Tumor target motion is a significant factor in inhibiting increasing levels of accuracy. The development of X-ray volume imaging (XVI) and its suite of imaging tools was driven by the need to visualize internal structures within the reference frame of the treatment system in order to reduce geometric uncertainties. The ability to image at the point of treatment and in the treatment position reduces issues relating to organ movement and inspires clinical confidence to pursue IMRT delivery.

Imaging at the time of treatment

XVI acquires and reconstructs the 3D image data simultaneously with low imaging doses. This precision can be repeated accurately with image quality that has isotropic sub-millimeter resolution.

XVI does this by using an innovative XVI technology that is integrated directly onto the treatment system itself. This means that routine 3D volume imaging of a tumor can now be performed immediately prior to treatment.

This decreases the risk of target positioning error or geographical miss due to tumor or internal organ motion. In addition, since the patient doesn’t have to be moved from an imaging device (eg. MR, CT) to the radiation therapy treatment machine, the risk of errors from re-positioning the patient will also be reduced.

Using 3D VolumeView™, clinicians can visualize soft tissue detail in any area of the body. This unique functionality offers potential benefits:

• advanced treatment delivery requires increased confidence in the position of target anatomy and proximity of critical structures only 3D imaging can provide this confidence
• the ability to minimize side effects of radiation therapy by reducing the margins previously set to account for uncertainties of target dimensions, location and movement and improve patient outcomes
• the potential to adopt dose escalation and hypofractionation regimes with the confidence that a 3D plan will be delivered as an accurately targeted 3D treatment.

Clinical collaboration

XVI was developed by Elekta in close collaboration with clinical partners, ensuring the features, functionality and efficiency meet the needs of all modern clinics. Working closely with the Elekta Synergy Research Group, Elekta became the first company to support research on IGRT, the first to bring 3D volumetric imaging into clinical use and the first to bring these solutions to the wider market.

XVI imaging technology

Planning and treating in 3D requires verification in 3D. The 3D imaging capability of XVI enables the clinician to take full advantage of complex technique dose delivery without the need for implanted target surrogate markers to visualize soft tissue structures, target volume and critical structure position. It allows precise registration of the reconstructed image data with the historical CT planning data as a non-invasive procedure. XVI offers a variety of image guided options to suit the individual needs of the patient and the clinic The XVI software offers the flexibility to vary the dosage necessary to acquire a VolumeView image, depending on the level of contrast required.

Key visualization advantages offered by VolumeView imaging at the time of treatment include:

• soft tissue size, shape and position
• critical organs and tumors
• bony anatomy and alignment in 3D
• eliminate the need for surrogate markers
• ability to minimize the imaging dose
• overlay of structures defined in treatment planning system
• large field-of-view
• simultaneous acquisition and reconstruction