Intensity modulation using multileaf collimators: current status.
Intensity-modulated radiation therapy (IMRT) extends the capability of 3D conformal methods (3D-CRT). Studies show that these methods can clinically reduce complications and can allow a larger safety margin for dose escalation. The ultimate goal is improved survival and improved quality of life. IMRT methods typically require more fields, or segments, and more monitor units for a given dose, as compared to conventional CRT methods. Because of this, some multileaf collimator (MLC) parameters take on more importance. A review of current standard MLC configurations are discussed, along with the concept of integral dose. An effective quality assurance (QA) program for IMRT involves more than dose modeling of the MLC. Integrity of data flowing from 3D radiograph databases to treatment planning to delivery sequencing files to verify-and-record function is required. End users need to be aware of differences in commercial availability vs. in-house developments for configuring a system. Great strides have been made in streamlining the whole process. This is evidenced by the first major symposium on community-based IMRT. Research continues to improve accuracy and productivity.
Carlson
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Siemens Medical Systems, Inc., Concord, CA 94520, USA. dcarlson@smsocs.com
D006801:Humans; D020266:Radiotherapy, Conformal / Q000379:methods*