Background: The COVID-19 pandemic resulted in the use of telemedicine for evaluation and management visits in radiation oncology departments to decrease in-person interactions. The primary objective of this study is to evaluate the utility of telemedicine for patient consultation and its effect on radiotherapy simulation and treatment processes. Methods: A standardized simulation requisition directive was used for all consults (telemedicine and in-person) undergoing simulation for external beam radiation therapy at a single tertiary care institution from January to December 2020. These directives were reviewed at daily multi-disciplinary peer review meetings; modifications occurring as a result of this review were prospectively recorded in a departmental quality database. Descriptive statistics were used to identify characteristics associated with consultation type. Mann Whitney and Chi-square tests were used to compare continuous and categorical variables. Results: 1500 consecutive patients were reviewed in this prospective peer review process; 444 (29.6%) had telemedicine visits preceding simulation and 1056 (70.4%) had in-person consults. The median time between physician simulation order and date of simulation was 5 days (IQR: 2-11 days) for telemedicine visits and 4 days (IQR: 1-8 days) for in-person consults (p<0.05). Significant differences were observed in telemedicine usage across months (p<0.05) with the highest percentage in July, September, and August (50%, 45.9% and 45%, respectively). As a result of prospective multidisciplinary peer review, 397 modifications in 290 simulations were recorded in total; 101/444 (22.7%) telemedicine simulations had modifications compared to 189/1056 (17.9%) following in-person consultation (p<0.05). The most common modifications for telemedicine visits resulted from immobilization device changes (n=32, 23.5%), arm positioning (n=19, 14.0%), and changes in the radiotherapy care path (n=17, 12.5%). For telemedicine consults, the median radiotherapy fraction dose was 2.66 Gy (2-4 Gy) and median fraction number was 16 (5-28). There was no difference for fractionation preference between telemedicine and in person consults (p=0.084). Seven (1.6%) telemedicine visits and 7 (0.7%) in-person consults needed re-simulation during the entire study period (p=0.136). Conclusions: Telemedicine is a powerful tool with the potential to revolutionize the radiation oncology daily practice. In the initial learning phase, it appears that there is a higher frequency of simulation modifications for patients evaluated by telemedicine. Therefore, as departmental processes incorporate telemedicine in the future, thorough attention is needed to encourage review of common modifications as well as identify patients at high risk of error at time of simulation who may also benefit from in-person evaluation prior to simulation.