MapCHECK IMRT QA

Mapcheck IMRT QA

MapCHECK is the proven worldwide leader in filmless IMRT QA. It is preferred due to the small size of its diode detectors (0.000019cm³), higher sensitivity (10 times that of ion chamber arrays), and superior detector stability. MapCHECK avoids the dose volume averaging problems seen with ion chambers and because IMRT beams are collections of small fields with steep dose gradients, this is a critical MapCHECK advantage. With over five years of clinical use, MapCHECK is designed to provide efficient and complete analysis tools such as structure import, MLC QA, and Beam QA.

Ideal for Rotational Dosimetry Although no two dimensional array configuration is geometrically ideal for rotational dosimetry, independent testing shows that the MapCHECK performs strongly for this new QA challenge. Importantly, the diode based MapCHECK performed as well if not better for rotational modalities compared to ionization chamber arrays.

MapCHECK Hardware
MapCHECK measures absolute dose at 445 detector locations, with 221 detectors concentrated in the critical 10 x 10cm field – the highest detector density of any 2D array. MapCHECK is not susceptible to the problem of dose volume averaging as seen with ion chambers, as well as the noise and reproducibility problems commonly seen with film.

Mapcheck IMRT QA

Because MapCHECK dose values are absolute, there is no need for a separate chamber point measurement. MapCHECK does not require frequent calibration (typically no more than once per year) and can be self-calibrated in 15 minutes.

Measure Large Fields

Mapcheck IMRT QA

Rotate 1800 & Combine

Large field measurement is handled with the MapCHECK combine tool. For example, a 32 x 32cm field with 1256 detectors is possible using the combine tool. Fields of up to 40 x 40cm are supported.

MLC QA
MapCHECK detector resolution can provide film-less MLC QA. MLC measurements are compared to corresponding picket fence plans, giving an average error and standard deviation of MLC leaf positions.

Because of MapCHECK’s high detector resolution, leaf bank position error can be detected to 0.2 mm. A 1mm leaf error is represented in MapCHECK MLC QA as a 20% error.

Structure Filter Analysis
Import Dicom RT structure sets from the Treatment Planning System (TPS) and make clinically relevant decisions based on the patient anatomical structures. The structure filter easily determines whether failing regions of the beam intersect critical anatomy. This analytical tool gives clinical relevance to the failing points, enabling a more informed QA decision.

Structure setup information is automatically imported with the patient structures to assure structures are presented in the beams eye view for actual gantry angle.

Gated Delivery & Target Motion QAThe MotionSim XY/4D™ is a sophisticated hardware and software upgrade option for all MapCHECK users. MotionSim XY/4D works with the MapCHECK as the only treatment simulator that can reproduce actual target motion (projected to BEV motion for each beam) obtained from a 4D CT (or other methods).

Mapcheck IMRT QA

A programmable gating surrogate is included, which is compatible with both RPM and belt systems. MotionSim XY/4D completely simulates an in-motion target to assess the dose distribution to the target, for gated and non-gated deliveries. Treat the MapCHECK array while it is on the MotionSim XY/4D to see dose distributions accumulate in real time with the effects of the actual target motion.

MapCHECK Software
With a single mouse click, MapCHECK compares measured dose points to planned dose points. Users can compare normalized data or absolute dose data using distance to agreement or Gamma. Three adjustable criteria guarantee maximum flexibility and are easily adjusted. Measured points that do not fit within the acceptance criteria are highlighted red for high dose and blue for low dose.

Threshold Isodose percentage line that defines the dose area to evaluate.

Dose Difference Planned dose is subtracted from measured dose and the difference is evaluated.

Distance to Agreement If dose difference is not satisfied then planned points are searched within a user defined radius for a value that corresponds to the measured point at the center radius.

Concise Summary Provides the exact picture of the measurement result in percentage / pass / fail indications.

Calc Shift Determines if there is a misalignment between the measured & planned dose maps.

Other Software Features
    • Flatness & Symmetry (Beam QA)     • Histograms
    • Isodose Overlay/Subtract
    • MLC QA
    • File Management
    • Gamma Analysis
    • Film Analysis (including        Gafchromic)
    • Structure Filter Analysis
    • EPID Data Analysis
    • Profiles
    • User Calibration
    • Reports (including PDF)

1175000-0 MapCHECK IMRT QA

MapCHECK Filmless IMRT QA