By: Dr. Susanne M. Savely, RSO, Baylor College of Medicine, STC-HPS Past-President
The Texas Medical Center-based News in Radiation Safety (NIRDS) met on 11-17-2017, to discuss the recent National Council on Radiation Protection and Measurements (NCRP) recommendation regarding the reduction of the dose limit to the lens of the eye. Attendees included representatives from The University of Texas Health Science Center at Houston, Baylor College of Medicine, Baylor CHI St. Luke’s Medical Center, Harris Health System, Houston Methodist, Houston Methodist Research Institute, Memorial Hermann, Michael E. DeBakey Veteran Affairs Medical Center, Texas Children’s Hospital, and The University of Texas MD Anderson Cancer Center.
The Texas Medical Center (TMC) is the largest medical complex in the world. It is composed of 46 member institutions, including the largest children’s and cancer hospitals in the world. The TMC is the 8th largest business district in the U.S., where over 10 million patients are seen per year. In addition to the provision of medical care, the TMC is at the forefront of advancing life sciences, nurturing cross-institutional collaboration.
The NCRP has recently recommended a change in the annual limit of radiation dose to the lens of the eye due to new information on potential effects. “The NCRP determined that it is prudent to reduce the recommended annual occupational dose limit for the lens of the eye from an equivalent dose of 150 mSv (or 15,000 mrem - more familiar units added here for comparison) to an absorbed dose of 50 mGy (or 5,000 mrem - more familiar units added here for comparison). The NCRP added, “In fluoroscopically guided interventional and cardiac procedures, the use of adequate eye protection is a necessity."
This recommendation could affect personnel who regularly perform highly-involved interventional fluoroscopic procedures. During the group meeting, various radiation safety professionals reported that no other employees receive doses to their eyes at levels near the existing or recommended limit. Most other radiation workers in the research and clinical setting receive less than 500 mrem annually, or less than 10% of the annual recommended maximum. Currently, this dose reduction is a recommendation, but it is assumed that it will be most likely adopted at some point by federal and state authorities. Currently, some TMC work locations provide leaded eyewear for use during interventional fluoroscopy, and others ask that users buy their own through their departments.
Dr. Lou Wagner, RSO for the LBJ Hospital of the Harris Health System, presented on the “Possible Harmonization of Personal Dosimetry ALARA Investigation Levels for Clinically Exposed Healthcare Workers across Texas Medical Center Member Organizations.” He and Dr. Bob Emery (aka “Safety Bob”), RSO for the UT Health Science Center at Houston, led a discussion among the 22 other attendees. Drs. Ben Archer (X-ray RSO, Harris Health), Lou Wagner, and Bob Emery are proposing adoption across the TMC of the following ALARA levels for clinical healthcare providers:
Calendar quarterly interval
|Cumulative (year to date) recorded dose (mrem)|
|Lens dose||Deep body dose
(with R2 calculation applied)
|First quarter ending March 31||1,000||1,000|
|Second quarter ending June 30||2,000||2,000|
|Third quarter ending September 30||3,000||3,000|
|Fourth quarter ending December 31||4,000||4,000|
The ensuing discussion revealed that some organizations are reviewing dosimetry reports and comparing them to their pre-set ALARA levels on a monthly or quarterly basis, as opposed to the cumulative method above. Most expressed concern about radiation dosimeter wear compliance and current and upcoming compliance with leaded eyewear recommendations. Dr. Wagner revealed that he will be asking the Chief Technicians in the LBJ Hospital (Harris Health) interventional fluoroscopy labs to record who is wearing their dosimeter(s) and who is wearing their eyewear in the absence of an RSO presence in the labs. The NIRDS agreed that there was a need to continue to increase awareness about the important of compliance with dosimetry and PPE requirements.
Action items that resulted from the discussion include:
Drs. Ben Archer, Lou Wagner, and Bob Emery are hoping that the adoption across the TMC of the ALARA levels proposed above for clinical healthcare providers will aid in data collection and comparison. It is hoped that the resulting harmonization of ALARA levels and subsequent data generated will streamline future interactions with the TDSHS on implementation of the upcoming legislation regarding eye lens dose. Lunch at the 12–1 p.m. meeting was generously provide by the UT Health Science Center at Houston.