Room: AAPM ePoster Library
Purpose: To evaluate the radiation safety of out-patient Lutathera treatment.
Methods: Descriptive statistics were computed for the measured exposure rate at 1 m (X), time of release (Trel), durations of radiation precautions and estimated total effective dose equivalents (TEDEs). Our release calculations use one fourth of the regulatory TEDE limits because the same persons might be exposed during all four cycles of a course of treatment; X measured with a calibrated ion chamber survey meter; and a 56.1 h average second-phase whole body clearance effective half-life (C Wehrmann et al. Cancer Biother Radiopharm 2007;23:406–16). Patient-specific radiation precaution durations for and estimated TEDE to the most-exposed person, children, pregnant women and fellow travelers were calculated using NUREG 1556 Vol 9 Rev 2 App U, JA Siegel et al. (J Nucl Med 2002;43:354–63), LR Cooper et al. (J Nucl Med 2000;41:1868–75) and answers to lifestyle questions. Per release mean±s and range (minimum - maximum) values from 292 treatments of 98 patients from July 2018 through January 2020 were calculated.
Activity prescription: 271 at 200 mCi, 21 at 100 mCi
X: 1.70±0.47, 0.80-3.10 mR/h (measured at 3.08±0.85, 0.95-5.23 hours)
Trel: 5.59±0.45, 4.53-7.50 hours
Sleep alone for: 4.44±1.20, 1.50-7.34 days
Limit time < 6 ft from children/pregnant women for: 3.41±1.24, 1.00-6.84 days
Stay > 6 ft from others for: 0.95±0.79, 0.00-2.95 days
Return to work or school after: 0.28±0.61, 0.00-2.82 days
Most-exposed Person TEDE: 37.5±9.4, 18.0-64.0 mrem
Children/Pregnant Women TEDE: 24.9±0.6, 19.0-25.0 mrem
Fellow Traveler TEDE: 8.9±7.6, 1.0-25.0 mrem
Conclusion: All TEDE estimates were less than 100 mrem and thus standard-of-care Lutathera patients can be released on the treatment day without radiation precaution instructions. Even quartering the limits of the most-exposed person and member of the public to 125 and 25 mrem, all of these patients could be released with instructions.