Nuclear medicine annual external occupational dose distribution: Rio de Janeiro, Brazil, year 2005

Area of Science:

• Medical Physics
• Occupational Health
• Radiological Protection

Background:

• Brazil has approximately 300 nuclear medicine services (NMS), with 44 located in Rio de Janeiro (RJ).
• Routine external dose monitoring is standard practice for most nuclear medicine personnel.
• The increasing number of professionals and their occupational doses in nuclear medicine necessitates ongoing safety assessments.

Purpose of the Study:

• To statistically analyze the annual external occupational doses for nuclear medicine staff in Rio de Janeiro (RJ) during 2005.
• To evaluate compliance with regulatory dose limits and identify areas for radiation protection improvement.

Main Methods:

• Statistical analysis of annual external occupational doses recorded in 2005 for all RJ NMS.
• Comparison of individual doses against the mean annual dose limit of 20 mSv.
• Analysis of extremity dosemeter usage and extremity-to-thorax dose ratios.

Main Results:

• Approximately 100 professionals in RJ NMS received annual external doses exceeding 4.0 mSv.
• No staff member exceeded the annual dose limit of 20 mSv.
• Extremity doses, measured by dosemeters used by about 10% of staff, were in some cases over 10 times higher than thorax doses, with a maximum ratio of 72:1.

Conclusions:

• While no staff exceeded the annual dose limit, a significant number received doses above 4.0 mSv.
• The high extremity-to-thorax dose ratios highlight potential deficiencies in radiation protection practices for certain procedures.
• There is a clear need to enhance radiation protection strategies in nuclear medicine, particularly concerning extremity dosimetry and monitoring, due to increasing occupational exposures.