Development and Validation of a Novel In Vivo Neutron Activation Analysis Technology for Noninvasive Quantification of Manganese in Bone

Details

• Personal Author:
  Nie LH ; Wells E ; Zheng W
• Description:
  Millions of workers, including over 500,000 welders employed in the United States, have been exposed to excessive metals. Human and animal studies have linked metal exposure to various health outcomes, especially neurophysiological disorders and neurodegenerative diseases. Manganese (Mn) is a well known neuro-toxicant due to both occupational and environmental exposures. Ample evidence has demonstrated neurotoxicities induced by exposure to Mn among welders and other populations. However, the threshold of Mn exposure, the mechanism of the toxicity of Mn, and the interaction of Mn with other metals (such as lead, mercury, copper, iron, and zinc) are unknown and therefore deserve further investigation. One pending issue in assessment of Mn exposure pertains to the selection of a proper biomarker. Over 40% of Mn in human body is stored in bone, which renders bone Mn to be the ideal biomarker to assess cumulative Mn in the body with long-term, low dose exposure, a pattern typically seen among workers occupationally exposed to Mn. There is no practical way at present to asses Mn levels in bone. In this project, we developed and validated a transportable neutron activation analysis (NAA) system to measure bone Mn (MnBn) in vivo. The system consists of two parts: a compact DD neutron generator with a flux of up to 3 * 109 neutrons/ sec for irradiation, and a 100% HPGe detector system for Mn gamma ray detection. Optimized settings, including moderator, reflector, and shielding material and thickness, were selected based on Monte Carlo (MC) simulations conducted in our previous work. Hand phantoms doped with different Mn concentrations were used to calibrate the system. The phantoms were irradiated using the optimized DD neutron generator irradiation system. The Mn characteristic y-rays were collected by the high efficiency HPGe detector system. The calibration line of the Mn/calcium (Ca) count ratio versus bone Mn concentration was obtained (R2 = 0.99) using the hand phantoms. The detection limit was calculated to be about 0.43 ug Mn/g dry bone (ppm) with an irradiation dose of 36 mSv to the human hand. The detection limit can be reduced to 0.3 ppm with two 100% HPGe detectors. Given the average normal bone Mn concentration of 1 ppm in the general population, this system is promising for in vivo bone Mn quantification in humans. We have been conducting pilot studies to test the association between MnBn and neurological test scores among occupational populations. [Description provided by NIOSH]
• Subjects:
  Biomarkers Copper Environmental Exposure Ferrous Compounds Lead Manganese Mercury Metals Nervous System Nervous System Diseases Occupational Health Risk Assessment Risk Factors Safety Welding

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• Keywords:
  Bone Marrow Bone Structure Environmental Exposure Exposure Levels Gamma Rays Health Effects In Vivo Study Iron Iron Compounds Metal Compounds Metallic Compounds Neurological Diseases Neurological Disorders Neurophysiological Effects Neurotoxic Effects Neurotoxins Risk Factors Welders Workers Zinc Zinc And Compounds

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• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  Indiana ; OSHA Region 3 ; OSHA Region 5 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-17
• NIOSHTIC Number:
  nn:20048876
• NTIS Accession Number:
  PB2017-101416
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-010044, 2015 Sep; :1-17
• Contact Point Address:
  Linda H. Nie, School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906
• Email:
  hnie@purdue.edu
• CAS Registry Number:
  Copper (CAS RN 7440-50-8) ; Iron (CAS RN 7439-89-6) ; Lead (CAS RN 7439-92-1) ; Manganese (CAS RN 7439-96-5) ; Mercury (CAS RN 7439-97-6) ; Zinc (CAS RN 7440-66-6)
• Federal Fiscal Year:
  2015
• Performing Organization:
  Purdue University, West Lafayette, Indiana
• Peer Reviewed:
  False
• Start Date:
  20120701
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20150630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:5290fb757421291b19d83db404e5b888c7050a5db2670acfc757abb74e2d8cd4a8fe38e553364ce4dbac5b8eabcf8d9761f3cf400426ac114b7e006a01f4e1b5
• Download URL:
  https://stacks.cdc.gov/view/cdc/218650/cdc_218650_DS1.pdf
• File Type:
  [PDF - 529.61 KB ]