Singapore: Study results published in the current issue of British Journal of Urology International demonstrate that new software to register and fuse information from magnetic resonance imaging (MRI) and ultrasound (US) images enables intraoperative visualization of tumors, not ordinarily seen in a US image. This technology has the potential to support new tissue-preserving treatments for prostate cancer, such as focal therapy.

In the study, "Image-Directed, Tissue-Preserving Focal Therapy of Prostate Cancer: a Feasibility Study of a Novel Deformable MR-US Registration System" researchers from University College London (UCL) evaluated the feasibility of using a computer-assisted, deformable image registration software to enable three-dimensional, multi-parametric MRI derived information on tumor location and extent to inform both the planning and treatment phase of focal high intensity focused ultrasound (HIFU) therapy using SonaCare Medical's Sonablate® 500 system.

Nested within the multi-center INDEX Trial, this pilot study employed computer assisted MRI-US image registration software within the planning of the first 26 men with a MRI-visible tumor treated at UCL with HIFU using a tissue-preserving quadrant, hemispheric (hemi) or extended hemi ablation therapy. Results demonstrated that the software, developed at UCL, enables information of tumor location to be used for therapy planning using the Sonablate® 500 system without adding significant extra time to the standard procedural workflow. Such planning is particularly important for new tissue-preserving treatment approaches to ensure that the tumor is completely treated.

"Multi-parametric MRI has shown promise as an accurate method for determining the focality of tumors, and has promise as a potentially important enabler for minimally-invasive, tissue-preserving, or focal, HIFU treatments. However, most ablative technologies for localized prostate cancer use an ultrasound platform to plan and deliver treatment, on which the tumor cannot be accurately localized. This often results in discrepancies between the tumor and target volumes, potentially leading to under-treatment at the margins, or treatment of larger tissue volumes to compensate for inaccuracies in targeting," said lead author Dr Louise Dickinson of UCL. "We are very pleased that the results of this pilot study demonstrate that deformable image registration is feasible and safe when introduced into a HIFU ablative therapy setting and suggests potential for improving the accuracy of targeting lesions using a tissue-preserving focal therapy approach."

The research is based on breakthrough image analysis algorithms developed at the UCL Centre for Medical Image Computing and has undergone extensive clinical evaluation as part of clinical research studies led by Professor Mark Emberton, Professor of Interventional Oncology and director of the Division of Surgery and Interventional Science at UCL. Twenty-six prostate cancer patients have been successfully treated at UCLH using the Sonablate® 500 with the aid of this software as part of the INDEX Trial.