Quantification of manganese in human hand bones: a feasibility study

Area of Science:

• Environmental Health
• Biomedical Engineering
• Nuclear Physics

Background:

• Manganese (Mn) is essential but toxic at high levels, with inhalation being a primary exposure route.
• Biological monitoring of Mn exposure is challenging due to homeostasis, where blood levels quickly normalize.
• Measuring stored Mn in bone offers a more stable indicator of cumulative exposure.

Purpose of the Study:

• To develop and enhance a non-invasive in vivo neutron activation analysis (NAA) technique for measuring manganese in bone.
• To address spectral interferences from magnesium (Mg) in bone during NAA.
• To establish referent levels of manganese in bone for non-exposed individuals.

Main Methods:

• Utilized enhanced in vivo neutron activation analysis (NAA) with a specialized irradiation facility and a near 4π detection system.
• Measured manganese in the bones of the hand, accounting for spectral interference from magnesium.
• Estimated referent manganese levels in bone based on revised literature data.

Main Results:

• Achieved a detection limit of 1.6 µg/g Ca for manganese in the hand.
• Revised the estimated referent level of manganese in bone to 0.63 µg/g Ca.
• Demonstrated significant technical improvements in the NAA system for manganese measurement.

Conclusions:

• The enhanced in vivo NAA technique provides a promising non-invasive method for assessing manganese exposure by measuring bone manganese levels.
• Further technical improvements are needed to extend the application of this technique for in vivo measurements in non-exposed human subjects.
• This method has potential for screening individuals with excessive manganese exposure.