SRS MapCHECK® removes film and subjectivity from SRS/SBRT QA, offering streamlined, digital testing for improved Patient Safety. More than 650 users worldwide have adopted SRS MapCHECK for fast, accurate and film-less stereotactic QA workflows. A growing body of publications confirm its unique clinical versatility and efficiency.

SRS MapCHECK supports the prevention of treatment errors for a broad range of stereotactic radiosurgery and radiation therapy delivery systems -- from conventional C-arm linacs to Accuray's CyberKnife® System.

Move Beyond Film
SRS MapCHECK takes the place of film and expedites the workflow for time-sensitive patient QA. It's a consistent, easy-to-maintain method for high-density absolute dose measurements.

Irradiate from Any Angle

With the StereoPHAN, SRS MapCHECK uses a patented technique to account and correct for angular dependence, and pairs that with field size and pulse rate corrections to ensure accurate dose measurements from any angle, including vertex fields.

Flexibility, Speed, Accuracy, as if Verified by Film
Proven to efficiently detect output factor, MLC, and grid size errors, SRS MapCHECK prevents the most common sources of SRS treatment errors.

NEW in SNC Patient v8.5
With the release of SNC Patient software version 8.5, SRS MapCHECK now offers CyberKnife® System Machine QA, making it the only device that supports Machine QA and Patient QA for CyberKnife. New capabilities include MLC QA, Iris Beam QA and Targeting Accuracy QA (TAQA).

Watch this AAPM 2021 presentation for an overview of new features for CyberKnife QA and more >>

"As our SRS program grew, we quickly realized that film was not going to cut it. The SRS MapCHECK is equivalent to film on a good film day and greatly exceeds it on a bad film day, all while saving significant time. The size of the array is sufficient, and the user-friendly software guides us through setup. We’ve measured up to 20 targets in one plan and confirmed each and every met was calculated accurately.”

  • Mark W Geurts, MS, DABR, CQE
  • Aspirus Health

Go from 300 Minutes to 10 Minutes
With SRS MapCHECK, the whole process takes just 10 minutes:

  1. Insert the SRS MapCHECK into the StereoPHAN™.
  2. Deliver the beam.
  3. Compare absolute planar dose to the TPS plan.

High Density, Unmatched Diode Detector Resolution

The 2.47 mm detector spacing in SRS MapCHECK provides 5 detectors within a 5 mm field, enabling measurements as small as 5 mm — the smallest clinically used field size at most sites. Combined with an unmatched 0.48 mm detector resolution and patented angular dependence correction, SRS MapCHECK supports robust QA and task group requirements.

Real-Time Results
With SNC Patient™ software, SRS MapCHECK provides immediate, accurate results. No trips back and forth into the room, and no time to wait for film to develop.

Import the QA plan, and SNC Patient compares the dose distribution of the treatment plan file to the actual measured values (absolute and relative dose).


Smaller, High Density Arrays vs. Larger, Lower Density Arrays for Stereotactic QA

Performing patient-specific stereotactic QA on plans with multiple targets and a single isocenter can be complex. Radiation therapy teams rely on arrays to ensure treatments will be delivered as expected. This clinical note explores the importance of detector density in arrays for measuring stereotactic patient QA.

CTA srsmc diode

Unmatched Diode Detector Resolution

Detector Spacing and Resolution measures field sizes down to 5 mm (5 diodes in 5 mm cone).

TG-218 Angular Dependence Support

Within SNC Patient™ software, patented, robust angular corrections detect and adjust for translational offset between compared datasets with precision of 0.1 mm. Results are film equivalent, meeting TG-218 requirement for angular dependencies to be accounted for in 2D arrays.

TG-101 Support

To minimize volume averaging errors, TG-101 suggests that SRS measurements should be performed with a detector <1mm. SRS MapCHECK supports this requirement with detectors well under the limit.

Couch Kick Compatible

Optimization-based Calculation Shift algorithm supports co-registering measurements to patient planned dose with 6 degrees of freedom.

Quick, Reproducible Measurements

SRS MapCHECK has no warm-up period and uses its own diodes to determine gantry angle of measurement – no additional electrometer or inclinometer required.

Easy Stereotactic Program Commissioning

For departments adopting SRS/SBRT, SRS MapCHECK is a proven, published, easy method for absolute planar dose measurements. The StereoPHAN enables rotation and measurement across different dose planes.

Start saving time on your SRS QA.


St. Joseph’s/Candler Health System – Nancy N. and J.C. Lewis Cancer & Research Pavilion

Savannah, Georgia


Accurate and Efficient QA of Single-Isocenter Multiple-Target (SIMT) Plans


SRS MapCHECK® & SNC Patient™

St. Joseph’s/Candler Health System – Nancy N. and J.C. Lewis Cancer & Research Pavilion

Varian Medical Systems® is a registered trademark, and Varian™, TrueBeam®, Edge®, VitalBeam, Trilogy™, Halcyon™, and Ethos™ are trademarks, of Varian Medical Systems, Inc. Sun Nuclear Corporation is not affiliated with or sponsored by Varian Medical Systems, Inc.





Device Specifications

Detector Type

SunPoint® 2 Diode Detectors

Detector Quantity


Detector Spacing (mm)


Active Detector Area (mm x mm)

0.48 x 0.48

Array Size (mm)

77 x 77

Detector Sensitivity (nC/Gy)


Sampling Frequency (ms)


Dose Rate Dependence

+/- 1.0% (100 MU/min to 2400 MU/min

Inherent Buildup (g/cm2)


Inherent Backscatter (g/cm2)


Radiation Measured

Photons: 6 MV, 10 MV, 6 FFF,10 FFF

Number of Connection Cables

Single power/data cable

Dimensions (L/W/H)

320 x 105 x 45 (mm)

Weight (kg)



Varian Medical Systems® and Elekta

Supports C-arm (TrueBeam®, Edge®, VitalBeam, Trilogy™, C-Series, Versa, Synergy, Infinity, Axesse, Compact), Halcyon™, and Ethos™


Supports TomoTherapy®, Radixact® and CyberKnife®

System Requirements (SNC Patient)

Operating System

Windows 10 Pro 64-bit


Recommended 2.4 GHz or better, multi-core (2 or more cores)


Recommended 4 GB or more

Hard Drive Space

Recommended 5 GB or more