Millennium MLC—The standard in conformance
With years of experience throughout the world, Varian offers the most complete range of multileaf collimators (MLC) available today. With Varian's fine leaf Millennium™ 120 MLC, clinicians can provide patients with the treatment precision and accuracy previously available only with customer compensators and blocks.
Treat Even the Smallest Lesions
Varian's unique MLC design enables clinicians to treat minute lesions, including those that respond well to stereotactic techniques. IMRT fields up to 34 x 40cm are quickly treatable as a result of fast leaf speed, and high precision and interdigitation capabilities.
Clinical Benefits:
- Broad range of MLCs to meet clinical needs and budget
- Accurate and improved dose distributions
- Replace customer blocks
- Perform all types of MLC-driven IMRT treatments
- Increase patient throughput with existing equipment
- Digital MLC field creation and edit
- Recording of every leaf position nominally every 50ms
- Interdigitation
- Fast leaf speed and high precision
MLC Options Available:
- 52 leaf Millennium MLC
- Field size 26 x 40cm
- Leaf widths 10mm
- 80 leaf Millennium MLC
- Field size 40 x 40cm
- Leaf width 10mm
- 120 leaf Millennium MLC
- Field size 40 x 40 cm
- Central 20cm of field: 5mm leaf width
- Outer 20cm of field: 10mm leaf width
Dynamic Control—DMLC
Standard on the Trilogy system, this dynamic MLC capability delivers IMRT using either a segmental approach with step-and-shoot or a dynamic approach with sliding window delivery.
Advanced Capabilities:
- IMRT: MLC leaf motion during static gantry beam delivery.
- Electronic compensation: MLC leaf motion during static gantry beam delivery. Used to perform a uniform dose at a user specified plane.
- Dynamic conformal arc therapy: MLC leaf motion during gantry rotation. The leaves dynamically conform to the tumor outline.
- Intensity-modulated arc therapy (IMAT). A series of arcs with gantry and MLC motion throughout.
- 500 MLC segments per field
The dynamic high-resolution Millennium MLC is a key part of the Trilogy system for exquisite beam sculpting
All Millennium MLCs offer:
Description:
- Drive independence: Each leaf and carriage drive is independently controlled
- Leaf orientation: Leaf movement in the “X” direction (parallel with lower jaws)
- Leaf interdigitation: Adjacent leaves from opposing banks can move past one another
- Maximum leaf retract position: 20.1cm (from beam centerline)
- Maximum leaf extend position: -20.0cm (over beam centerline)
- Maximum distance adjacent leaves on same carriage: 15.0cm
- Maximum field length "X" direction: 40.0cm
- Leaf height: 60.0mm
- Leaf end radius: 80.0mm
- Leaf tongue and groove offsets: 0.4mm
Performance:
Physics
- Coincidence light field vs. X ray: 1mm
- Penumbra 20–80% leaf end: For a 10 x 10cm field, 7mm or less for X-ray energies < 10MV 8.5mm or less for higher energies
- Average transmission leaf: < 2.5
- Maximum interleaf leakage: < 4.0
Leaf Position Accuracy
- End accuracy: 1.0mm at isocenter
- End repeatability: 0.5mm at isocenter
- Side accuracy: 1.0mm at isocenter
- Side repeatability: 0.5mm at isocenter
Position Initialization
- Leaf position initialization datum: Optical beam mechanically fixed to collimator assembly
- Initialization time: Approx. 5.0 minutes
- Leaf position configurability: User can specify leaf end position offsets to achieve desired optical- or isodose-based leaf positions using carriage and leaf position calibration files