Slit design for efficient and accurate MTF measurement at megavoltage xâ ray energies

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135139/1/mp7405.pd

Erratum: â Strategies to improve the signal and noise performance of active matrix, flatâ panel imagers for diagnostic xâ ray applicationsâ [Med. Phys. 27, 289â 306 (2000)] and â Determination of the detective quantum efficiency of a prototype, megavoltage indirect detection, active matrix flatâ panel imagerâ [Med. Phys. 28, 2538â 2550 (2001)]

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134876/1/mp5910.pd

Theoretical investigation of the design and performance of a dual energy (kV and MV) radiotherapy imager

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134977/1/mp5120.pd

System performance of a prototype flatâ panel imager operated under mammographic conditions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135010/1/mp5051.pd

Empirical noise performance of prototype active pixel arrays employing polycrystalline silicon thin- film transistors

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162751/2/mp14321.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162751/1/mp14321_am.pd

Monte Carlo investigations of megavoltage coneâ beam CT using thick, segmented scintillating detectors for soft tissue visualization

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134940/1/mp8957.pd

Low-dose megavoltage cone-beam CT imaging using thick, segmented scintillators

Megavoltage, cone-beam computed tomography (MV CBCT) employing an electronic portal imaging device (EPID) is a highly promising technique for providing soft-tissue visualization in image-guided radiotherapy. However, current EPIDs based on active matrix flat-panel imagers (AMFPIs), which are regarded as the gold standard for portal imaging and referred to as conventional MV AMFPIs, require high radiation doses to achieve this goal due to poor x-ray detection efficiency (~2% at 6 MV). To overcome this limitation, the incorporation of thick, segmented, crystalline scintillators, as a replacement for the phosphor screens used in these AMFPIs, has been shown to significantly improve the detective quantum efficiency (DQE) performance, leading to improved image quality for projection imaging at low dose. Toward the realization of practical AMFPIs capable of low dose, soft-tissue visualization using MV CBCT imaging, two prototype AMFPIs incorporating segmented scintillators with ~11 mm thick CsI:Tl and Bi 4 Ge 3 O 12 (BGO) crystals were evaluated. Each scintillator consists of 120 _ 60 crystalline elements separated by reflective septal walls, with an element-to-element pitch of 1.016 mm. The prototypes were evaluated using a bench-top CBCT system, allowing the acquisition of 180 projection, 360° tomographic scans with a 6 MV radiotherapy photon beam. Reconstructed images of a spatial resolution phantom, as well as of a water-equivalent phantom, embedded with tissue equivalent objects having electron densities (relative to water) varying from ~0.28 to ~1.70, were obtained down to one beam pulse per projection image, corresponding to a scan dose of ~4 cGy–-a dose similar to that required for a single portal image obtained from a conventional MV AMFPI. By virtue of their significantly improved DQE, the prototypes provided low contrast visualization, allowing clear delineation of an object with an electron density difference of ~2.76%. Results of contrast, noise and contrast-to-noise ratio are presented as a function of dose and compared to those from a conventional MV AMFPI.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90773/1/0031-9155_56_6_001.pd

Signal, noise power spectrum, and detective quantum efficiency of indirectâ detection flatâ panel imagers for diagnostic radiology

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135120/1/mp8243.pd

An investigation of signal performance enhancements achieved through innovative pixel design across several generations of indirect detection, active matrix, flatâ panel arrays

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134990/1/mp9602.pd