Home Past Events Archive Colloquium Colloquium: “Radiation Treatment Delivery Verification Using Cherenkov Light” — Thursday, March 31, 2022 at 4 PM

Colloquium: “Radiation Treatment Delivery Verification Using Cherenkov Light” — Thursday, March 31, 2022 at 4 PM

Dr. Paul J. Black, PhD, DABR and Dr. Michael T. Munley PhD, DABR
Department of Radiation Oncology
Wake Forest Baptist Medical Center
Wake Forest University
Thursday, March 31, 2022, 4 PM
George P. Williams, Jr. Lecture Hall, (Olin 101)
This will be an in-person and virtual event
To obtain the video conference link, contact wfuphys@wfu.edu

A reception will be held around the Olin Building Entrance at 3:30 PM prior to the colloquium. All interested persons are cordially invited to attend.


About half of all diagnosed cancer patients are treated using controlled exposures of ionizing radiation. In general, patients are given radiation delivered in a prescribed number of fractionated doses. As such, proper delivery of radiation therapy requires accurate patient positioning, to millimeters or even sub- millimeter accuracy. It is essential that positioning to be reproducible for each fraction delivery. This need for accurate and consistent patient positioning becomes even more important as the complexity or the fractional radiation dose increases. Conventionally, patient positioning is verified before radiation delivery, and immobilization devices are used to minimize patient movement after setup. An improvement on this methodology would be positioning verification performed in real-time, concurrent with treatment. Recently, groups have been working towards establishing methods for real time verification of radiation treatment delivery. One specific phenomenon that has been investigated for this purpose is Cherenkov light.

When highly energetic particles travel through matter, one of the emission products is optical light, through a process known as Cherenkov light emission. Cherenkov light is observable on patient skin during radiation treatment delivery. This type of light emission has been shown to correlate with ionizing radiation dose delivery in solid tissue, allowing real-time verification of radiation treatment delivery. We focused our study of Cherenkov light emission on the feasibility of radiation treatment field verification. Specifically, Cherenkov light images were acquired during radiation beam delivery to standard and anthropomorphic phantoms. Two clinical treatment scenarios were tested: 1) Observation of field overlaps or gaps in matched radiation fields and 2) Patient positioning shifts during modulated dose delivery.

The detectability limit for determining radiation field placement and phantom position was investigated. For matched fields, measurements of Cherenkov images agreed well with known matched field separations. Maximum discrepancies between known radiation field spacing and Cherenkov light images were on the order of 3-4 mm. In many cases, observed radiation field spacing exhibited discrepancies less than 1 mm. For the second portion of this study, detection of sub-millimeter positioning shifts was demonstrated. The major contributors to these discrepancies and detectability limits were radiation angle of incidence, beam energy, and radiation type. This study helps to establish detectability limits for this type of radiation treatment verification and identifies the parameters which introduce the largest amount of error in predicting radiation delivery accuracy using Cherenkov light images. This can be utilized in the development of Cherenkov light imaging as a real-time patient monitoring technique for clinical radiation dose delivery.


Mar 31 2022


4:00 pm - 5:00 pm


Olin 101
Olin Physical Laboratory, Wake Forest University, Winston-Salem, NC 27109


Jed Macosko