A New Era - MR in linacs

QA when treating with a MR-linac!

The MR-linac has been clinically available for more than 2 years and now some clinical information is also available. It is impressive what possibilities are made available with this new technology but there are also new risks involved with radiation treatments in very intense magnetic fields. These challenges are something everyone in the process has to take into account.

Outstanding accuracy
ScandiDos has followed the development of this new technology and in parallel developed the Delta4 Phantom+ MR to perform high quality Pre-Treatment Verification of the radiation therapy in high magnetic fields. The goal has been to make the Delta4 Phantom+ MR as accurate and reliable as the Delta4 Phantom+, a product of which we have sold nearly 800 units.

The configuration of the Delta4 Phantom+ detector arrays and the unique dose per pulse measurement did not have to be changed for the Delta4 Phantom+ MR, it is a perfect concept for the MR-field. The two crossing detector-arrays are even more important in the MR-field when QA must not rely on interpolations but rather real measurements in all points during the entire treatment delivery. This is unique and this is why the Delta4 Phantom+ provides outstanding accuracy. Another benefit with the two crossing arrays is that they do not create “Faraday-cage issues”.

The Delta4 Phantom+ MR can be cross-calibrated against an ionization chamber that is inserted into the phantom but the chamber is not required to receive absolute dose during measurements. The diode arrays provide absolute dose distribution directly.

Conducting comprehensive testing that started four years ago together with the inventors of MR-linac – UMC Utrecht, we have learned what is required to make a pre-treatment system run safely with high accuracy in MR-linac fields and redesigned the electronics to meet the new challenges.

Görgen Nilsson,
CEO and President ScandiDos AB