)
- Björn Svenson
- a Department of Oral Radiology , Postgraduate Dental Education Center , Örebro , Sweden
- b Faculty of Medicine and Health , School of Health and Medical Sciences, Örebro University , Örebro , Sweden
- c Department of Radiology , Skaraborg Hospital Skövde , Skövde , Sweden
| | - Lars Larsson
- c Department of Radiology , Skaraborg Hospital Skövde , Skövde , Sweden
| | - Magnus Båth
- d Department of Medical Physics and Biomedical Engineering , Sahlgrenska University Hospital , Gothenburg , Sweden
- e Department of Radiation Physics , Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden
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17
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Koifman S, Malhão TA, Pinto de Oliveira G, de Magalhães Câmara V, Koifman RJ, Meyer A. Cancer mortality among Brazilian dentists. Am J Ind Med 2014; 57:1255-64. [PMID: 25164308 DOI: 10.1002/ajim.22369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2014] [Indexed: 11/09/2022]
Abstract
BACKGROUND Previous studies have variably shown excess risks of elected cancers among dentists. METHODS National Brazilian mortality data were used to obtain mortality patterns among dentists between 1996 and 2004. Cancer mortality odds ratios (MORs) and cancer proportional mortality ratios for all cancer sites were calculated, using the general population and physicians and lawyers as comparison groups. RESULTS Female dentists from both age strata showed higher risks for breast, colon-rectum, lung, brain, and non-Hodgkin lymphoma. Compared to physicians and lawyers, higher MOR estimates were observed for brain cancer among female dentists 20-49 yr. Among male dentists, higher cancer mortality was found for colon-rectum, pancreas, lung, melanoma, and non-Hodgkin lymphoma. Higher risk estimates for liver, prostate, bladder, brain, multiple myeloma and leukemia were observed among 50-79 yr old male dentists. DISCUSSION If confirmed, these results indicate the need for limiting occupational exposures among dentists in addition to establishing screening programs to achieve early detection of selected malignant tumors.
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Affiliation(s)
- Sergio Koifman
- Department of Epidemiology and Quantitative Methods; National School of Public Health; Oswaldo Cruz Foundation; Rio de Janeiro Brazil
| | - Thainá Alves Malhão
- Institute for Studies in Collective Health; Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | - Gisele Pinto de Oliveira
- Institute for Studies in Collective Health; Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | | | - Rosalina Jorge Koifman
- Department of Epidemiology and Quantitative Methods; National School of Public Health; Oswaldo Cruz Foundation; Rio de Janeiro Brazil
| | - Armando Meyer
- Institute for Studies in Collective Health; Federal University of Rio de Janeiro; Rio de Janeiro Brazil
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18
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Neta G, Rajaraman P, Berrington de Gonzalez A, Doody MM, Alexander BH, Preston D, Simon SL, Melo D, Miller J, Freedman DM, Linet MS, Sigurdson AJ. A prospective study of medical diagnostic radiography and risk of thyroid cancer. Am J Epidemiol 2013; 177:800-9. [PMID: 23529772 DOI: 10.1093/aje/kws315] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although diagnostic x-ray procedures provide important medical benefits, cancer risks associated with their exposure are also possible, but not well characterized. The US Radiologic Technologists Study (1983-2006) is a nationwide, prospective cohort study with extensive questionnaire data on history of personal diagnostic imaging procedures collected prior to cancer diagnosis. We used Cox proportional hazard regressions to estimate thyroid cancer risks related to the number and type of selected procedures. We assessed potential modifying effects of age and calendar year of the first x-ray procedure in each category of procedures. Incident thyroid cancers (n = 251) were diagnosed among 75,494 technologists (1.3 million person-years; mean follow-up = 17 years). Overall, there was no clear evidence of thyroid cancer risk associated with diagnostic x-rays except for dental x-rays. We observed a 13% increase in thyroid cancer risk for every 10 reported dental radiographs (hazard ratio = 1.13, 95% confidence interval: 1.01, 1.26), which was driven by dental x-rays first received before 1970, but we found no evidence that the relationship between dental x-rays and thyroid cancer was associated with childhood or adolescent exposures as would have been anticipated. The lack of association of thyroid cancer with x-ray procedures that expose the thyroid to higher radiation doses than do dental x-rays underscores the need to conduct a detailed radiation exposure assessment to enable quantitative evaluation of risk.
