ESTRO 2021 Abstract Book

S1460

ESTRO 2021

Conclusion The DcmCollab Audit Tool has proven itself a powerful companion when performing audit trials. Before the introduction of the Audit Tool, generating, distributing, and managing proper and DICOM compliant materials for audits was a task ranging between “very time consuming” and “practically insurmountable”. The number of audit trials supported by the Audit Tool in DcmCollab indicates that it is a significant step towards minimizing the workload, allowing a large increase in the number of audits performed by the Danish centers. Future development will focus on supporting the data analysis following an audit, ie. population measures of DVH and contour similarity, compliance with guidelines etc.

PO-1737 Design of a rotatable head fixation for cranial stereotactic treatments O. Sauer 1 , S. Wegener 1 , R. Schindhelm 1 1 University of Würzburg, Department of Radiation Oncology, Würzburg, Germany

Purpose or Objective Stereotactic treatments become more and more frequent. Recently the treatment of multiple targets in the brain with a single isocenter is about to become a standard. Accurate delivery of STX techniques requires, besides the translational, an exact rotational relation of the cranium to the radiation device. The general, but expensive solution is the use of a 6D robotic couch. While head immobilization systems with variable pitch are available, we designed a device, where also yaw and roll are adjustable. Materials and Methods rotatable plate is fixed by a ball joint, placed near the neck, to a base plate beneath the patient. The base plate holds the head of a patient with the aid of a thermoplastic mask. The adjustment mechanism is placed around the body axis at the cranial end of the base plate. Care was taken to minimize the diameter of the mechanism in order not to spoil non-coplanar beams. The angles are adjustable with hand wheels whose axis grab into sprockets related to the desired rotations. A prototype was built with parts produced with a 3D printer. The device was tested with a head phantom. A stereotactic treatment was planned. The entrance field contours were marked on the surface of the phantom after it was adjusted with a robotic couch with the aid of CBCT image registration. The device with the head phantom was rotated using the robotic couch to produce