Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - AdapTT (Real time therapy planning for Thermal based therapy modalities in oncology care.)

Teaser

MotivationAssisting Minimally Invasive Cancer Treatments Minimally invasive procedures have been gaining ground in recent years, due to the many advantages they offer by reducing the operation costs, the patients recovery time and discomfort and the risk of side-effects and...

Summary

Motivation

Assisting Minimally Invasive Cancer Treatments

Minimally invasive procedures have been gaining ground in recent years, due to the many advantages they offer by reducing the operation costs, the patients recovery time and discomfort and the risk of side-effects and infection. For the purposes of this project we focus on thermal based ablation of hepatic lesions. In particular we aim at improving the planning and guidance tools for radio-frequency based ablation treatments, by providing information to the physician, such as the optimal placement of the needle and the outcome of the ablation, prior and during the operation.

Objectives

1. Development of a multi-scale biophysics model, which accounts for the cooling effect caused by blood vessels during RF ablation. The model should be accurate and fast enough for clinical use..

2. Improving the accuracy and effectiveness of ablation treatments, by developing reliable and computationally efficient optimization routines, which can be used not only for pre-operative planning, but also during the treatment.

3. Development of reliable experimental validation methods for the above described numerical models. The validation can rely either on the measurement of temperature fields or on the assessment of the size of the ablation zones. An ultimate goal, of this experimental part would be a real-time feedback to the planning tool to enable an adaptive therapy.

Work performed

Following results are achieved so far:

- Dedicated phantoms were developed able to visualize the temperature effect due to different treatment modalities, which are used for validation of model development.
MR fingerprinting (and MR thermometry) experiments are performed to investigate the possibility to determine the relevant tissue parameters as input for modelling and to measure temperature maps in ex-vivo tissue experiments.
First experiments show promising results.

- The main challenge while modelling the temperature distribution during treatment in the liver is to account for the effect of blood vessels. Different modelling techniques are being studied and benchmark cases have been defined
to test the different vasculature descriptions.
First sensitivity studies are performed using different model descriptions for cooling effects of vasculature < 1mm.

- For the 2D case, the optimization problem is defined and different methods are tested and studied. An optimization strategy is defined and the implementation of RB model order reduction started. Furthermore, a first 3D
optimization case has been set-up for needle placement, using deformable domains.

- The software platform is prepared with a first basic implementation.
On a regular base, updates of the tool are available and software infrastructure is in place to incorporate methods/learnings from the AdapTT activities.

Final results

AdapTT research will result in knowledge and components that will and are used into interventional oncology guidance tools for focal thermal tumour treatment, developed at the industrial partner.
This application is a first step in a vision towards achieving the same level of standardization in thermal focal therapy, compared to the current standard-of-care being radiotherapy.
This opens the door for further uptake and better outcome results for patients undergoing this type of cancer treatment.

The research focused around RF ablation in liver and specifically the ESR’s achieved:
• Inverse planning methodologies and software code to calculate upfront the best treatment strategy for a patient.
Novel model order reduction techniques were used to reduce the calculation times, making it usable for clinical practice.
The work resulted in several publications and a patent application, demonstrating the novelty of the approach.
• MR fingerprinting techniques and concepts are developed to be able to detect patient specific tissue properties, important for input to thermal models predicting treatment efficacy (planning).
Furthermore, dedicated experiments (phantom, ex-vivo and ex-vivo perfused liver) are executed as first validation of the thermal models. Especially the MR fingerprinting and ex-vivo perfused liver experiments
are novel methodologies giving new insights and also resulted in different publications and a patent application.
• One of the major problems in thermal focal treatment in liver is the heat sink effect of blood vessels. Modelling and experimental studies are done to quantify the effects resulting
in effective model descriptions, usable in the therapy guidance application, meaning computational efficient without unacceptable loss in accuracy.

Website & more info

More info: http://www.adaptt-thermal-therapy.eu.