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Affiliation(s)
- Gila Neta
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD, USA.
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19
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Goren AD, Prins RD, Dauer LT, Quinn B, Al-Najjar A, Faber RD, Patchell G, Branets I, Colosi DC. Effect of leaded glasses and thyroid shielding on cone beam CT radiation dose in an adult female phantom. Dentomaxillofac Radiol 2013; 42:20120260. [PMID: 23412460 DOI: 10.1259/dmfr.20120260] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES This study aims to demonstrate the effectiveness of leaded glasses in reducing the lens of eye dose and of lead thyroid collars in reducing the dose to the thyroid gland of an adult female from dental cone beam CT (CBCT). The effect of collimation on the radiation dose in head organs is also examined. METHODS Dose measurements were conducted by placing optically stimulated luminescent dosemeters in an anthropomorphic female phantom. Eye lens dose was measured by placing a dosemeter on the anterior surface of the phantom eye location. All exposures were performed on one commercially available dental CBCT machine, using selected collimation and exposure techniques. Each scan technique was performed without any lead shielding and then repeated with lead shielding in place. To calculate the percent reduction from lead shielding, the dose measured with lead shielding was divided by the dose measured without lead shielding. The percent reduction from collimation was calculated by comparing the dose measured with collimation to the dose measured without collimation. RESULTS The dose to the internal eye for one of the scans without leaded glasses or thyroid shield was 0.450 cGy and with glasses and thyroid shield was 0.116 cGy (a 74% reduction). The reduction to the lens of the eye was from 0.396 cGy to 0.153 cGy (a 61% reduction). Without glasses or thyroid shield, the thyroid dose was 0.158 cGy; and when both glasses and shield were used, the thyroid dose was reduced to 0.091 cGy (a 42% reduction). CONCLUSIONS Collimation alone reduced the dose to the brain by up to 91%, with a similar reduction in other organs. Based on these data, leaded glasses, thyroid collars and collimation minimize the dose to organs outside the field of view.
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Affiliation(s)
- A D Goren
- Department of Cariology and Comprehensive Care, New York University College of Dentistry, New York, NY 10010, USA.
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20
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Jadu F, Yaffe MJ, Lam EWN. A comparative study of the effective radiation doses from cone beam computed tomography and plain radiography for sialography. Dentomaxillofac Radiol 2010; 39:257-63. [PMID: 20587648 DOI: 10.1259/dmfr/62878962] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES As a first step in developing a protocol for multidimensional sialography using cone beam CT (CBCT), the objective of this study was to compare the effective radiation doses from sialography of the parotid and submandibular glands using plain radiography and CBCT. METHODS The effective doses were calculated from dose measurements made at 25 selected locations in the head and neck of a radiation analogue dosimeter (RANDO) phantom, using International Commission on Radiological Protection 2007 tissue weighting factors. RESULTS The effective dose (E) changed in relationship to changes in CBCT field of view (FOV), peak kilovoltage (kVp) and milliamperage (mA). Specifically, E decreased from a maximum of 932 microSv (30 cm FOV, 120 kVp, 15 mA) to 60 microSv (15 cm FOV, 80 kVp, 10 mA) for a parotid gland study and to 148 microSv (15 cm FOV, 80 kVp, 10 mA) for a submandibular study. The collective series of plain radiographs made during sialography of the parotid and submandibular glands yielded effective doses of 65 microSv and 156 microSv, respectively. The plain parotid gland series included one panoramic, two anterior-posterior skull and four lateral skull radiographs, whereas the submandibular gland series included one panoramic, one standard mandibular occlusal and four lateral skull radiographs. CONCLUSION The effective doses from CBCT examinations centred on the parotid and submandibular glands were similar to those calculated for plain radiograph sialography when a 15 cm FOV was chosen in combination with exposure conditions of 80 kVp and 10 mA.
