New MRI-Guided Therapy Navigates Magnetic Seed Through Brain to Heat and Destroy Tumors

The therapy, demonstrated by scientists at University College London (London, UK), in mice, is called “minimally invasive image-guided ablation” or MINIMA and comprises a ferromagnetic thermoseed navigated to a tumor using magnetic propulsion gradients generated by an MRI scanner, before being remotely heated to kill nearby cancer cells. The researchers say their findings establish ‘proof-of-concept’ for precise and effective treatment of hard-to-reach glioblastoma, along with other cancers such as prostate, that could benefit from less invasive therapies.

In the study, the UCL team demonstrated the three key components of MINIMA to a high level of accuracy: precise seed imaging; navigation through brain tissue using a tailored MRI system, tracked to within 0.3 mm accuracy; and eradicating the tumor by heating it in a mouse model. Ferromagnetic thermoseeds are spherical in shape, 2 mm in size and are made of a metal alloy; they are implanted superficially into tissue before being navigated to the cancer. MRI scanners are readily available in hospitals around the world and are pivotal in the diagnosis of diseases such as cancer. The work at UCL shows that MINIMA has the potential to elevate an MRI scanner from a diagnostic device to a therapeutic platform.

“MINIMA is a new MRI-guided therapy that has the potential to avoid traditional side effects by precisely treating the tumor without harming healthy tissues,” said senior author, Professor Mark Lythgoe (UCL Centre for Advanced Biomedical Imaging). “Because the heating seed is magnetic, the magnetic fields in the MRI scanner can be used to remotely steer the seed through tissue to the tumor. Once at the tumor, the seed can then be heated, destroying the cancer cells, while causing limited damage to surrounding healthy tissues.”

“Using an MRI scanner to deliver a therapy in this way allows the therapeutic seed and the tumor to be imaged throughout the procedure, ensuring the treatment is delivered with precision and without having to perform open surgery,” added lead author, Rebecca Baker, (UCL Centre for Advanced Biomedical Imaging). “This could be beneficial to patients by reducing recovery times and minimizing the chance of side effects.”

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