RSNA 2004 

Abstract Archives of the RSNA, 2004


SSJ19-01

Sensitivity of Personal Homeland Security Radiation Detectors to Medical Radionuclides and Implications for Counseling of Nuclear Medicine Patients

Scientific Papers

Presented on November 30, 2004
Presented as part of SSJ19: Physics (Nuclear Medicine, PET, MR Imaging)

Participants

Lionel S. Zuckier MD, Presenter: Nothing to Disclose
Michael G. Stabin PhD, Abstract Co-Author: Nothing to Disclose
Gary S Garetano, Abstract Co-Author: Nothing to Disclose
Matthew A Monetti, Abstract Co-Author: Nothing to Disclose
Venkata K. Lanka, Abstract Co-Author: Nothing to Disclose

PURPOSE

Increasing deployment of radiation detectors designed to identify and interdict illicit radioactive sources has led to a phenomenon of patients being detected and investigated by emergency responders following administration of therapeutic and even diagnostic radiopharmaceuticals. We wish to assess the potential duration of this problem by analyzing sensitivity of detectors to medical radionuclides and applying this information to pharmacokinetic models of radiopharmaceutical excretion.

METHOD AND MATERIALS

Five personal radiation detectors, culled from operational units in the field, were studied: Pocket Pager (2 units), Pocket Pager-S and HRM, (all Sensor Technology Engineering, Inc., Santa Barbara, CA) and PM1703M (ThermoElectron Corporation, Minsk, Republic of Belarus). Calibrated amounts of 7 medically-relevant radionuclides (Tl-201, Tc-99m, Ga-67, I-123, In-111, I-131, F-18) were tested against the panel of detectors to determine levels at which they alarm. Approximately 100μCi of each radionuclide was translated towards the detectors at 0.5m increments and the distance at which each detector alarmed was noted. Using the gamma ray constant Γ, the triggering exposure rate was determined. This was compared to administered activity levels and pharmacokinetic models of excretion for diagnostic and therapeutic radiopharmaceuticals to assess potential alarm triggering at a 1m survey distance.

RESULTS

At standard operational settings, detectors exhibit similar sensitivity, alarming at rates between ~0.5 and 8 μR/hr in a photon energy-dependent manner. After 1 day F-18 FDG is below triggering levels. Patients administered Tc-99m radiopharmaceuticals or I-123 NaI may trigger these alarms for up to 3 days, In-111 WBC and platelets for 14-17 days, Ga-67 citrate and Tl-201 thallous chloride for up to ~30 days, and I-131 containing NaI and Bexxar for up to 95 days.

CONCLUSIONS

Personal radiation detectors used for Homeland Security are extremely sensitive and may detect low levels of radionuclides for prolonged periods of time. Patients should be appropriately counseled to carry information regarding administration of diagnostic and therapeutic radiopharmaceuticals for these extended periods.

Cite This Abstract

Zuckier, L, Stabin, M, Garetano, G, Monetti, M, Lanka, V, Sensitivity of Personal Homeland Security Radiation Detectors to Medical Radionuclides and Implications for Counseling of Nuclear Medicine Patients.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4407767.html