Reliance on simulations for dose estimates in therapeutic and diagnostic nuclear medicine arises from a general acceptance of the idea that physical measurements of dose (a bulk quantity) at the relevant (molecular) scale are impossible. Despite acknowledgement that physical data are highly desirable for the enhancement of efficacy and safety, researchers and clinicians alike have resigned themselves to the notion that direct meaningful measurement of the distribution of ionization tracks in nanometric volumes is impossible. In the Radioactivity Group at NIST, we are addressing this metrology challenge, demonstrating that physical measurements of absorbed dose can be made at the nanoscale. We utilize advanced experimental and Monte Carlo methods to quantify energy losses within biomolecule-containing reverse micelles in liquid scintillation (LS) cocktails. The project involves the identification/development of cocktail formulations with high counting efficiencies and biomolecular loading capacities; the characterization of micelle size distributions in LS cocktails by dynamic light scattering; the application of efficiency-tracing techniques to biomolecular LS samples; and Monte Carlo simulations of energy loss mechanisms within well-characterized cocktails. The goal of the project is to provide better benchmarking of dose models and a real metrological basis for the calculations that underlie so much of modern cancer diagnosis and treatment.

 

References

Bergeron DE: Applied Radiation and Isotopes doi:10.1016/j.apradiso.2012.02.089 (2012)

Bergeron DE, Zimmerman BE, Cessna JT: Applied Radiation and Isotopes 68: 1367, 2010

 

Keywords:

Liquid scintillation spectrometry; Radionuclide metrology; Radiation damage; Dosimetry; Reverse micelle; Nanomedicine; Nuclear medicine; Monte Carlo; Dynamic light scattering;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants