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The Benchmark for 3D VMAT QA

The ArcCHECK is the world’s most selected independent 4D measurement array. Simply connect the single cable which supplies both power and data, and start to measure. No background measurements, no warm-up, no separate inclinometers, no additional hardware rotisseries.

Volumetric Measurement QA for Patient Plan, Dose and Machine Testing

ArcCHECK is the only true 4D array specifically designed for QA of today’s modern rotational deliveries. At its heart are over 1300 SunPoint® Diode Detectors providing consistent and highly sensitive measurements for all gantry angles, with no additional hardware required. Independent absolute dose measurements enable the gold standard for stringent and efficient patient plan and machine QA testing.

Patient Plan QA
Stringent, fully independent measurement QA of patient plan and delivery with SNC Patient software

Dose and DVH QA
Full 3D Dose reconstruction for target and OAR DVH QA with 3DVH® software

Machine QA
Dynamic machine QA testing routines are provided for a wide variety of tests with SNC Patient software

ArcCHECK embodies the spirit of independent Medical Physics measurement.

  • 1386 SunPoint® Diode Detectors (0.019 mm3)
  • Consistent Beams Eye View (BEV) for all gantry angles measuring entrance and exit dose
  • Real-time electrometer measures every pulse, as well as composite and sub-arcs
  • Interior cavity allows wide range of detector and inhomogeneity inserts

Measuring completely around the isocenter in a uniform manner for each angle is a more stringent measurement than a simple composite dose at the isocenter. Errors visible in the isocenter are also visible in the surrounding dose measurements, but in more detail.

ArcCHECK measures entry and exit dose for every angle. For each beam angle, ArcCHECK measures high dose regions at the entrance and low dose regions at the exit, detecting potential delivery and TPS modeling errors for both high and low dose levels. For those who would like to measure the dose at isocenter or elsewhere within the cavity, Sun Nuclear offers the versatile MultiPlug and CavityPlug with detector insert.



  • Hounsfield Unit (HU) conversion testing
  • Tissue equivalent inserts:
    • Muscle, Bone, Lung, Adipose, Titanium
  • Dose in up to 25 locations
  • Film cassette insert
  • Bezel angle indicator for rotation within cavity
  • Precision milled detector holder included
    • Solid insert included to achieve solid cavity
Cavity Plug


  • Precision fitted to ArcCHECK cavity
  • Measure dose in cavity center
  • Precision milled detector holder included
    • Solid insert included to achieve solid cavity

An Ideal Geometry
Phantoms are ideally shaped like a patient. The cylindrical design of ArcCHECK intentionally simulates patient geometry to better match reality.

ArcCHECK detectors are always facing the delivery beam regardless of gantry angle. The detector geometry relative to the BEV remains constant. Detection of very small gantry angle errors is possible. In contrast, when a 2D array is irradiated obliquely, the geometry collapses to 1D. Even when there is no detector shadowing effect, significant information is lost on a 2D array, and errors up to 10° are missed 75% of the time.

With ArcCHECK, gantry angle, leaf-end position, absolute dose, and time (4D) are measured and correlated to identify sources of error. Dose accuracy is improved and errors can be traced to the treatment planning system, the delivery system, or the imaging system.

What You See with a 2D Array

2D Array Measurement
An inherent limitation of 2D arrays is an inability to capture all of the dose information for rotational deliveries.

What You See with ArcCHECK

ArcCHECK Measurement
ArcCHECK displays BEV dose distribution throughout the entire arc delivery. More data is available to perform a more thorough QA analysis.

Helical Detector Grid

Detectors are arranged on a HeliGrid™ which increases the sampling rate and reduces BEV detector overlap and shadowing.

  • An ArcCHECK 10 x 10 cm2 area contains 221 detectors; equivalent to the detector density in a MapCHECK® 2
  • Entrance and exit dose are measured, effectively doubling the detector density in the measurement field

Virtual Inclinometer

ArcCHECK calculates gantry angle independently using entrance and exit dose.