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Affiliation(s)
- F Jadu
- Discipline of Oral and Maxillofacial Radiology, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada
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21
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Memon A, Godward S, Williams D, Siddique I, Al-Saleh K. Dental x-rays and the risk of thyroid cancer: a case-control study. Acta Oncol 2010; 49:447-53. [PMID: 20397774 DOI: 10.3109/02841861003705778] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
UNLABELLED The thyroid gland is highly susceptible to radiation carcinogenesis and exposure to high-dose ionising radiation is the only established cause of thyroid cancer. Dental radiography, a common source of low-dose diagnostic radiation exposure in the general population, is often overlooked as a radiation hazard to the gland and may be associated with the risk of thyroid cancer. An increased risk of thyroid cancer has been reported in dentists, dental assistants, and x-ray workers; and exposure to dental x-rays has been associated with an increased risk of meningiomas and salivary tumours. METHODS To examine whether exposure to dental x-rays was associated with the risk of thyroid cancer, we conducted a population-based case-control interview study among 313 patients with thyroid cancer and a similar number of individually matched (year of birth +/- three years, gender, nationality, district of residence) control subjects in Kuwait. RESULTS Conditional logistic regression analysis, adjusted for other upper-body x-rays, showed that exposure to dental x-rays was significantly associated with an increased risk of thyroid cancer (odds ratio = 2.1, 95% confidence interval: 1.4, 3.1) (p=0.001) with a dose-response pattern (p for trend <0.0001). The association did not vary appreciably by age, gender, nationality, level of education, or parity. DISCUSSION These findings, based on self-report by cases/controls, provide some support to the hypothesis that exposure to dental x-rays, particularly multiple exposures, may be associated with an increased risk of thyroid cancer; and warrant further study in settings where historical dental x-ray records may be available.
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Affiliation(s)
- Anjum Memon
- Division of Primary Care and Public Health, Brighton and Sussex Medical School, Falmer, Sussex, UK.
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22
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Hujoel P, Hollender L, Bollen AM, Young JD, McGee M, Grosso A. Radiographs Associated with One Episode of Orthodontic Therapy. J Dent Educ 2006. [DOI: 10.1002/j.0022-0337.2006.70.10.tb04178.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Philippe Hujoel
- Department of Dental Public Health Sciences; School of Dentistry; University of Washington
| | | | - Anne-Marie Bollen
- Department of Orthodontics; School of Dentistry; University of Washington
| | | | - Molly McGee
- Department of Environmental Health and Safety; University of Washington
| | - Alex Grosso
- Department of Environmental Health and Safety; University of Washington
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Abstract
This prospective study was conducted to determine the level of radiation exposure of trainee anaesthetists working in urology, orthopaedics and radiology environments. Anaesthetists wore lithium fluoride thermoluminescent dosimeter (TLD) badges over a 6-month period. The position of badges was standardised at the collar site (TLD1) and at waist level (TLD2). Area specific dosimeters were used and exchanged between anaesthetists. Of a total of 723 procedures, anaesthetists were exposed to radiation in 33% of procedures in orthopaedics, 30% in urology and 39% in radiology. The mean (SD) exposure time to radiation per case was significantly greater in orthopaedics than in urology (9.2 (4) min vs. 4.2 (2) min). The radiation exposure per case was highest in radiology (19.2 (22) min). The net combined exposure over a 6-month period was 0.2177 mSv in urology, 0.4265 mSv in orthopaedics and 3.8457 mSv in radiology. The combined exposure was less than the 20 mSv recommended as the maximum exposure per year. Our data does not support the need for routine dosimetric monitoring of anaesthetists working in the above settings.
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Affiliation(s)
- S Ismail
- Department of Anaesthesia, Aga Khan University, Karachi, Pakistan
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24
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McLean D, Smart R, Collins L, Varas J. Thyroid dose measurements for staff involved in modified barium swallow exams. HEALTH PHYSICS 2006; 90:38-41. [PMID: 16340606 DOI: 10.1097/01.hp.0000174812.97049.0e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Following a successful claim for damages by a speech pathologist, who was diagnosed with thyroid cancer after a period of employment including involvement in modified barium swallow procedures, a detailed study on occupational dose was commissioned. In this study radiation doses were measured routinely over 8 clinical periods using TLD100H dosimeters for staff involved with modified barium swallow radiological studies at three hospitals. The regions monitored included the unshielded thyroid, waist under apron, and axilla. Average unshielded thyroid doses for the speech pathologists were measured as 0.017, 0.003, and nil mGy per procedure over the hospitals surveyed, with dose measurements also found for the unshielded thyroid of the radiologist and nurse. This compares to thyroid doses of 0.200 and 0.055 mGy per procedure typically for cardiologists and orthopedic surgeons involved in radiological work, respectively. The use of a thyroid collar will substantially reduce this dose by a factor of about 40. While the worst-case doses are very small, attention should be given to education for staff involved in radiological procedures as well as ensuring that sound procedure protocols are in place and used.
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Affiliation(s)
- Donald McLean
- Department of Medical Physics, Westmead Hospital, NSW 2145, Australia.
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25
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Lope V, Pollán M, Gustavsson P, Plato N, Pérez-Gómez B, Aragonés N, Suárez B, Carrasco JM, Rodríguez S, Ramis R, Boldo E, López-Abente G. Occupation and thyroid cancer risk in Sweden. J Occup Environ Med 2005; 47:948-57. [PMID: 16155480 DOI: 10.1097/01.jom.0000169564.21523.5d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The objective of this study was to identify occupations and industries with increased incidence of thyroid cancer in Swedish workers. METHOD Standardized incidence ratios were computed for each job and industry for the period 1971-1989 through record-linkage with the Swedish National Cancer and Death Registers. Age-, period-, geographically adjusted relative risks were calculated using Poisson models. RESULTS Increased risks were found for teachers, construction carpenters, policemen, and prison/reformatory officials in men, and medical technicians, shop managers, tailors, and shoecutters among women. Industries with risk excess are manufacture of agricultural machinery, manufacture of computing/accessories, and public administration/police among men; and manufacture of prefabricated wooden buildings, electric installation work, and wholesale of live animals/fertilizers/oilseed/grain among women. CONCLUSIONS Our results corroborate some previously reported increased risks. Further research is needed to assess the influence of specific chemical agents related with some of the highlighted work environments.
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Affiliation(s)
- Virginia Lope
- Cancer and Environmental Epidemiology Area, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain.
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26
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Robinson S, Suomalainen A, Kortesniemi M. μ-CT. Eur J Radiol 2005; 56:185-91. [PMID: 16233892 DOI: 10.1016/j.ejrad.2005.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Revised: 03/05/2005] [Accepted: 03/08/2005] [Indexed: 11/26/2022]
Abstract
While many radiologists are aware of the revolutionary development of computed tomography (CT)-scanners and their diagnostic implications, some researchers have focused on studying the potentials of mu-CT. The aim of this article is to give a brief overview of its physical properties and outline possible indications both for the real ex vivo and small animal mu-CT studies, as well as the modified mu-CT units used in dental practice.
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Affiliation(s)
- Soraya Robinson
- Helsinki University Central Hospital, Department of Radiology, Haartmaninkatu 4, POB 340, FIN-00029 HUS Helsinki, Finland.
