Stacked Pie Cage In Vivo Mouse Dosimetry Involving Multiple Sources and Energies

The study measures the dose for phantom mice within three stackable pie cages, using all of the most common irradiation devices used in radiobiology today. It facilitates determination of net scatter factors for irradiation caused by the cages and mice being in the beam, at energies ranging from 160 keV to 15 MV. In vivo radiation measurements using TLDs on phantom mice were used to approximate the dose at each pie cage stack level. Irradiation devices include a particle accelerator at 6, 10 and 15 MV, cobalt unit at 1.253 MeV, cesium unit at 662 keV, and a standard x-ray unit at 160 keV. Energy dependence was observed with respect to the dose given. Dose change irregularities were consequentially a result of attenuation and scatter throughout the pie cage. This dose dependence on energy was found to increase with increasing photon energy. Dose results from stacked cage irradiation were found to be within SF=0.701-2.508 (-30% to +251%) of the calibrated dose output. Radiation measurements suggest considerable dosimetric differences exist to mice at each level when pie cages are stacked. Results varied remarkably when also including a change in the incident photon energy beam. Researchers may make use of plots offered in this research to estimate corrections to the calculated irradiation time needed to arrive at the prescribed radiation dose to mice at any level. Data provided directly correlate to the dose given to real mice at any energy using this same geometry.