Division of Radiation Physics



Parham Alaei, Ph.D., Associate Professor, Director
Charles Conduah, M.S.
Patrick Higgins, Ph.D., Professor Emeritus 
Eric Ehler, Ph.D., Assistant Professor 
Susanta Hui, Ph.D., Associate Professor
Clara Ferreira, Ph.D., Assistant Professor 
Bruce Gerbi, Ph.D., Professor 
Jane Johnson, M.S., Instructor
Faiz Khan, Ph.D., Professor Emeritus 
David Sterling, M.S., Instructor
Yoichi Watanabe, Ph.D., Professor

Responsibilities of Physicists


  • Calibration of radiation generators and brachytherapy sources
  • Beam data acquisition
  • Patient dosimetry
  • Treatment planning
  • QA
  • Radiation protection


  • Beam characteristics
  • Radiation dosimetry - experimental and theoretical
  • Treatment planning models
  • Treatment technique development
  • Accuracy of treatment delivery
  • Imaging in radiotherapy

Treatment planning/Dosimetry

Treatment planning and dosimetry continues to be a major focus of research. Over the years departmental staff have developed manual and computerized dose calculation methods to accurately predict and deliver radiation dose to patients. The advent of CT and MRI has revolutionized the treatment planning process and we are currently engaged in developing computer algorithms for 3D treatment planning.

Special RT Techniques

TBI as a conditioning regimen for bone marrow transplantation has been used extensively at the University of Minnesota since 1974. We developed a high dose rate/bilateral TBI technique that has been adopted by many institutions in this country and abroad

We have also developed techniques for total skin electron therapy for the treatment of mycosis fungoides and other cutaneous lymphomas. These complex radiotherapy procedures required a considerable physics effort and ingenuity to make them routinely available for patients here and elsewhere

Recently we have begun offering IMRT (Intensity Modulated Radiotherapy), which requires specialized treatment planning and machine capabilities. The power of this therapy is to minimize dose to normal surrounding structures while maximizing dose to the tumor.

Other special RT techniques are: electron therapy, HDR, stereotactic radiosurgery (fractionated and single shot), brain implants, and biliary implants.

Electron Beam

This is a very useful treatment modality which has the characteristic of effectively treating superficial tumors but sparing deeper normal tissues. With our first linear accelerator installed in 1969, we participated in the pioneering development of electron beam therapy for treatment of the breast, skin, and head and neck cancers.

Interface Dosimetry

Passage of radiation beam through heterogeneous tissues (different density and atomic number) gives rise to varying amounts of dose absorption. At the interfaces such as lung-tissue, bone-tissue and air-tissue, regions of accentuated higher or lower dose may develop depending on beam energy and other treatment conditions. Our group has done extensive research on what is called the "transition zone dosimetry."