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27
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Hujoel P, Hollender LG. More than 5 full-mouth radiographic series increases intracranial meningioma risk. J Evid Based Dent Pract 2005; 5:162-3. [PMID: 17138363 DOI: 10.1016/j.jebdp.2005.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Philippe Hujoel
- Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle, Washington, USA
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28
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Hallquist A, Jansson P. Self-reported diagnostic X-ray investigation and data from medical records in case–control studies on thyroid cancer: evidence of recall bias? Eur J Cancer Prev 2005; 14:271-6. [PMID: 15901997 DOI: 10.1097/00008469-200506000-00012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of the present investigation was to evaluate and compare data from medical records with mailed questionnaires concerning risk factors for diagnostic X-ray investigation induced thyroid cancer. This study encompassed 180 patients and 360 controls, selected from the National Population Registry. Information on medical X-ray exposure was obtained by medical records and also from mailed questionnaires, with a latency of 5 years from diagnosis. The mailed questionnaire was answered by 171 cases (95%) and 325 controls (90%). In 132 cases and 251 controls data on medical records were collected and compared with data from mailed questionnaires for the same subjects. No earlier X-ray investigation based upon medical records was reported in 39 cases and in 74 controls. The median cumulative thyroid dose for cases was 1.1 mGy in medical records and in mailed questionnaire 0.6 mGy. For the controls the respective median cumulative dose was 1.0 mGy in medical records and 0.3 mGy in mailed questionnaires. The median ratio between medical records and mailed questionnaires in the cases was 2.1. For the controls the median ratio was 2.9. Wilcoxon's Matched Pairs Test (WMPT) showed a significantly underreport of thyroid X-ray dose in both cases (P<0.01) and controls (P<0.000001). In cases younger than 50 years at the time of the diagnosis of thyroid cancer there was not a significant underreport of X-ray examinations. Corresponding data from the control group showed however a significant underreport. Both cases and controls older than 50 reported significantly fewer X-ray investigations compared with data from medical records. A significant underreport was found among women both in cases and controls. For men there was a slight underreport among both cases and controls, although not significant. In conclusion, when studying diagnostic X-ray investigation as a risk factor for thyroid cancer, it is important to reduce the potential for recall bias when the study relies only on case-control reporting. To complement a case-control study with prospective medical data recorded at the time of the investigation could be an appropriate way to reduce the risk for recall bias.
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Affiliation(s)
- A Hallquist
- Department of Oncology-Pathology, Karolinska Institute, Radiumhemmet, The Hospital of Danderyd, SE-182 88 Stockholm, Sweden.
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Gijbels F, Jacobs R, Debaveye D, Bogaerts R, Verlinden S, Sanderink G. Dosimetry of digital panoramic imaging. Part II: occupational exposure. Dentomaxillofac Radiol 2005; 34:150-3. [PMID: 15897285 DOI: 10.1259/dmfr/65011036] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To measure occupational radiation dose during panoramic exposure from five digital panoramic X-ray units. METHODS Exposures were made with five different digital panoramic units, of which four were equipped with a direct digital CCD (charge coupled device, "direct digital" technique), and one used storage phosphor plates ("indirect digital" technique). An anthropomorphic phantom served as the patient. An ionization chamber recorded the scattered radiation at 1 m from the phantom at five different locations around the panoramic units, both at the level of the thyroid gland and the level of the gonads, and effective organ doses were calculated. Exposure parameters were set as recommended by the manufacturers for the particular image and patient size: tube potential settings ranged between 64 kV and 74 kV, exposure times between 8.2 s and 19.0 s, tube current values between 4 mA and 7 mA. RESULTS The maximum organ equivalent dose at 1 m from the panoramic unit was 0.60 microGy, the maximum organ effective dose was 0.10 microSv. Organ equivalent doses varied between 0.18 microGy and 0.30 microGy and organ effective doses between 0.01 microSv and 0.05 microSv for the different positions around the units (average for the different panoramic units). The variations in organ doses for the various machines were 0.04-0.53 microGy organ equivalent dose and 0.01-0.08 microSv organ effective dose. CONCLUSIONS Assuming that 500 panoramic radiographs per year are taken by a dental practitioner at 1 m distance from the panoramic unit, he or she will receive an annual additional organ effective dose between 5 microSv and 15 microSv for the thyroid gland and between 5 microSv and 40 microSv for the gonads, depending on the type of digital panoramic unit.
