[eluser]smilie[/eluser]
I think (not sure tho') that you will have to serialize yourself.
However, I would suggest you to split that DB table into three fields (one for each checkbox).
I it easier to handle it that way (from code).
Let's say, in future - you only wish to get appointments for CT.
Then, you would (in PHP) have to get that serialized value out of 1 table field, unserialize it and then do preg_search on it to see if it matches your request.
If you have separate fields for each checkbox, you can simply do:
select ... from ... where ct = 1;
Cheers,
Smilie