2025 CPT code 77331
(Active) Effective Date: N/A Revision Date: N/A Radiology - Dosimetry Radiology Procedures > Radiation Oncology Treatment Feed
Special dosimetry (e.g., TLD, microdosimetry), performed only when prescribed by the treating physician.
Modifier 26 (professional component) may be appended if only the professional interpretation is billed. Modifier TC (technical component) may be appended if only the technical aspect of dosimetry is billed; however, payer policies may vary.
Special dosimetry is medically necessary when the complexity of the patient's anatomy or treatment plan requires precise verification of dose delivery.This is crucial for optimizing treatment effectiveness and minimizing potential side effects. Medical necessity is supported by the physician's order and clinical documentation.
The radiation oncologist or medical physicist is responsible for ordering and interpreting the results of special dosimetry. The medical dosimetrist performs the measurements and calculations.
In simple words: This medical code describes a special test to measure the exact amount of radiation a patient receives during cancer treatment. It uses special tools to make sure the radiation is delivered correctly to the tumor, while protecting healthy parts of the body. The doctor must order this test.
This CPT code, 77331, encompasses special dosimetry procedures in radiation oncology.It involves the precise calculation and measurement of radiation doses delivered to a target area within the patient's body. This is done under specific circumstances, requiring explicit physician orders. The procedure utilizes specialized equipment like thermoluminescent dosimeters (TLDs) and dosimetry probes to measure radiation doses.The results are used to validate or adjust the existing radiation treatment plan, ensuring optimal radiation delivery and minimizing potential harm to healthy tissues. Microdosimetry, measuring the effects of very small radiation amounts, may also be included under this code.
Example 1: A patient undergoing intensity-modulated radiation therapy (IMRT) for prostate cancer requires special dosimetry to verify the accuracy of the treatment plan and ensure the prescribed dose is delivered precisely to the target area while minimizing exposure to surrounding organs., A patient receiving brachytherapy for cervical cancer requires microdosimetry to assess the radiation dose distribution at the microscopic level within the tumor and surrounding tissues., A patient with a complex anatomical structure requiring highly conformal radiation therapy needs special dosimetry to optimize the treatment plan by adjusting beam arrangements and dose distributions.
Physician's order specifying the need for special dosimetry; detailed treatment plan outlining the target area, prescribed dose, and treatment technique; results of dosimetry measurements, including specific equipment used and calculation methods; any adjustments made to the treatment plan based on dosimetry results;patient's medical history relevant to radiation therapy, including previous treatments and imaging studies.
** This code is used only for special dosimetry procedures ordered by the physician. Routine dosimetry is generally included in other radiation therapy codes.
- Revenue Code: P7A (ONCOLOGY - RADIATION THERAPY)
- Payment Status: Active
- Modifier TC rule: Modifier TC may apply if billing for the technical component only.The use of modifier TC depends on payer-specific policies and whether the provider is a hospital or a private practice.
- Specialties:Radiation Oncology, Medical Physics
- Place of Service:Inpatient Hospital, Outpatient Hospital, Ambulatory Surgical Center