Problem

When treating breast cancer tumors, sometimes intraoperative radiation therapy needs to be performed. This consists of a radiation treatment that’s administered directly to the tumor during a surgery.

 

When performed, the collimator (where the radiation stream circulates) and the affected zone (tumor) need to be perfectly aligned so that the radiation goes only where it should. The current way to make this happen is to sew a cover (where the metallic disc sits) on the tumoral tissue so that it doesn’t move and then position the collimator on top of it. This last step is performed manually and is therefore not very precise leading to frequent target volume underdosage and/or organs at risk irradiation.

 

Solution

In order to solve the misalignment problem, together with the oncology and biomedical engineering department, we designed and prototyped a new “centering” tool that sits between the collimator and the metallic ring acting as a connector.

 

This new centering tool is 3D printed with polyamide and is composed of three pieces:

• a disc that is adapted to the collimator tube diameter

• a cover (substitute of the conventional one) where the tumor is anchored and that is adapted to fit on top of the metallic disk

• a screw that connects everything and prevents undesired shift or rotation between pieces

 

We have designed different screw lengths to be changed depending on prescribed dosages. Shorter screws will make the two pieces closer together and therefore both the source of radiation and the tumor will be closer, increasing the dosage received.