SU-E-T-262: Treatment Room Activation after 15 MV Single Fraction Radiation Treatments Delivered Using Varian's TrueBeam and Trilogy Linear Accelerators.

PURPOSE: To measure radiation levels in treatment room due to activation after 15MV single fraction radiation treatment (SFRT) delivered to a solid water phantom. METHODS: We performed radiation surveys of two LINAC treatment rooms immediately after 15 MV SFRT. We delivered a sequence of two 15 MV single fraction IMRT treatments to a phantom at the end of a typical treatment day. The first treatment delivered was 6201MU (about 12 Gy) and the second one, 15 minutes later was 12711 MU (24 Gy). Both were delivered to the pelvic region of a solid water anthropomorphic phantom. In a second technique, a 15 MV VMAT SFRT (4326 MU) was delivered using the Varian TrueBeam LINAC. Radiation measurements were recorded repetitively at four locations using a thin windowed Geiger Muller detector, a sodium iodide photon spectrometer and a pressurized ionization chamber. The four locations surveyed were: the top of the collimator head, the collimator window surface, the isocenter, and the inferior end of the patient support assembly. RESULTS: Radiation levels at the isocenter at the end of the treatment day and before the two IMRT SFRTs varied from 0.06 to 0.1 mR/h. Within 2-3 minutes after finishing the second IMRT SFRT the radiation levels were approximately 10 and 1.4 mR/h at isocenter for the TrueBeam and Trilogy rooms respectively and around 0.6 mR/h for the TrueBeam VMAT SFRT. Closing the MLC and the jaws significantly reduces the radiation level at isocenter. The average half life of the mixture of radionuclides produced is about 10 minutes. CONCLUSIONS: High dose single fraction IMRT treatments with 15 MV photons produce elevated treatment room activation as compared to conventional IMRT. In addition, activation levels varied between the TrueBeam and Trilogy for similar SFRT schemes. There is no funding support, disclosures, or conflict of interest.

[Comparative safety study of two commercialised vaccines against canine babesiosis induced by Babesia canis]. / Etude comparative de l'innocuité de deux vaccins commerciaux contre la babésiose canine provoquée par Babesia canis.

The safety of two vaccines available on the French market against canine babesiosis - Nobivac Piro® (NP) and Pirodog® (P) - have been evaluated. Their local, general and biochemical impacts have been compared in a controlled experimental study. Three groups were used: a control group (T) and two groups vaccinated twice at 21 days interval. All dogs presented moderate local reaction. However, either clinical and biological parameters showed that the NP group presented a significantly more intense reaction at the injection site compared to the P group. No statistical difference has been revealed between the groups P and T evolutions.

The measurement of ground reaction force in dogs trotting on a treadmill: an investigation of habituation.

We studied the time necessary to obtain reliable kinetic data from healthy dogs trotting on a treadmill. Ten adult male Malinois Belgian Shepherd dogs were made to trot on an instrumented treadmill to record the ground reaction force for the entire body and to determine the vertical force variables (peak [PFz], impulse [IFz], stride time [Str], peak time [Tz] and contact time [Ct]). Data were collected from each dog, during three sequences per day, on three consecutive days. In order to determine the contribution of the sequence, day of measurement, and dog factors and the percentage of variance attributable to dogs, data were analyzed with a linear mixed model. The curve shapes were similar to those obtained with a floor-mounted force platform. Intra-dog coefficients of variation were between 1.57 and 3.46%. Inter-dog coefficients of variation were between 4.18 and 7.82%. A sequence effect was not noted. Each day had a significant effect on all of the data. All variables differed significantly from the first day compared to the other days. However there was not any difference between days 2 and 3. The percentage of the total variance attributable to dogs ranged from 37 to 88%. The coefficients of variation were lower than those obtained with common protocols. The treadmill locomotion remained consistent during a single session. Even if interday variation needs to be accounted for, reliable data can still be obtained after a single training session. The majority of the variation was attributable to the dog. An instrumented treadmill may be used for kinetic analysis.