77336
You should be able to bill the 77336 every five fractions regardless of type of therapy. The restriction with the 77301 is that you need to prove that the physicist actually did the weekly physics check above and beyond the check of the 77301. They cannot use the same physics check for both. As long as you are not billing them on the same date of service, you should be getting reimbursed for it.
As far as when to bill it, the key is to bill it every 5 fractions not just once weekly. A lot of physicists get in the habit of billing it out on the same day each week (i.e. every Tuesday). This will result in denials. Also, it is one of the few codes that does not actually need to be billed on the same date of service that it was performed. As long as it has been performed within the 5 fractions, you can bill it out of whichever date you want.
Example: Patient is treated for 5 fractions, Tuesday - Monday, Physicist checks the chart on Thursday, you can bill out the 77336 on any of those days. Just be consistent. Bill it out of fraction 5, 10, 15, etc. or one fraction 3, 8, 13, etc.
Also be aware that if you do any additional dosimetry on that date of service, you will need a modifier on the 77336.
Hope this Helps
Alanna M Stuart BS RT(R)(T), CPC, ROCC, CHONC