August 29, 2011 – Elekta announced it has received approval to CE Mark its Integrity R1.1 treatment control system in the European Union. Integrity R1.1 combines a three-tier safety system with continuously variable dose rate (CVDR) and interdigitation capabilities for Elekta's MLCi2 multi-leaf collimator (MLC). Integrity supports a complete range of delivery techniques –– including intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and stereotactic applications –– while ensuring maximum patient safety.
Incorporating three tiers of safety, Integrity has undergone rigorous tests in eight international centers, which demonstrated safe reductions in treatment times of as high as 30 percent. The approval of the CE Marking for Integrity enables European medical centers to realize these treatment speed and safety benefits when Elekta begins delivery of the control systems.
"We depend on Integrity to ensure that the linac does what it is supposed to do," says Prof. Frank Lohr, vice chairman of University Medical Center Mannheim (UMC, Germany). "Our data, using Integrity on a variety of plans, shows that VMAT plans are significantly accelerated and treatment delivery is considerably smoother than with the previous control system. On average, Integrity has reduced treatment times by 20 to 30 percent."
UMC is one of eight centers that participated in testing Integrity and has used the Integrity R1.0 control system for a year on two on Elekta treatment machines that are dedicated almost exclusively to delivering IMRT and VMAT. Efficiently delivering these complex techniques has been facilitated by CVDR and MLC interdigitation, both enabled via Integrity.
"Because 60 percent of all our patients received IMRT –– with 70 percent of that group receiving VMAT –– the ability of Integrity to support MLC interdigitation and CVDR becomes even more critical, as they greatly enhance treatment delivery speed," Prof. Lohr observed. "Integrity has shown to be a good, reliable product –– it does what it should and does it well, enabling us to provide the benefits of IMRT and VMAT to patients who will benefit most from these modulated therapies. Integrity also will help us fully exploit future innovations."
Integrity combines a three-tier safety system with CVDR and interdigitation for Elekta's MLCi2. The first Integrity safety tier records and verifies the prescription received from Mosaiq oncology information system (OIS) and checks that all linac parameters are set correctly. The second tier checks and controls MLC leaves, gantry, collimator and dose delivery throughout beam delivery, ensuring that all parameters are in the correct position and the right dose is being delivered. Guardian, the third tier, supervises the proper operation of the other two tiers –– verifying in real-time that the field currently being delivered matches the prescribed treatment parameters. If a discrepancy occurs, Guardian will stop the treatment.
Interdigitation and CVDR boost efficiency
With interdigitation, MLC capabilities have caught up with the ability of the treatment planning system to create fields with complex geometry. Because MLC leaves can move past one another (i.e., interdigitate), clinicians can employ island fields in difficult cases, such as those involving multiple targets. Interdigitation is important not just for treating multiple targets but also when there is a target geometry that consists of different dose objectives. For example, clinicians may want to treat a primary target to 70 Gy and a nodal region to 57 Gy.
CVDR allows the dose rate to be adjusted to its ideal MU value during delivery of both dynamic and VMAT prescriptions. This option makes prescription delivery smoother and faster when compared to previous discrete dose rates. The additional dose rate options permit Integrity to easily navigate complex dose modulation paths.
*Integrity is not available for sale or distribution in all markets. Contact your Elekta representative for further details.
For more information: www.elekta.com