Varian VitalBeam

The machine accelerates electrons to high energy and directs them onto a target to produce a photon beam, or delivers the electron beam directly for superficial treatment. A multileaf collimator in the treatment head shapes the field with computer-controlled leaves that move continuously during delivery. The gantry rotates around the patient, and a treatment couch positions them precisely. Imaging equipment is mounted on the same gantry: a kilovoltage tube and flat panel detector produce two-dimensional images and cone beam computed tomography, while a portal imager records the treatment beam itself. The system connects to the department's treatment planning and record and verify software, so the plan approved by the radiation oncologist and the physicist is what the machine executes, with interlocks that stop delivery if anything deviates. Within the manufacturer range this is the simpler, reduced-option machine: it shares the beam physics and the planning and imaging ecosystem of the TrueBeam platform, but offers fewer energy and dose-rate modes, no high-definition collimator, and stereotactic body radiotherapy and motion management as optional configuration rather than as standard equipment, so what a given department can deliver depends on how its own machine is configured.

Planning begins with a computed tomography scan taken in the treatment position, in the immobilisation device the patient will use every day, with other imaging fused in where it defines the tumour more clearly. The planning system calculates a dose distribution that covers the target and limits dose to the surrounding organs, and physics verifies the plan by measurement before treatment starts. At each session, the patient is set up on the couch and an image is taken and matched against the reference; the couch shifts and rotations are applied automatically. Delivery then proceeds, most often as one or two arcs in which the gantry rotates while the collimator leaves and the dose rate change continuously, so the high dose region conforms to the shape of the tumour. Where the target moves with breathing, a gating system tracks the respiratory trace and switches the beam on only during the chosen phase of the cycle. The patient lies still and feels nothing.

The platform treats the cancers usually managed with external radiotherapy: breast, prostate, lung, head and neck, gastrointestinal, gynaecological, brain, lymphoma, sarcoma and others, along with palliative treatment for painful bone metastases, bleeding or obstruction. It supports radical courses given alone or combined with chemotherapy, preoperative and postoperative treatment, and hypofractionated schedules that deliver a higher dose per session over fewer visits. Its stereotactic body radiotherapy capability allows a small number of high-dose sessions to selected targets such as early lung tumours in patients who cannot have surgery, spinal metastases and a limited number of metastatic deposits. It helps departments with a large treatment load in particular, because the setup and delivery are quick and the imaging is built in. The radiation oncologist chooses the technique, dose and schedule for each patient.

Patients experience short daily visits, most of which is spent on positioning and imaging rather than on the beam itself. Nothing is felt, and the patient is alone in the room but under continuous camera and audio observation. Daily image verification means the plan is delivered to the intended place even when internal organs shift, which permits tighter margins and less dose to healthy tissue. Side effects depend on the region treated, the dose and the schedule rather than on the machine, and are managed by the team over the course: tiredness, skin changes in the treated area, and site-specific effects such as sore swallowing, bowel or bladder irritation. Courses range from a single palliative session to several weeks of daily weekday attendance. When treatment is arranged away from home, the number of sessions is the main planning factor, since attendance must be uninterrupted, and the department confirms the schedule before the course begins.