VMAT12

VMAT12 is a proposed configuration within the field of radiation oncology that extends the principles of Volumetric Modulated Arc Therapy (VMAT). It is described as a twelve-arc delivery approach designed to improve dose conformity and reduce treatment times by using twelve independently modulated gantry arcs within a single treatment session. The designation “12” refers to the number of arcs or beam segments used during optimization, though implementations vary by vendor and clinical protocol.

Technology and delivery involve combining dynamic multileaf collimator modulation with rapid gantry rotation, advanced optimization algorithms, and high-quality imaging for alignment. Modern systems may integrate on-board imaging such as cone-beam CT or other 3D/4D modalities to enable adaptive radiotherapy, where treatment plans can be adjusted in response to patient anatomy changes between or during fractions.

Clinical use and considerations suggest that VMAT12 can improve dose fall-off around targets and spare surrounding organs at risk, particularly in complex geometries such as head and neck or thoracic tumors, while reducing overall treatment time. Limitations include greater planning complexity, quality assurance requirements, and potential for longer upfront commissioning. Robust imaging, motion management, and QA are essential for safe and effective use.

History and status: The VMAT12 concept gained attention through research in the 2010s as a high-arc extension of VMAT. It remains an area of ongoing study, with vendor-specific implementations and clinical investigations rather than a single universal standard.

See also: Volumetric Modulated Arc Therapy, Intensity-Modulated Radiation Therapy, adaptive radiotherapy, image-guided radiotherapy.