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Affiliation(s)
- F Gijbels
- Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Katholieke Universiteit Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium
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Lahm R, Iaizzo PA. Physiologic responses during rest on a sleep system at varied degrees of firmness in a normal population. ERGONOMICS 2002; 45:798-815. [PMID: 12487692 DOI: 10.1080/00140130210159968] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This study explores the hypothesis that a high degree of sustained muscle activity associated with a sub-optimal spinal orientation may compromise an individual's ability to relax or initiate sleep. Data from 22 participants who were considered to be part of a normal, back-pain-free population were used in these studies. Participants laid down on a mattress in a foetal position (i.e. on their sides) at three varying bed pressures while EMG activities, heart rates, blood pressures, subjective comfort levels and spinal alignment data were recorded. Minor effects of mattress inflation pressures were associated with changes in EMG activity, heart rate, blood pressure and/or subjective comfort. In contrast, spinal alignment assessment revealed significant differences between the three different inflation pressures studied (827.4, 2413.2 and 3999.0 Pa). It was concluded that in a population of normal participants, although mattress inflation pressure induced significant changes in spinal alignment, these changes were of little physiological consequence. Nevertheless, this data provides baseline information needed to assess similar correlations in a symptomatic population (e.g. those with either acute or chronic neck or back pain).
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Affiliation(s)
- Ryan Lahm
- Department of Biomedical Engineering, University of Minnesota, MN 55455, USA
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Hallquist A, Näsman A. Medical diagnostic X-ray radiation--an evaluation from medical records and dentist cards in a case-control study of thyroid cancer in the northern medical region of Sweden. Eur J Cancer Prev 2001; 10:147-52. [PMID: 11330455 DOI: 10.1097/00008469-200104000-00005] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of this study was to evaluate the association between thyroid cancer and diagnostic X-ray radiation based on medical records. By using the Swedish Cancer Registry, 187 living cases with thyroid cancer (81%), aged 20-70 years at the time of their diagnosis in 1980-1989 were identified in the Northern Health Care Region of Sweden. Seven cases were reclassified as having a disease other than thyroid cancer and were excluded. The investigation included 180 living cases and 360 controls from the National Population Registry. In 132 cases and 251 controls data from X-ray records on earlier investigations > 5 years prior to diagnosis and corresponding years for the controls were analysed. The mean calculated thyroid dose for the cases was 7.0 mGy (median 1.1) and for the controls 7.4 mGy (median 1.0). This study showed no difference in the total material between calculated absorbed thyroid dose of medical diagnostic X-ray in cases versus controls. In younger women (< or = 50 years at diagnosis) with papillary thyroid cancer an association was found, however it was not significant. The results could be related to selective bias and should be treated with caution. Future studies require analysis of diagnostic medical X-ray investigations involving the thyroid gland including more specific data on sex and age of exposure in the whole study group.
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Affiliation(s)
- A Hallquist
- Department of Oncology-Pathology, Karolinska Institute, Radiumhemmet, Stockholm, Sweden.
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Sont WN, Zielinski JM, Ashmore JP, Jiang H, Krewski D, Fair ME, Band PR, Létourneau EG. First analysis of cancer incidence and occupational radiation exposure based on the National Dose Registry of Canada. Am J Epidemiol 2001; 153:309-18. [PMID: 11207146 DOI: 10.1093/aje/153.4.309] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A cohort study was conducted to investigate the relation between cancer incidence and occupational exposure to ionizing radiation. Records containing dose information from 1951 to 1988 for 191,333 persons were extracted from the National Dose Registry of Canada. The records were linked to the Canadian Cancer Data Base, with incidence data from 1969 to 1988. Standardized incidence ratios were calculated using Canadian cancer incidence rates stratified by age, sex, and calendar year. Excess relative risks were obtained from internally based dose-response analyses. The following significant results were found for males and females combined: a deficit in the standardized incidence ratio for all cancers combined; elevated standardized incidence ratios for thyroid cancer and melanoma; and elevated excess relative risks for rectum, leukemia, lung, all cancers combined, all except lung, and all except leukemia. For males, cancers of the colon, pancreas, and testis also showed significantly elevated excess relative risks. The specific cancer types listed above have been implicated in previous studies on occupational exposure to ionizing radiation, except for testis, colon, and melanoma, while the findings on thyroid cancer from previous studies are inconclusive. The thyroid standardized incidence ratios in this study are highly significant, but further investigation is needed to assess the possibility of association with occupational radiation exposure.
