Nano Archive

Fabrication of high aspect-ratio polymer microstructures for large-area electronic portal X-ray imagers

Daniel, J. H. and Sawant, A and Teepe, M and Shih, C and Street, R. A. and Antonuk, L. E. (2007) Fabrication of high aspect-ratio polymer microstructures for large-area electronic portal X-ray imagers. Sensors and Actuators A: Physical, 140 (2). 185 - 193.

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Megavoltage X-ray imaging performed during radiotherapy is the method of choice for geometric verification of patient localization and dose delivery. Presently, such imaging is increasingly performed using electronic portal imaging devices (EPIDs) based on indirect detection active matrix flat panel imagers (AMFPIs). These devices use a scintillating phosphor screen in order to convert incident X-rays into optical photons, which are then detected by the underlying active matrix photodiode array. The use of a continuous phosphor introduces a trade-off between X-ray quantum efficiency and spatial resolution, which limits current devices to use only 2% of the incident X-rays. This trade-off can be circumvented by “segmented phosphor screens”, comprising a two-dimensional matrix of optically isolated cell structures filled with scintillating phosphor. In this work we describe the fabrication of mm-thick segmented phosphor screens using the MEMS (micro-electro-mechanical-system) polymer SU-8. This method is capable of being extended to large-area substrates.

Item Type:Article
Uncontrolled Keywords:High aspect-ratio; SU-8; X-ray imaging; Large-area MEMS; Polymer MEMS; Scintillator
Subjects:Material Science > Nanofabrication processes and tools
Analytical Science > Nanotechnology for sensing and actuating
Analytical Science > Metrology and standards in nanotechnology
Material Science > Nanostructured materials
ID Code:4875
Deposited By:SPI
Deposited On:24 Apr 2009 15:24
Last Modified:24 Apr 2009 15:24

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