2025 CPT code 77300
(Active) Effective Date: N/A Revision Date: N/A Radiology - Radiation Oncology Dosimetry Radiology Procedures > Radiation Oncology Treatment Feed
Basic radiation dosimetry calculation, including factors like central axis depth dose, TDF, NSD, gap calculation, off-axis factor, and tissue inhomogeneity factors, as needed during treatment, only when prescribed.
Modifiers 26 (professional component), 52 (reduced services), 59 (distinct procedural service), and 76 (repeat procedure) might be applicable depending on circumstances.
Medical necessity for 77300 is established when a radiation oncologist orders a basic dosimetry calculation as part of a comprehensive radiation treatment plan.It is essential for ensuring safe and effective radiation delivery to the target while minimizing damage to healthy tissues. Changes in patient weight, tumor size, or treatment response might warrant additional calculations.
The radiation oncologist is responsible for prescribing and interpreting the dosimetry calculations.Medical physicists usually perform the calculations, but the oncologist reviews and approves them.
In simple words: This code covers the calculations to determine the right amount of radiation for cancer treatment.It involves figuring out the best way to deliver the radiation to the tumor, taking into account many factors to keep healthy tissue safe.These calculations are done as needed during the treatment.
This CPT code encompasses the basic radiation dosimetry calculation required during a course of radiation therapy.The calculation considers several factors, including central axis depth dose, time-dose factor (TDF), nominal standard dose (NSD), gap calculation, off-axis factor, and tissue inhomogeneity factors.It's performed as needed throughout the treatment, based on the physician's prescription and changes in patient status (e.g., weight changes).
Example 1: A patient with lung cancer is undergoing external beam radiation therapy.The radiation oncologist orders a basic dosimetry calculation (77300) at the start of treatment to determine the optimal radiation dose and plan.Subsequent dosimetry calculations may be ordered during the course of treatment if there are significant changes in the patient's weight, tumor size, or response to treatment., A patient with prostate cancer is receiving brachytherapy.A basic dosimetry calculation (77300) is performed to determine the optimal dose and placement of radioactive seeds. This may be repeated if there are unexpected changes during the treatment., A patient with head and neck cancer is undergoing intensity-modulated radiation therapy (IMRT).The initial treatment plan requires a basic dosimetry calculation (77300).During the course of treatment, adjustments might be needed due to changes in the patient's anatomy, and additional 77300 calculations may be necessary.
* Physician's order for dosimetry calculation.* Patient's medical history and imaging studies (CT, MRI, etc.).* Tumor delineation and target volume definition.* Treatment plan specifics (e.g., radiation modality, fractionation scheme).* Details of the dosimetry calculation itself (including all relevant factors).* Physician's review and approval of the dosimetry calculation.
** If only an electron calculation is performed instead of an electron isodose plan, report 77300 and not 77321.
- Revenue Code: P7A (ONCOLOGY - RADIATION THERAPY)
- RVU: The RVUs for this code vary based on geographic location and other factors; consult your local Medicare Administrative Contractor (MAC) for specific values.
- Global Days: Not applicable. This is a separately reported procedure.
- Payment Status: Active
- Modifier TC rule: Modifier TC (Technical Component) is not applicable to this code.This is a professional service.
- Fee Schedule: Historical fee schedule data is not available in this source. Consult your local MAC for historical fee schedule data.
- Specialties:Radiation Oncology
- Place of Service:Office, Outpatient Hospital, Ambulatory Surgical Center