Clinical Context
A typical patient is an adult newly diagnosed with a localized malignancy (for example, breast, lung, prostate, or head and neck cancer) referred to radiation oncology for planning of external beam radiation therapy. The patient presents to the radiation simulation suite on a scheduled day. Computed tomography (CT) simulation is performed with the patient positioned reproducibly using immobilization devices. The radiation oncologist and dosimetrist review imaging to determine the optimal size, number, and exact anatomic locations of treatment ports (field borders) or isocenters and any necessary patient markers or tattoos. When port placement requires fluoroscopic or other imaging correlation, a simulator or imaging modality is used to verify port coordinates relative to anatomic landmarks. The resulting port/field setup information is used to create the treatment plan and portals on the treatment machine and documented in the simulation and planning notes.
Typical workflow steps:
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Patient registration and consent.
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Immobilization and CT simulation (with or without contrast) while in treatment position.
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Acquisition of simulation images and, when indicated, use of an on-board simulator or fluoroscopy to localize and mark port sites.
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Attending radiation oncologist documents port size, shape, location, and any blocking or beam-modifying devices.
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Transmission of simulation data to dosimetry for treatment planning, and scheduling of subsequent treatment delivery sessions.
Coding Specifications
| Modifier | Description | When to Use |
|---|
25 | Significant, separately identifiable evaluation and management service by the same physician on the day of a procedure | Use when a separate E/M visit is performed and documented the same day as simulation/port placement. |
| 26 | Professional component | Use when billing only the physician's interpretation/planning component separate from technical services.
| 52 | Reduced services | Use when the simulation/port determination is partially reduced or abbreviated.
| 53 | Discontinued procedure | Use when simulation/port determination is started but discontinued due to patient condition or other unforeseen events.
| 59 (not listed in raw modifiers) | Data not available in the input. |
| 62 | Two surgeons | Use rarely when two physicians of the same specialty collaborate on complex simulation decisions (applicable when recognized by payer).
| 78 | Unplanned return to the operating/procedure room by the same physician following initial procedure for a related procedure during the postoperative period | Use if an unplanned repeat simulator procedure is required emergently; verification with payor policy recommended.
| 80 | Assistant at surgery | Use when an assistant participates in a procedure that allows assistant billing and payer accepts for simulation procedures.
| 81 | Minimum assistant at surgery | Use when a minimal assistant is documented and allowed by payer for the service.
| 82 | Assistant not available | Use when a qualified resident or assistant is not available and the service documentation supports this modifier.
| TC | Technical component | Use when billing or separating the technical component of the simulation (imaging acquisition, equipment use) from the physician component.
| QK | Medical direction of two, three, or four qualified individuals | Use when the physician medically directs multiple non-physician personnel performing aspects of simulation under supervision.
| QX | CRNA service with medical direction by a physician | Use if anesthesia services are involved during simulation and billed with modifier applicability under payer rules.
| AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for Medicare beneficiaries | Use when an APP provides the simulation service and payer allows billing under AS.
| Taxonomy Code | Specialty | Notes |
|---|
207RC0000X | Radiation Oncology | Primary specialty responsible for simulation and port determination. |
| 207RH0000X | Radiation Therapist | Performs CT simulation scans and delivers technical components; works under radiation oncologist direction.
| 208000000X | Diagnostic Radiology | May perform or assist in imaging-guided localization when advanced imaging is required.
| 363LP0800X | Medical Dosimetrist | Plans beam arrangements and converts port/field locations into treatment plans (non-billing taxonomy often associated).
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|
C50.911 | Malignant neoplasm of unspecified site of right female breast | Common indication for external beam radiation requiring port/field localization. |
| C34.90 | Malignant neoplasm of unspecified part of bronchus or lung, unspecified side | Lung cancers frequently require simulation to determine field placement and block margins.
| C61 | Malignant neoplasm of prostate | Prostate radiotherapy uses simulation to localize portals and immobilization for precise delivery.
| C32.9 | Malignant neoplasm of larynx, unspecified | Head and neck cancers require careful port placement to spare critical structures.
| C79.51 | Secondary malignant neoplasm of bone | Palliation of bone metastases commonly uses simulation to determine treatment ports for symptomatic relief.
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|
77295 | Therapeutic radiology simulation-aided field settings, complex | Often performed when the simulation requires complex field arrangements; may be billed for complex simulations following initial port localization. |
| 77261 | Therapeutic radiology simulation, simple | Represents simpler simulation setups; may be used for straightforward port/field determinations when less complexity is documented.
| 77301 | Radiation treatment delivery, simple; per day | Represents daily treatment delivery codes that follow simulation/port determination once the treatment plan is complete.
| 77370 | Special radiation physics consultation, or complex physics consultation | Used when advanced physics input is required after port determination to finalize machine settings or special beam modifications.
| 77290 | Therapeutic radiology portal/field and/or block verification; simple | Used for verification films or images that confirm port/field placement prior to or during the course of treatment.
| 77014 | CT guidance for localization during therapeutic procedures | May be used when CT guidance is separately reported for localization during simulation if payer policy permits.