Solid Phantom Device for Beam Scanning


Project ID: D2021-29

Radiation therapy is a common curative procedure to treat cancer. The goal of radiation therapy is to expose the tumor to a sufficient dose of radiation so as to eradicate all cancer cells. The radiation dose is often close to the tolerance level of the normal body tissues. It is, therefore, necessary to determine the dosage levels in different parts of the irradiated body with high accuracy. Characterization of a radiation beam is a major part of acceptance testing and commissioning of complex linear accelerator units which are used for radiation treatment of cancer patients. Beam scanning using a computerized water phantom is widely used to conduct acceptance testing and commissioning of new x-ray producing linear accelerators, as well as for periodic quality assurance tests including the annual calibrations, and after any repair that may have affected the beam parameters. The golden standard in beam characterization in most clinics around the globe is to use a 3D beam scanning water phantom system. These units are expensive and involve very delicate pieces of equipment that need to be handled with extreme care. Moreover, they cannot be too far from the linear accelerator room as delivering the unit back and forth could also damage the system affecting the accuracy and resolution of the acquired data. Currently, no system other than computerized water scanning systems are available to answer all the clinical needs. This opens a new avenue to develop robust and improved systems for the accurate measurement of beam profiles.

Invention Description:

Researchers at the University of Toledo have developed a novel water-mimicking solid phantom device for beam scanning to replace the computerized 3D water scanning systems. The novel system is manufactured from solid water that contains arrays of detectors in a special geometrical shape and allows the measurement of beam profiles at any desired depth or direction for all the photon and electron beams. The entire assembly may be attached to the head of the gantry of a linear accelerator (LINAC), and may completely eliminate the need for computerized water scanning systems. After a few minutes of data acquisition, the user can extract profiles and percent depth dose data (PDD) within minutes and through software associated with the solid phantom reconstruct all the needed information to characterize the beam. This eliminates hours of water scanning setup and teardown, and a long wait for accurate data collection through slow movement of field ionization chamber inside the water tank. It also eliminates errors caused by potential wrong setups or driving of the scanning system.


Radiation therapy.


  • Replaces the 3D scanning water tank which is the main tool for acceptance testing and commissioning.
  • Significant reduction in cost.
  • Highly accurate dosimetry evaluation.
  • Small, lightweight, and easy to install at the head of the gantry.
  • Minutes of data collection compared to hours when using a water scanning system.
  • Minimum time spent for setup and teardown.
  • Fast reconstruction of data (obtaining PDD, profiles, or isodose distributions) to characterize the beam compared to using a conventional water scanning system.

IP Status: Patent Pending

Patent Information:
For Information, Contact:
Stephen Snider
AVP Tech Transfer
The University of Toledo
419 530 6225
E. Parsai
Diana Shvydka
Kanru Xie
3D scanning water tank
Acceptance testing
beam scanning
Radiation beam
Radiation therapy