Bubbles and protons against cancer

X-ray therapy is an important weapon in the fight against cancer. Approximately 50 percent of patients are cured with this technology. Unfortunately, the use of X-rays does not prevent damage to surrounding tissues. Proton therapy, another form of radiation, is a better choice in this respect. The depth of penetration and energy delivery of the radiation dose can be set very precisely, so that the damage to healthy tissues is minimal.

Unfortunately, it is still very difficult to determine for each patient what the ideal dose is at what time, and at what specific place in the body the dose should be delivered. Just like organs, tumours do not stay where they are, they move around. In addition, different types of tissue inhibit the protons that are sent into the body in different ways, which makes it difficult to predict how deep the protons will penetrate.

Nico de Jong and colleagues want to combine so-called 'micro-bubbles' (gas-filled bubbles that are used as a contrast agent in ultrasound) with a highly sensitive optical-acoustic receiver. Through the interaction of protons with the bubbles, weak acoustic high-frequency (2 MHz) pressure waves are created, which can be measured with such a receiver. This allows doctors to monitor in real time whether the protons are getting to the right place in a patient's body. The receiver is being developed in collaboration with the Acoustics and Sonar departments, and Optics of TNO.  The operation of bells and receivers will be validated at the proton centres of HollandPTC and ZonPTC.

Project leader: Prof. Dr. N. de Jong (Delft University of Technology)
Erasmus MC, TNO The Hague, TNO Rijswijk, TNO Delft, HollandPTC, Bracco, Maastro Clinic, Maastricht University, Smart Photonics, ZonPTC.