A program is proposed to investigate the feasibility of a new ultra-small wireless in vivo dosimeter concept that could have the potential to enable entirely new approaches to radiation cancer therapy. The enabling technology is a radiation-sensitive variable capacitor (varactor) based upon fully-depleted silicon-on-insulator (FDSOI) semiconductor technology, a platform that provides an ideal mechanism for transducing radiation-generated charge into an electromagnetic frequency shift that can be detected using wireless telemetry. For radiation therapy, verification of both the delivered dose and the location where it is delivered is critical for successful treatment. (This is particularly important for cliical situations where delivered dose is not well understood or modeled. These include cervix cancers;targets that move significantly during a treatment session, such as those located in the lung;and tumors located near sensitive structures such the vertebral column or the optic nerve. The detectors could also be extremely useful in proton therapy.) Wireless dosimeters for in vivo use have been developed previously, but these dosimeters are too large for routine use. The extremely small sizes of the FDSOI dosimeters (fully packaged parts could have volumes on the order of 1 mm3) could allow both dose and position information to be obtained from precise locations using a minimally invasive procedure. In addition, the small size and ability to tune to the devices to different resonant frequencies allows multiple sensors to be placed. In order to realize this goal, a research program has been developed to assess the feasibility of this concept. A design study for FDSOI varactors is proposed to determine the structural parameters that will allow the best trade-off between capacitance tuning range and quality factor, the two main parameters that ultimately affect the sensitivity of the dosimeter. The devices will be fabricated at the University of Minnesota and their basic characteristics will be measured. Finally, the devices will be characterized under clinically relevant irradiation conditions. The research team consists of an electrical engineering professor, a radiation therapy medical physicist, (and an oncologist clinician) who have precisely the right mix of expertise to design and fabricate the devices and to evaluate their suitability to meet the requirements for use in cancer therapy.

Public Health Relevance

The project seeks to improve public health by developing a technology that could substantially improve the outcome of radiation therapy treatments. Radiation therapy is a pure targeting endeavor whose primary goal is to deliver the maximum dose to a cancerous tumor while minimizing the dose to surrounding sensitive tissue. As radiation therapy treatments become increasingly complex, the technology developed in this program could ensure that future radiation therapies are more effective at killing cancer cells, while minimizing adverse side effects from this treatment protocol.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21CA169759-01A1
Application #
8581751
Study Section
Special Emphasis Panel (ZCA1-RTRB-Z (M1))
Program Officer
Capala, Jacek
Project Start
2013-07-01
Project End
2015-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
1
Fiscal Year
2013
Total Cost
$179,287
Indirect Cost
$48,787
Name
University of Minnesota Twin Cities
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455