Encrypted login | home

Program Information

The Evaluation of Dosimetric and Cancer Viability Difference Following In Vitro Irradiation

no image available
B Rogers

B Rogers1* , E Ehler1 , J Lawrence2 , C Ferreira1 , (1) University of Minnesota, Minneapolis, MN, (2) University of Minnesota, St. Paul, Minnesota


SU-I-GPD-T-646 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: Clonogenic and cell viability assays in cancer research are well described, however, the methodology in which radiation is delivered is often incompletely described. There is a clear need to standardize the method by which cells are irradiated during in vitro studies to permit comparisons between studies and to ensure accuracy of reporting. The purpose of this study is to determine the dose accuracy of a series of methods of in vitro irradiation.

Methods: A 3D printed insert was constructed for the bottom side of a 96-well flat bottom plate. Using EBT3 film placed directly beneath a 96-well plate with the well bottoms placed at depths of 2.3cm and 10cm in Gammex Solid Water, measurements were obtained using 20x20cm2, 30x30cm2, and 40x40cm2 field sizes. Irradiations were performed at 100cm SSD with 6MV photons using a Varian TrueBeam linear accelerator. Film measurements were obtained “in-air” with the insert included and excluded; and with the plate submerged in water to remove air gaps. The film region of interest was defined as the areas located directly below the four central wells at the time of irradiation. For each depth, the “in-air” measurement was compared with the result of the “in-water” measurement.

Results: Doses measured at depths of 2.3cm and 10cm indicate a weak dependence on the presence or absence of small air gaps within the 96-well plate at the time of irradiation. The maximum deviation from the in-water measurements was approximately 2%. Minimal deviation occurred with field sizes of 30x30cm2 and 20x20cm2 for the d=2.3cm measurements and d=10cm measurements, respectively.

Conclusion: This study indicates a maximum dose perturbation of 2% below a single 96-well plate. Additionally, there is a dependence on field size. Use of the 3D printed insert yielded minimal change. These data provide an initial reference to standardize in vitro radiation.

Contact Email: