Oncology & Hematology Coding Alert

Question: How many dosimetry calculations (77300) can we report a day?

California Subscriber

Answer: Most physician commercial carriers and Part B Medicare limit dosimetry calculations (77300, Basic radiation dosimetry calculation, central axis depth dose calculation, TDF, NSD, gap calculation, off axis factor ... as required during course of treatment, only when prescribed by the treating physician) to a maximum of six to eight a day for a typical session. For example, CIGNA Medicare states, "The typical course of radiation therapy will require from one to six dosimetry calculations, depending upon the complexity of the patient's problem."

However, treatments to the head, neck, prostate, or for Hodgkin's disease may require eight or more calculations, according to the American College of Radiology. If you want to report more than six calculations, you should provide supporting documentation of the calculations, which the physician must review, sign and date. Remember that hospitals do not have this limitation, because the OCE 15 (outpatient code editor) has no limits.