Fabrication of Large Area, Submicron and Deep Submicron Hard X-Ray Gratings

PROJECT SUMMARY ABSTRACT Grating based x ray interferometric imaging has long been considered a promising technique to significantly enhance image quality at reduced radiation doseby detecting phase and scattering contrasts in addition to the absorptionX ray gratings are central components in x ray interferometersCommercially available x ray gratings have periods of andgtmwhich limits the sensitivity enhancement to a level that the dose reduction enabled by interferometric imaging is not obvious for practical applicationsLaboratorymade deep submicron period x ray gratings have been used in prototype imaging systems to improve the imaging sensitivity by an order of magnitudeThe small area of the gratings and the challenges to fabricate large area gratings limit the clinical applications of such imaging systemsThe goal of this project is to develop a batch fabrication process to manufacture large areasubmicron and deep submicron period x ray phase gratings at energy levels up tokeV for various applicationsThe proposed research in Phase I will focus on fabrication of x ray gratings for breast imaging applications at a central energy level ofkeVBreast cancer is the top cancer in women worldwideEarly detection and treatment improve breast cancer outcome and survivalparticularly before the cancer metastasizesDigital mammography is the most popularly used imaging method for early detection of breast cancerAccording to National Cancer Institutethe sensitivity istoand the specificity isX ray interferometric imaging with submicron period gratings provides a promising solution to improve both the sensitivity and precision by combining the three contrast mechanismsthus reducing both false negative and false positive ratesThe lack of large areasubmicron and deep submicron period gratings limit the further development of such imaging systemsGeneral Optics proposes to bring such gratings to the market through developing a cost efficient batch fabrication processThe specific aims of Phase I research aredevelop a process to fabricatenm periodphase shift x ray gratings atkeV with an area ofcm xcmdevelop a doublefrequency process to producenm periodphase shift x ray gratings atkeVinvestigate the performance of these gratings via x ray diffraction testThe investigation of the grating performance in xray interferometersoptimization of the grating profiles for better x ray interferometer performancefurther reduction of the grating period tonm and the extension tokeVphase shift x ray gratings would be the next stage of this SBIR Phase I project PROJECT NARRATIVE The rapidly increasing utilization of x ray imagingwhich accounts for the majority of medical diagnostic procedureshas led to major concerns about the population radiation doseX ray phase contrast imaging with submicron period gratings provides a promising solution to significantly reduce the radiation dose by detecting the x ray phase and scattering contrasts in addition to the absorptionThe goal of this project is to bring one of a kind large areasubmicron and deep submicron period x ray gratings to the market to facilitate the development of highly sensitive x ray phase contrast imaging systems for various biomedical imaging applications