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

J. H. Daniel, A. Sawant, M. Teepe, C. Shih, R. A. Street, L. E. Antonuk

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)185-193
Number of pages9
JournalSensors and Actuators, A: Physical
Issue number2
StatePublished - Nov 10 2007


  • High aspect-ratio
  • Large-area MEMS
  • Polymer MEMS
  • SU-8
  • Scintillator
  • X-ray imaging

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering


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