PROTON THERAPY CENTER - Advantages of Proton Therapy

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Advantages of Proton Therapy

How does radiotherapy work?

Radiotherapy is basically performed in two ways. The first, known as Brachytherapy, involves the precise
placement of short-range radiation-sources (radioisotopes) directly at the site of the cancerous
tumor. Its use is limited by the anatomical location of the tumor and the fact that it is only precise in small
areas. Brachytherapy has a precisely defined usage, the indication spectrum of which is significantly narrower in comparison with external radiotherapy.

More frequent is external beam radiotherapy, i.e. irradiation with sources located outside the body of the
patient. Currently the most widespread type is conventional (classic) photon radiotherapy and also
particle radiotherapy with particles of atomic nuclei (protons, neutrons) or nucleus (helium, carbon).

The biological effect of conventional and proton therapy is the same. The beam carries a certain energy and when it passes through tissue, it is retarded and the energy is transferred to the tissue. The extent of this energy depends on the weight and speed of the particles. A conventional beam reaches up to 30 MeV (mega-electron volts), because the weight is approaching zero, whereas a proton beam reaches one order higher (200–230 MeV). For didactic purposes the comparison of a ping-pong ball
to a golf ball is sometimes used.

Advantages of proton therapy

Přednosti protonové léčby

Advantages of proton therapy

During conventional radiation, a beam of photons
transfers the greatest dose of radiation to the front of the tumor, after which the radiation penetrates the tumor and healthy tissues of the patient behind the tumor. In contrast, a proton beam transfers a minimal dose of radiation to the front of the tumor, a maximal dose to the tumor area itself and no dose behind the tumor. Therefore, proton therapy is safer for healthy
tissue surrounding the tumor.


 

The use of advanced methods of conventional radiotherapy such as intensity modulated radiotherapy (IMRT), where the tumor is irradiated with beams of variable intensity or techniques of stereotactic radiotherapy (such as the CyberKnife or Gamma Knife) have provided significant dose distribution improvements in the tumor and surrounding healthy tissues. These techniques provide very exact high dose irradiation to a small target area, usually by a large number of thin, focused beams of intense ionizing radiation with a decrease in radiation outside the target area. The physical properties of
photons however, even using these advanced methods, do not change and healthy tissues are not completely protected from radiation damage. In addition, the use of stereotactic radiotherapy is limited to only very small tumors.

Proton beams also transfer energy into healthy tissue in front of the tumor but much less so, depending on the depth of the tumor under the body surface. The center of the tumor receives 70 – 80 % of the beam’s energy. The beam is rapidly delayed at that point and transfers its destructive effects directly to the tumor cells. The energetic value of the beam decreases behind the tumor to zero. Tissues behind the tumor lying in the direction of particle motion are - in contrast to conventional radiotherapy - completely protected. Since the current technology enables irradiation with a proton beam from many directions and irradiation may be well modulated (IMPT – Intensity Modulated Proton Therapy), there is
the possibility of completely protecting vital organs near the tumor from any damage.

  

Proton beams can be used for the treatment of malignant tumors where therapeutic possibilities are restricted and conventional radiotherapy is associated with a high risk of adverse effects. This is particularly in the case of childhood tumors, eye tumors and for those in some areas of the brain. This is a unique property of proton therapy. With all other tumors proton therapy always shows a lower risk of adverse effects, making proton radiotherapy a clear treatment choice for the future.

Advantages of proton therapy in comparison with currently used conventional radiotherapy:

  • Minimal damage to healthy surrounding tissues and the possibility of treating tumors situated near important organs and structures - with definite benefit in the treatment of paediatric tumors.
  • A low risk of adverse effects during and after termination of therapy with radiation - and faster recovery for patients having completed therapy.
  • Precise targeting of tumors with maximum protection of healthy tissue during irradiation - significantly reduces the risk of developing secondary malignant tumors.
  • High probability of complete eradication (destruction) of tumor cells and a higher probability of long term survival.
  • Ultimately, cost savings resulting from the costs that would have arisen due to subsequent medical and social care for untreatable patients or patients suffering from significant adverse effects after conventional therapy.

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