Magnetic resonance imaging (MRI) is being rapidly integrated for cancer treatments-such systems are referred to as MRI-guided radiation therapy (MRIgRT). As the magnet of an MRI scanner is always on, the presence of a strong static magnetic field from the MRI scanner during radiotherapy delivery presents new challenges. One of the challenges is that a personal radiation dosimeter used to estima...

Background: A variable resolution X-ray (VRX) CT scanner provides a great increase in the spatial resolution. In VRX CT scanners, the spatial resolution of the system and its field of view (FOV) can be changed according to the object size. One of the main factors that limit the spatial resolution of VRX CT scanner is the effect of the X-ray focal spot. Materials and Methods: A theoreti...

Continuous arterial spin labeling (ASL) using a locally induced magnetic field gradient for adiabatic inversion of spins in the common carotid artery of human volunteers is demonstrated. The experimental setup consisted of a helmet resonator for imaging, a circular RF surface coil for labeling, and gradient loops to produce a magnetic field gradient. A spin-echo (SE) echo-planar imaging (EPI) s...

T. Grafendorfer, N. I. Matter, R. D. Venook, S. E. Ungersma, G. E. Gold, N. J. Giori, B. A. Hargreaves, J. M. Pauly, A. Macovski, G. C. Scott, and S. M. Conolly GE Global Health, CA, Electrical Engineering, Stanford University, CA, Stanford University, CA, Radiology, Stanford University, CA, Orthopedic Surgery, Stanford University, CA, Bioengineering, UC Berkeley, Berkeley, CA, United States, E...

We demonstrate a new method whereby near-field optical microscope resolution can be extended to the nanometer regime. The technique is based on measuring the modulation of the scattered electric field from the end of a sharp silicon tip as it is stabilized and scanned in close proximity to a sample surface. Our initial results demonstrate resolution in the 3 nm range--comparable to what can be ...

This paper deals with self-calibration and its adaptation to structured light vision. A brief survey on selfcalibration for stereovision is first proposed. Then, after having described the geometry of a structured light sensor and the constraints it imposes, a method based on the generation of Euclidean constraints is detailed. It is mainly shown how the projection of a known pattern is used to...

Optical-resolution photoacoustic microscopy (OR-PAM) is an imaging tool to provide in vivo optically sensitive images in biomedical research. To achieve a small size, fast imaging speed, wide scan range, and high signal-to-noise ratios (SNRs) in a water environment, we introduce a polydimethylsiloxane (PDMS)-based 2-axis scanner for a flexible and waterproof structure. The design, theoretical b...

background and aims. digital radiographs have some advantages over conventional ones. application of digital receptors is not routine yet. therefore, there is a need for digitizing conventional radiographs. the aim of the present study was to compare the diagnostic accuracy of digitized conventional radiographs by scanner and camera in detection of proximal caries. material and methods. three h...

background: accurate small radiation field dosimetry is essential in modern radiotherapy techniques such as stereotactic radiosurgery (srs) and intensity modulated radiotherapy (imrt). precise measurement of dosimetric parameters such as beam profile, percentage depth doses and output factor of these beams are complicated due to the electron disequilibrium and the steep dose gradients. in the p...