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Affiliation(s)
- W N Sont
- Radiation Protection Bureau, Health Canada, Ottawa, Ontario.
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Abstract
OBJECTIVES Veterinarians come into contact with several potentially carcinogenic exposures in the course of their occupation. These exposures include radiation, anaesthetic gases, pesticides (particularly insecticides), and zoonotic organisms. This review aims to summarise what is known about the carcinogenic risks in this profession. METHODS The levels of exposure to potential carcinogens in the veterinary profession are examined and evidence is reviewed for carcinogenesis of these substances in humans at doses similar to those experienced by veterinarians. The few published studies of cancer in veterinarians are also summarised. RESULTS Veterinarians have considerable potential for exposure to several known and potential carcinogens. Risks may be posed by work in clinics with poorly maintained x ray equipment, by use of insecticides, and from contact with carcinogenic zoonotic organisms. The few studies available suggest that veterinarians have increased mortality from lymphohaematopoietic cancers, melanoma, and possibly colon cancer. CONCLUSIONS The exposures examined in this review are not unique to the veterinary profession, and, as a consequence, information gathered on the carcinogenic risks of these exposures has implications for many other occupations such as veterinary nurses, animal handlers, and some farmers, as well as dentists, radiographers, and anaesthetists.
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Affiliation(s)
- L Fritschi
- Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Prahran 3181, Australia.
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Scarpato R, Lori A, Tomei A, Cipollini M, Barale R. High prevalence of chromosome 10 rearrangements in human lymphocytes after in vitro X-ray irradiation. Int J Radiat Biol 2000; 76:661-6. [PMID: 10866288 DOI: 10.1080/095530000138321] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
PURPOSE To evaluate the chromosome symmetric or asymmetric rearrangement (CR) frequency for chromosome 10 compared to chromosomes 1 and 3 induced in vitro in human lymphocytes by low doses of X-rays. MATERIALS AND METHODS Blood samples obtained from three young and healthy volunteers were irradiated in G0 with 0.25, 0.50 and 1 Gy X-rays. Chromosome painting analysis was used on preparations of peripheral lymphocytes for the identification of CR. RESULTS It was found that radiation-induced CR levels were nonrandomly distributed among the three painted chromosomes. Chromosome 10 CR frequencies were significantly greater than those involving chromosomes 1 (at all the doses tested) or 3 (at 0.25 and 1 Gy), with frequency ratios ranging from 2.2 to 5.2. CONCLUSIONS In comparison to chromosomes 1 and 3, chromosome 10 appeared to be involved in exchanging at a significantly greater extent than expected according to its DNA content.
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MESH Headings
- Analysis of Variance
- Chromosome Aberrations
- Chromosomes, Human, Pair 1/genetics
- Chromosomes, Human, Pair 1/radiation effects
- Chromosomes, Human, Pair 10/genetics
- Chromosomes, Human, Pair 10/radiation effects
- Chromosomes, Human, Pair 3/genetics
- Chromosomes, Human, Pair 3/radiation effects
- Dose-Response Relationship, Radiation
- Humans
- In Situ Hybridization, Fluorescence
- Lymphocytes/radiation effects
- Male
- X-Rays
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Affiliation(s)
- R Scarpato
- Dipartimento di Scienze dell'Uomo e dell'Ambiente, Università degli Studi di Pisa, Italy
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