Numerical evaluation of high-energy, laser-Compton x-ray sources for contrast enhancement and dose reduction in clinical imaging via gadolinium-based K-edge subtraction.

Conventional x-ray sources for medical imaging utilize bremsstrahlung radiation. These sources generate large bandwidth (BW) x-ray spectra with large fractions of photons that impart a dose, but do not contribute to image production. X-ray sources based on laser-Compton scattering can have inherently small energy BWs and can be tuned to low dose-imparting energies, allowing them to take advantage of atomic K-edge contrast enhancement. This paper investigates the use of gadolinium-based K-edge subtraction imaging in the context of mammography using a laser-Compton source through simulations quantifying contrast and dose in such imaging systems as a function of laser-Compton source parameters. Our simulations indicate that a K-edge subtraction image generated with a 0.5% BW (FWHM) laser-Compton x-ray source can obtain an equal contrast to a bremsstrahlung image with only 3% of the dose.

Computational method for the optimization of quasimonoenergetic laser Compton x-ray sources for imaging applications.

The development of compact quasimonoenergetic x-ray radiation sources based on laser Compton scattering (LCS) offers opportunities for novel approaches to medical imaging. However, careful experimental design is required to fully utilize the angle-correlated x-ray spectra produced by LCS sources. Direct simulations of LCS x-ray spectra are computationally expensive and difficult to employ in experimental optimization. In this manuscript, we present a computational method that fully characterizes angle-correlated LCS x-ray spectra at any end point energy within a range defined by three direct simulations. With this approach, subsequent LCS x-ray spectra can be generated with up to 200 times less computational overhead.

Use of Supramolecular Assemblies as Lithographic Resists.

A new resist material for electron beam lithography has been created that is based on a supramolecular assembly. Initial studies revealed that with this supramolecular approach, high-resolution structures can be written that show unprecedented selectivity when exposed to etching conditions involving plasmas.