Normally it is located under Tools\Accounts (you may need to first select 'View/change existing account') highlight you account and select 'Properties' or 'Change...' then select 'More Settings...' go to the Advanced tab and select 'Leave a copy of messages on the server' ..
To begin to create an opportunity for return on investment, the fees charged for cone beam scans can range anywhere from $250 to $600, depending on the facial region scanned, subsequent assessments performed, and who performs and interprets the scan.
External beam radiation costs anywhere from $100-200 per simple treatments and up to $400-700 for more complex typical treatments. Some very specialized procedures cost between $2000-5000 per treatment. Since most course of radiation require multiple weeks of daily treatments it can get very expensive.