Russell J. Hamilton

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We report on the repositioning accuracy of patient setup achieved with a noninvasive head fixation device for stereotactic radiotherapy. A custom head mask which attaches to our stereotactic radiosurgery head ring assembly is fabricated for each patient. The position and orientation of a patient in the stereotatic space at the time of treatment are(More)
An essential step towards optimizing and automating radiation therapy treatment planning is to develop an effective algorithm to find the optimal beam weights and wedge filters for a given set of beam directions and modalities. This problem is solved by introducing a variable transformation based on the universal and omni wedge principles. Instead of(More)
This paper proposes a novel respiratory detection method based on diaphragm motion measurements using a 2D ultrasound unit. The proposed method extracts a respiratory signal from an automated analysis of the internal diaphragm motion during breathing. The respiratory signal may be used for gating. Ultrasound studies of diaphragm breathing motion were(More)
BACKGROUND/AIMS To identify physician selection factors in the treatment of locally advanced head and neck cancer and how treatment outcome is affected by Tumor Board recommendations. METHODS A retrospective analysis of 213 patients treated for locally advanced head and neck cancer in a single institution was performed. All treatments followed Tumor Board(More)
Quality of life is an important consideration in the treatment of early prostate cancer. Laboratory and clinical data suggest that higher radiation doses delivered to the bulb of penis and proximal penile structures correlates with higher rates of post-radiation impotence. The goal of this investigation was to determine if intensity-modulated radiation(More)
UNLABELLED The authors outline a method for three-dimensional registration of pelvic CT and 111In-labeled monoclonal antibody capromab pendetide (111In MoAb 7E11.C5) images using 99mTc-labeled red blood cell SPECT data. METHODS This method of CT-SPECT registration relies on the identification of major blood vessels in the CT and 99mTc SPECT images. The(More)
PURPOSE Preirradiation hormonal cytoreduction of prostate cancer has been proven to reduce exposure of normal structures by decreasing the size of the target volume. Dose-volume histogram (DVH) analysis, however, does not always appear to demonstrate a strong positive benefit with the use of neoadjuvant hormone therapy. This study analyzes various other(More)
Respiratory gating and tumor tracking for dynamic multileaf collimator delivery require accurate and real-time localization of the lung tumor position during treatment. Deriving tumor position from external surrogates such as abdominal surface motion may have large uncertainties due to the intra- and interfraction variations of the correlation between the(More)
PURPOSE We have developed and tested an interactive video system that utilizes image subtraction techniques to enable high precision patient repositioning using surface features. We report quantitative measurements of system performance characteristics. METHODS AND MATERIALS Video images can provide a high precision, low cost measure of patient position.(More)
A dynamic multi-leaf collimator (DMLC) can be used to track a moving target during radiotherapy. One of the major benefits for DMLC tumor tracking is that, in addition to the compensation for tumor translational motion, DMLC can also change the aperture shape to conform to a deforming tumor projection in the beam's eye view. This paper presents a method(More)