Ed G Shapiro

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PURPOSE To develop an image receptor capable of forming high-quality megavoltage CT images using modest radiation doses. METHODS AND MATERIALS A flat-panel imaging system consisting of a conventional flat-panel sensor attached to a thick CsI scintillator has been fabricated. The scintillator consists of individual CsI crystals 8 mm thick by 0.38 mm x(More)
Current electronic portal imaging devices (EPID) are limited in their ability to provide direct and quick verification and monitoring of patients during both setup and treatment of breathing synchronized radiotherapy (BSRT, including breathing gated, voluntary and forced breath-hold radiotherapy treatment.) These limitations are largely due to their slow(More)
Thermal dosimetry studies of the Helios ultrasound system were performed in a tissue-equivalent phantom and in porcine tissues in vivo. SAR distributions in the phantom demonstrate the adjustability of the power deposition pattern from the 50 cm diameter annular array of 30 transducers. Examples are given of well-localized SAR patterns (< 3 cm diameter) in(More)
Initial heating rates (degrees C/min) along parallel tracks at depths of 1-14 cm in a static, muscle-like phantom were determined from time-temperature profiles obtained with 'Helios', a 30-beam ultrasonic hyperthermia system developed by Varian Associates. Data were taken at a single operating frequency of 556 kHz, for different sets of focal plane ring(More)
For a system of interacting fundamental and second harmonics the soliton family is characterized by two independent parameters, a soliton potential and a soliton velocity. It is shown that this system, in the general situation, is not Galilean invariant. As a result, the family of movable solitons cannot be obtained from the rest soliton solution by(More)
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