Photoresists as a high spatial resolution autoradiography substrate for quantitative mapping of intra- and sub-cellular distribution of Auger electron emitting radionuclides

AbstractPurpose: To explore poly(methyl methacrylate) (PMMA950) as an autoradiography substrate.Materials and methods: PMMA950 was spin coated onto a silicon substrate. Resists were exposed to either a 25 or 50 keV electron beam (e-beam) with fluences of 0.1–33.6 μC/cm2. The resulting patterns were analyzed by atomic force microscopy (AFM). The dependence of pattern sensitivity and resolution on resist thickness, development time and electron energy was evaluated and correlated with Monte Carlo (MC) modeling. Conventional micro-autoradiography (MAR) images were compared to AFM images of photoresist patterns obtained following exposure from 111In-diethylenetriaminepentaacetic acid (DTPA)-human epidermal growth factor (hEGF) (4–6 MBq/μg, 40 nM DTPA-hEGF)-treated human breast cancer cells MDA-MB-468.Results: MC simulation results confirmed the similarity of particle transport in PMMA950 exposed to either an 111In point source or a 25 keV e-beam. Sensitivity was inversely related to resist thickness. Developm...