Shape matrix decomposition is a subproblem in radiation therapy planning. A given fluence matrix A has to be written as a sum of shape matrices corresponding to homogeneous fields that can be shaped by a multileaf collimator (MLC). We solve the problem to find an approximation B of A satisfying prescribed upper and lower bounds for each entry. The approximation B is determined such that the cor...

In this paper, the efficiency and uniformity improvement of non-image LED illumination system with collimator, microlens array and condenser are proposed for pico-projector. The LED light is collimated to 18 degree with efficiency 99.36% by collimator. For image uniformity and flux efficiency, the doule-side microlens array and two condensers are adopted to form a homogenizer. With this homogen...

An imaging displacement sensor (IDS) has been developed that can measure the displacement with an accuracy of 30 nm in 0.03 s with the precision improving to 1 nm for averaging times of 100 s. The IDS consists simply of a light emitting diode (LED) pinhole collimator and a charge-coupled device (CCD) camera chip. The position accuracy is better than 0.05% over the few mm CCD size with deviation...

Based on a correlation analysis method, a subwaveform threshold retracker is developed and coded in FORTRAN for satellite altimetry to determine the leading edge and retracking gate, and to improve the precision of sea surface heights (SSHs) and gravity anomalies (GAs). Using ERS-1/ERM waveforms, the subwaveform threshold retracker outperforms full-waveform threshold retrackers at the tide gage...

We introduce a dynamic and secondary-memory-based variant of the List of Clusters, which is shown to be competitive with the literature, especially on higher-dimensional spaces, where it outperforms the M-tree in searches and I/Os used for insertions. The basic principles of our design are applicable to other secondary-memory structures.

An integrated imaging sensor system is being developed to enhance operations of robots and telerobotic systems used in nuclear industry . This system combines a gamma ray image of the distribution of radioactivity with a video image of the area, allowing a rapid and intuitive determination of the source location . The gamma ray imaging system is based upon a position sensitive photomultiplier t...

BACKGROUND Stereotactic radiosurgery/radiotherapy procedures are known to deliver a very high dose per fraction, and thus, the corresponding peripheral dose could be a limiting factor for the long term surviving patients. The aim of this clinical study was to measure the peripheral dose delivered to patients undergoing intracranial Cyberknife treatment, using the MOSFET dosimeters. The influenc...

UNLABELLED The Inveon small-animal SPECT system comes with several types of multipinhole collimator plates. We evaluate here the performance measurements of the Inveon SPECT system using 6 different collimators: 3 dedicated for mouse imaging and 3 for rat imaging. METHODS The measured performance parameters include the sensitivity, the spatial resolution using line sources, the ultra-micro De...