Only one IMRT plan (77301) can be billed per patient course of treatment, even if multiple plans exist as a result of boost plans,changes in field size, etc. However, if a new planning CT scan is acquired due to significant changes in patient or tumor anatomy, an additional IMRT plan may be appropriate if shown to be medically necessary. Sufficient documentation must exist if a new planning CT and IMRT plan is required.
The design and construction of the MLC device used for IMRT planning (77338) is billable once per IMRT plan. Even though IMRT plans contain multiple fields or arcs, the IMRT MLC is only billable as a quantity of one on the same date of service as the IMRT plan. However, additional units of the IMRT MLC may be billable for IMRT boost plans if approved and documented on different dates of service from the initial plan. The IMRT MLC should not be billed for compensator-based IMRT, where a complex treatment device (77334) is used to report the design and construction of the compensator.
Basic dosimetry calculations (77300) are billable with IMRT plans once for each static field or arc. If an IMRT field is too large for machine delivery and the carriage is split into additional fields, it is inappropriate to bill additional basic dosimetry calculations.
The number of basic dosimetry calculations (77300) does not differ based on the plan date of service. Since basic dosimetry calculations are billed once for each static field or arc, they are allowable if the boost plan is approved and documented on the same date of service as the initial plan or on a subsequent date of service. Whether or not an additional IMRT MLC (77338) is allowable depends on the approval and date of service of the boost plan. If approved and documented as a part of the initial plan, only a single IMRT MLC is billable. However, if the IMRT boost plan is approved and documented on a later date compared to the initial, an additional IMRT MLC along with all boost plan basic dosimetry calculations would be billable on the boost plan date of service.