  • Virtual Inclinometer is accurate to ±0.5°
  • Avoids additional inclinometer cables and mounting to the delivery system.

Easy Setup

ArcCHECK contains a sophisticated yet easy to use leveling system that ensures a quick and accurate setup.

  • Built in rotation and tilt inclinometers, the leveling LEDs relay setup status in real-time.

Large Fields

Two ArcCHECK measurements can be combined in SNC Patient software
for larger field sizes.

Small Fields

Merge feature provides 442 detectors within a 10×10 field.

2D Dose Analyse

2D Dose Analysis

With a single mouse click, SNC Patient Software compares measured ArcCHECK dose points to planned dose points. Compare normalized data or absolute dose data using Distance to Agreement (DTA), Gamma (γ), and Gradient Compensation.

VMAT / Kontrollpunktanalyse

VMAT / Control Point Analysis

Individual control points and user-defined arc sections can be analyzed for a full arc or sub arc. A 360° presentation of pass, low, and high dose summary for the defined control point range and sub arcs is presented.


MLC Analysis

Evaluate the difference between the planned and delivered MLC pattern, and identify leaves that may indicate required service. Additional machine QA tests are also included.

3DVH uses ArcCHECK QA measurements to estimate 3D dose to the patient geometry.

  • Perform 3D dose and DVH QA analysis on patient – not phantom – geometry
  • Supports coplanar and non-coplanar beams
  • Identify TPS and beam delivery errors
3DVH Phantom Evolution

Phantom Evolution

3%/3mm criteria showing 99.2% passing rate, a good test of deliverability and machine performance.

Clinical Evaluation

Clinical Evaluation

Evaluating the same plan, 3DVH shows substantial target underdose, indicating that although the plan was properly delivered, the clinicial impact was below expectations

Respiratory MotionSim

Respiratory MotionSimTM

Simulate the dosimetric impact of target motion with proven accuracy.

  • Evaluate motion impacts on 3D Dose and DVH
  • Determine if motion management is necessary, and add to QA motion management plans
  • Use existing QA measurements and avoid bulky mechanical motion phantoms
MachineQA Analyse

Machine QA Analysis

Use ArcCHECK for a wide variety of machine QA tests in dynamic and rotational mode.

  • Dynamic Gantry Rotation QA
  • Dynamic Gantry Angle QA
  • Dynamic Gantry Speed QA
  • Dynamic Symmetry and Flatness
  • MLC QA
  • Treatment Reproducibility QA

Detector Type: SunPoint® Diode Detectors
Detector Quantity: 1386
Detector Spacing (cm): 1.0
Array Diameter (cm): 21.0
Array Length (cm): 21.0
Cavity Diameter (cm): 15.0
Inherent Buildup (g/cm2): 3.3
Inherent Backscatter (g/cm2): 3.3
Detector Physical Depth (cm): 2.9
Array Geometry: Helical Grid (HeliGrid) 1 cm offset
Phantom Material: PMMA (Acrylic)
Active Detector Area (mm2): 0.64
Detector Sensitivity (nC/Gy): 32.0
Max Dose/Pulse (Gy): 0.003
Detector Volume (mm3): 0.019
Detector Stability: 0.5% / kGy at 6 MV
Dose Rate Dependence: ± 1%, 75 – 250 cm SSD
Update Frequency (ms): 50
Number of Connection Cables: Single power/data cable
Dimensions (cm2): 27.0 x 43.0
Weight (kg): 16.0

System Requirements (SNC Patient, EPIDose, 3DVH)

Operating System: Windows XP, Windows 7, Windows 8.1
CPU: Recommended 2.4 GHz or better, multi‑core (2 or more cores)
RAM: Recommended 4 GB or more
Hard Drive Space: Recommended 5 GB or more


FFF: Yes
MR: Yes (ArcCHECK-MR®)

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