Retiro De Equipo (Recall) de Oncentra External Beam (formerly known as Oncentra MasterPlan during release of v3.x)(Radiation therapy treatment planning software)

Recall

RC-2016-RN-01655-1

Class II

2016-12-22

Australia

DHTGA

https://apps.tga.gov.au/Prod/sara/arn-detail.aspx?k=RC-2016-RN-01655-1

If a physical wedge, for which the total field size limit perpendicular to the wedge direction is more than 10 cm larger than the field size limit in wedge direction, is inserted in in-plane direction (as seen with collimator angle 0 degrees), then with very large fields perpendicular to wedge direction a part of the scattered fluence can become unmodulated by the wedge. this will result in profile “horns” close to the edge of the field. the deviation is most prominent with the varian 60-degree wedge. the calculated overdose in the affected areas, towards the edges of the field, is typically 6% for clinically used field sizes locally. smaller deviations inside the field can also be observed with the varian 45-degree wedge. with all other inplane wedges, including the elekta motorised wedge, there is only an insignificant deformation of the cross profile tail, which is outside the treatment field.

Elekta will be correcting the issue in the next upgrade of the Oncentra External Beam. In the interim, users are advised to not exceed jaw positions of +/- 12cm with the Varian 60-degree wedge and +/- 14.5 cm with the Varian 45-degree wedge in the direction perpendicular to the wedge slope, if the wedge is inserted in in-plane direction (collimator angle 0 degrees). In addition, Elekta is strongly advising users to perform proper Quality Assurance for all treatment plans before delivery of the first fraction to the patient.