Intensity-modulated Radiotherapy: Medical physicists at Mary Bird Perkins Cancer Center are studying the fundamentals and clinical potential of using intensity modulated x-ray therapy (IMXT) in lieu of or in conjunction with modulated electron therapy (MET). This research is being done by Dr. Hogstrom as part of a research agreement with TomoTherapy, Inc. Parallel to this work, applications of an electron multi-leaf collimator (eMLC) to MET are being studied and compared to utilization of compensating wax bolus to achieve energy modulation. This research is being done by Dr. Hogstrom as part of a research agreement with Varian Medical Systems, Inc.
Image-guided Radiotherapy: Drs. Hogstrom, Gibbons, and Parker at Mary Bird Perkins Cancer Center are conducting research in image-guided radiation therapy physics, gated radiotherapy, and adaptive radiotherapy. One research program concentrates on usage of orthogonal x-ray imaging using the BrainLab Novalis for radiosurgery and radiotherapy of brain and extra-cranial cancers, e.g. spine, liver, and prostate. Another program focuses on usage of megavoltge CT scanning using the TomoTherapy HiART for radiotherapy of prostate, head and neck, and many other anatomical sites. These programs are currently supported by research agreements with BrainLAB, Inc. and TomoTherapy, Inc. respectively.
X-ray Capture Therapy: X-ray capture therapy is a potentially new radiotherapy paradigm (chemo-irradiation) that uses monochromatic x-rays to deliver targeted radiation dose to high-Z labeled (e.g. iodine) pharmaceuticals that are preferentially taken up by cancer cells, e.g. IUdR taken up by DNA. Our research program, led by Drs. Hogstrom, Sajo, and Varnes, uses the CAMD synchrotron’s monochromatic x-ray beam line to study dosimetry techniques, treatment planning dose algorithms, microdosimetry, cell biology, and small animal irradiations. Our long term goal is to conduct clinical trials using a prototype laser-particle accelerator (mxisystems.com) to produce monochromatic x-rays such as one developed by mixisystems.com.
Prostate Brachytherapy Dosimetry: Faculty members have recently received a US Patent on a proposed new method for the direct dosimetry of permanent interstitial prostate implants (seeds). Traditional prostate dosimetry entails the tedious and error-prone task of identifying and locating the implanted radioactive seeds on anatomical images following treatment. The new method allows direct determination of the dose distribution without the intermediate step of explicitly finding the seeds. Thus, both the accuracy and required time in mapping the dose should be improved. Dr. Sajo and Dr. Matthews are presently researching this proposed method.
Radioisotope Imaging Systems: Dr. Matthews is pursuing research in radioisotope imaging. Radioisotope imaging uses radioactive materials injected into a patient or subject to evaluate physiological function. Positron emission tomography (PET) and single-photon imaging are common methods for radioisotope imaging. Current projects include:
- development of hand-held CZT detector systems for intraoperative imaging;
- development and performance characterization of a compact CZT-based gamma camera;
- development of a modified gamma camera design to facilitate coincidence imaging of PET radiotracers;
- observer performance study to evaluate acquisition protocols for commercial clinical PET/CT systems;
- methods for performance assessment and quality assurance of PET/CT imaging systems.
Intravascular Radioisotope Imaging: Drs. Shikhaliev and Matthews are developing methods for intravascular imaging of radiopharmaceuticals (e.g., 18F-fluorodeoxyglucose). This approach utilizes storage phosphor detectors mounted on the end of a catheter to detect radiotracer uptake in vulnerable plaques in coronary arteries. [Phys. Med. Biol. 51: 963-979 (2006)].
X-ray Imaging Detectors: A current project is the development of photon counting detectors for x-ray imaging and computed tomography (CT). The use of CZT detectors, tilted relative to the x-ray beam, facilitates both photon counting and energy weighting. Energy weighting allows a reduction of scattered radiation and good dose efficiency for imaging. [Phys. Med. Biol. 51: 4267-4287 (2006)].
Radiation Damage in DNA: Dr. Sajo conducts fundamental research in radiation biology in cooperation with faculty members in the Department of Physics and Astronomy and the Department of Biological Sciences to quantify genetic effects of high versus low linear energy transfer (LET) radiation by examining interaction physics at the DNA molecular level. This work may help researchers to understand more clearly the damage mechanism of radiative energy deposition in human tissue, and thus the relationship between radiation exposure and disease formation. A major grant proposal has been submitted to NASA to investigate the mutation spectrum caused by galactic radiation of extremely high energy and high mass particles. This research will facilitate the assessment of the risks of prolonged manned missions in outer space.
Aerosol Transport: The US Department of Energy (DOE) is funding an experimental and numerical modeling study aimed at understanding how aerosolized particles disperse in enclosed environments. This work, directed by Dr. Sajo, may be used to predict the behavior of radioactive or other hazardous materials in indoor environments following accidental releases, and can also be applied to analyzing terrorism threats from bacterial and germ warfare agents. In addition, the work provides a better understanding of how aerosols travel in human airways. A major application of this research would be improving ways to deliver aerosol medications.
Radiation Detectors for Medical Physics, Health Physics and Security Applications: Faculty and graduate students are developing novel instruments and methods for radiation detection applications in radiation protection, dosimetry, and nuclear security.
