What is Proton Therapy ?

What is Proton Therapy ?

A guiding principle of all radiation therapy is that it should affect the tumour as best as possible, while affecting the surrounding healthy tissue as little as possible. The properties of certain types of tumours make it difficult to strike a good balance between destroying the tumour and sparing the healthy tissue. Proton therapy (radiotherapy using protons) may prove helpful in the treatment of such tumours.

Proton irradiation is a different form of radiotherapy (for an explanation click below on 'What is radiotherapy?'). In contrast to photon therapy, proton therapy using particles. These particles (the protons) are the building blocks of atomic nuclei, and as so small as to be invisible.

What is radiotherapy?

Radiotherapy is a type of (usually cancer) treatment using radiation. Radiotherapy is therefore also known as radiation treatment.
There are various types of radiation, with each type using a different type of radiation, namely:

  • Photon Radiation
    The most common form of radiotherapy is photon radiation. Photon radiotherapy is comparable to Röntgen radiation (known mainly for its use in X-rays and CT-scans), with the exception that the photon carries substantially more energy (penetrability).
    In the Netherlands, around 50,000 patients receive internal or external treatment using photons every year.
  • Electron Radiation
    Electrons are particles that carry a negative load, and a very minor weight. Due to their load and minor weight, their penetrability is (substantially) lower than that of photons. Electron radiation is used in the treatment of superficial tumours, such as skin tumours. 

Radiotherapy is a localised treatment, meaning that radiation is restricted to tumour or the area where the tumour and/or any metastases are located.
The objective of using radiotherapy is to destroy the cancerous cells. The radiation damages the genetic material (the DNA) inside the cell. If the damage to the DNA is severe enough, the cancerous cells lose their ability to divide, and begin to die off.

The University Medical Centre Groningen (UMCG) Radiotherapy department uses advanced radiotherapy technology, including the aforementioned photon and electron radiation methods. As of January 2018, these are supplemented with proton radiotherapy. Proton radiotherapy will be made available at the UMC Groningen Proton Therapy Centre (UMC GPTC), part of the UMCG Radiotherapy department. 

The difference between dosing in a photon plan and a proton plan. The difference between dosing in a photon plan and a proton plan.

In order to establish whether proton radiation would benefit a patient, the two methods first need to be individually compared. Individually, because the radiation treatments are simulated using previously made CT-scans of the patient. These scans are used to simulate the treatments using a computer: one using photon radiation, and one using proton radiation.

Proton therapy is only opted for if using proton therapy would significantly reduce the chances of developing side-effects when compared to photon therapy.