Pediatric radiotherapy requires optimal immobilization and is often complicated by the need for daily general anesthesia. To decrease anesthesia use, we implemented a novel Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) system, allowing children to watch video during treatment. We investigated its effectiveness on reducing anesthesia usage, cost, and time in pediatric radiotherapy, and analyzed its impact on dose delivery. AVATAR utilizes a digital media player which projects video onto a carbon-fiber radiolucent screen within the patient's line of vision. We performed a 3 year retrospective institutional analysis on 75 children, ages 4-10, who received radiotherapy (all children 0-3 required anesthesia, and only 1 >10, so were excluded). We compared frequency of anesthesia use 1.5 years prior to AVATAR with the 1.5 years after implementation. The number of anesthesia treatments spared was used for a cost analysis using cost to payer data. Children who started with anesthesia, then transitioned to AVATAR, were used to compare treatment time between the 2 methods. Additionally, a radiation course was delivered to a phantom, and dose to skin measured with optically stimulated luminescent dosimeters (OSLDs) both with and without the AVATAR system. Of the 75 children, the median age prior to AVATAR was 7 (n =35) and with AVATAR was 6 (n=40). With AVATAR, only 4 of 40 children (10%) required anesthesia to complete their course of radiation, compared to 37% previously, thus a 27% absolute reduction in anesthesia use. Six children required anesthesia initially, but transitioned off within 2-7 fractions using AVATAR. Analysis of treatment time demonstrated an average reduction of 13.3 minutes per session (35.4 minutes with anesthesia versus 22.1 minutes with AVATAR), a 37% reduction, not accounting for additional time saved in pre- and post-anesthesia care units. Previous studies document a 6 week course of anesthesia for radiation treatment costs $50,000 in payer charges, or $1,666 per treatment. In the last 1.5 years, 603 treatment sessions of anesthesia were replaced by AVATAR, a cost savings of $1,005,000. To document possible changes in dose delivery from the AVATAR, a craniospinal course was delivered to a phantom. Using OSLD measurements, we found a small increase in skin dose of 0.8%-9.5% with AVATAR. In comparison, use of a thermoplastic face mask increases skin dose up to 58%. For children undergoing radiotherapy, AVATAR resulted in a 27% reduction in anesthesia use, a 37% reduction in time per session, and estimated cost savings of >$1,000,000 over 1.5 years -- all with minimal dose effect, and avoiding potential risks associated with anesthesia. These reductions are invaluable to children undergoing radiotherapy, and support continued clinical development of the AVATAR system.