CPT 77290 in Medical Billing: Simple, Intermediate and Complex Simulation, Plus the 77293 Add-On

CPT 77290 is the complex level of therapeutic radiology simulation-aided field setting: positioning and immobilizing the patient and acquiring the images that define the treatment portals, when three or more treatment areas are involved or when the case uses arc therapy, particle therapy, complex blocking, custom shielding, brachytherapy, hyperthermia probes or contrast. The related codes are 77280 (simple) and 77285 (intermediate), and 77293 is the respiratory motion management add-on.

Most practices code the first simulation correctly. Errors are more common with the second one, and with IMRT, where no simulation code is billed at all. The full rules are below.

Where you see it

Place	What goes there
CMS-1500 box 24D	77280, 77285 or 77290, one unit, global in a freestanding center or with 26 in a hospital; 77293 on its own line with the same modifier pattern
837P electronic claim	Loop 2400, SV1: 77290, modifier 26 or TC when the components are billed separately, unit count 1
Medicare Physician Fee Schedule (RVU26D)	PC/TC indicator 1 (splits into 26 and TC) for all four codes; global period XXX for 77280 to 77290, ZZZ (add-on) for 77293
Medicare MUE table (October 1, 2026)	77280: 2 per day; 77285, 77290 and 77293: 1 per day
Hospital outpatient claim (OPPS Addendum B, 2026)	77280 in APC 5611; 77285 and 77290 in APC 5612; 77293 status N (packaged, no separate payment)
Treatment planning system	The simulation note, immobilization devices and image sets that support every unit

The three levels

Code	Level	What qualifies	2026 RVUs (national)
77280	Simple	One treatment area, or a verification simulation of any number of areas	8.07 global; 1.11 for 26; 6.96 for TC
77285	Intermediate	Two separate treatment areas	13.56 global; 1.67 for 26; 11.89 for TC
77290	Complex	Three or more treatment areas, or any number of areas with particle therapy, rotation or arc therapy, complex blocking, custom shielding blocks, brachytherapy, hyperthermia probe verification, or any use of contrast	13.22 global; 2.45 for 26; 10.77 for TC
77293	Add-on	Respiratory motion management simulation (4D acquisition), reported with 77295 or 77301	12.03 global; 3.12 for 26; 8.91 for TC

The level is set by the number of treatment areas unless one of the listed complex items was present at the time of simulation. Two items make a one-area case complex more often than people expect: contrast and a custom shielding block. Note that 77290 carries fewer total RVUs than 77285 in 2026 (13.22 versus 13.56) because its technical component is lower; its professional component is still the highest of the three.

The simulation note needs, in every payer manual we read: the treatment site, the type of images taken (or a statement that a clinical simulation without imaging was performed), the immobilization devices constructed, and the physician’s signature and date.

Once per course, and when a second one is allowed

Simulation is a per-course service with narrow exceptions, and the exceptions are payer rules. The Medicare Claims Processing Manual’s radiation oncology chapter covers management, bundled services, delivery, brachytherapy and physics and has no simulation section, so for Medicare the rules come from the CPT descriptors, the MUEs and the NCCI manual.

Situation	What payer manuals allow
Initial simulation, non-IMRT course	One unit of 77280, 77285 or 77290 per phase of treatment (eviCore); one initial simulation per modality (Evolent)
Verification simulation, non-IMRT	One 77280 per phase, coded simple regardless of the number of areas (eviCore, Evolent)
Any simulation during an IMRT course	None; 77301 includes simulation-aided field setting (NCCI chapter 9, eviCore, Evolent)
Several sites in one course	Simulate them in the same encounter; no additional units for sequential simulations in the same episode (eviCore)
Virtual simulation	Not reportable with 77280 to 77290 (eviCore)
Brachytherapy	One 77290 before the initial implant, then one 77280 per subsequent treatment to verify applicator and source position (eviCore); partial breast HDR allows two simulations a day (NCCI, Evolent)
Superficial or orthovoltage course	No simulation code; 77436 covers planning and field setting
Re-simulation for a re-plan	A new CT data set showing a meaningful change in anatomy or target volume, with a physician statement of medical necessity, supports a new plan (Evolent); the simulation follows the per-phase rule for non-IMRT and is still bundled for IMRT

The NCCI manual also bars billing the two on different dates. The IMRT plan “includes therapeutic radiology simulation-aided field settings,” and although the edits apply to the same date of service, “these edits shall not be circumvented by performing the 2 procedures described by a code pair edit on different dates of service.” Separately, 77280 to 77290 “shall not be reported for verification of the treatment field during a course of IMRT treatment.”

77293: the respiratory motion add-on

77293 pays for acquiring the multiple data sets that capture target motion during breathing. It is an add-on (global period ZZZ), so it is never billed alone; eviCore pairs it with 77295 or 77301 on the same date and allows it once per episode of care. It is not reportable for sites that do not move with respiration (eviCore names prostate, brain and rectum), nor for CT registrations taken only at inspiration or expiration or for deep inspiration breath hold. In the hospital it is packaged (status N) with no separate technical payment, though the physician still bills 77293-26.

The same-day image guidance warning

The 2026 image guidance code 77387 is professional-only everywhere, which has led some practices to bill 77387-26 from the first fraction. If the verification simulation falls on that same date, two payer manuals say one of them will not be paid. eviCore: “If a simulation, port films, or IGRT are performed on the same date of service, then only one type of imaging can be reported.” Evolent: IGRT procedures “and simulations are not billable on the same date of service, for the same treatment site.” The safe pattern is verification simulation on its own date before treatment starts, then 77387-26 on treatment dates.

Worked example: a lung course and a prostate course

Course A: 3D conformal lung, 30 fractions, freestanding center, Medicare. CT simulation with IV contrast and a 4D acquisition, then a 3D plan. Illustrative national amounts: RVUs times 33.4009, before geographic adjustment and sequestration.

Line	Why	Units	Allowed (national)
77290	Contrast makes it complex regardless of area count	1	441.56
77293	4D data set for a moving target, reported with 77295	1	401.81
77295	3D plan with DVH	1	485.32
77280	Verification simulation before fraction 1, on a different date from any 77387-26	1	269.55

In a hospital department the physician bills the same four codes with modifier 26 (81.83, 104.21, 224.79 and 37.08) and the hospital bills 77290 under APC 5612 (382.54 in the 2026 Addendum B), 77295 under APC 5613 (1,414.11), 77280 under APC 5611 (137.32), and nothing for 77293.

Course B: IMRT prostate, 28 fractions, same center. Simulation is performed, immobilization built, images acquired. The claim shows 77263, 77301, 77338, 77300 units and 77387-26 on treatment days. No 77290 and no 77280, not on the simulation date and not on any later date. The simulation work is paid through 77301.

What to do

• Code the level from the note, not the machine. Count contiguous treatment areas, then check the complex list (contrast, custom blocks, arc, brachytherapy).
• Bill one initial simulation per course or phase and one verification 77280 per phase for non-IMRT courses, on its own date.
• Remove simulation codes from every IMRT course before the claim goes out; a 77280 dated two weeks after 77301 is still a bundled service.
• Report 77293 with its primary plan code on the same date, once per course, and only for respiratory sites.
• Denials to recognize: CARC 97 (included in another service) on 77280 to 77290 with 77301, or on 77293 billed alone; CARC 236 (incompatible procedure combination) when simulation and 77387-26 are billed on the same date; CARC 151 when a second 77290 posts in one course. The first two are generally not appealable; the third is a correction when the units are wrong, or an appeal with the re-simulation documentation when a new data set was genuinely required.
• Iridium Suite’s claim scrubber checks each simulation line against CCI edits and payer rules as it is entered, so a 77290 keyed during an IMRT course is flagged before it reaches the claim.

Related terms

• 77407 vs 77412: choosing the treatment delivery level
• 77387 modifier 26
• Modifier 26 and TC
• Radiation oncology modifiers
• Adaptive radiotherapy billing in 2026
• Medically unlikely edits

Further reading: CMS Medicare NCCI Policy Manual (2026 edition; chapter 9 is Radiology Services); CMS Medicare Claims Processing Manual, Chapter 13; CMS PFS Relative Value Files; eviCore Radiation Oncology Coding Manual V1.0.2026 for Cigna (PDF).