1. 2018;21;E523-E532Ionizing Radiation Dose Exposure to the Ocular Region of Pain Physicians During C-arm Guided Pain Interventions
   Observational Study
   Raymond Kelly, MB, Aisling McMahon, BSc, and Dominic Hegarty, MB, PhD.

BACKGROUND: The growth of interventional pain medicine in recent years has resulted in more procedures being carried out under fluoroscopic guidance. The proximity of the pain physician (PP) to ionization radiation (IR) potentially increases the risk of radiation exposure to the ocular region. A European directive has reduced the limits of occupational ocular dose 7.5-fold.

OBJECTIVES: The objectives of this study are to quantify the typical IR exposure in the ocular region of PP and to compare it to recommended international guidelines.

STUDY DESIGN: Three consultants involved in the pain unit service were enrolled in the study to reflect the dose implications involved with different caseloads, training obligations, and procedure types. All 3 consultants were experienced primary operators.

SETTING: The study was undertaken at the pain management suite in the South Infirmary Victoria University Hospital (SIVUH). Annually, this unit performs 2,800 fluoroscopic guide pain procedures.

METHODS: Thermoluminescent dosimeters (TLDs) calibrated to measure eye lens doses [Hp (0.07)] and whole-body doses (WBDs) were fitted to 3 pain consultants while they undertook imaging-guided pain procedures using mobile C-arm fluoroscopy over a 3-month period. The duration of radiation exposure, screening time (seconds), and procedure type were recorded. Radiation dose was calculated to estimate the effective radiation dose to the ocular region using (i) dose-area product (DAP) in milliGray per centimeter squared (mGycm2) and (ii) Air Kerma (AK) values in mGy.

RESULTS: IR doses were effectively recorded in 682 cases over 3 months and the data extrapolated. The estimated annual lens dose experienced by pain physicians performing fluoroscopy-guided procedures is less than the recommended international guidelines. A significant linear relationship between screening time and IR exposure was estimated (rs = 0.93, P < 0.01)

LIMITATIONS: In many centers, including our own, fluoroscopy procedures are undertaken by nonconsultant staff. Therefore, a small single-center cohort recruiting experienced consultant staff and not including pain fellows or registrars/residents with varying levels of experience is a limitation.

CONCLUSION: While IR to the ocular region was significantly less than the recommended European safety guidelines, the annual dose needs to be confirmed in pain physicians with a lesser degree of clinical experience.

KEY WORDS: Ionizing radiation, ocular, radiation protection, pain medicine, interventional