What is Proton Therapy?

Radiation therapy which can produce a focused effect only on a tumor

Proton therapy is a type of radiation therapy. Radiation can be divided into two major types. One is electromagnetic ray represented by x-ray and gamma ray, and the other is particle beam which includes proton beam and carbon ion beam.
In proton therapy, hydrogen nuclei (protons) are used for treatment after raising their energy level with a particle accelerator, such as cyclotron and synchrotron.

Proton therapy can not only create a concentrated effect on a target tumor but also has fewer side effects compared to conventional radiation therapy. Thus it is expected to make a potent effect on a tumor which has been considered difficult to treat.

Our center can provide more precise proton therapy by performing CT, MRI, or PET-CT scans before and after the irradiations.

Characteristics of Proton Therapy

Controls the proton beam to deposit a large focused amount of radiation right into a tumor

Proton beam has some unique behaviors when it is compared to x-rays which is widely used in conventional radiation therapy. Proton therapy has gotten a great deal of attention as one of the effective cancer treatments with fewer side effects than x-rays by utilizing those unique behaviors.

Unlike proton therapy, conventional radiation therapy uses x-rays which enter the body and deposits most of its energy in normal tissues near the body surface, then the energy reduces down as it goes towards the center of the body. X-rays also continue to penetrate through the tumor and irradiate much of the healthy tissue behind it. This undesirable pattern of energy placement can result in unnecessary damage to healthy tissue, thus it is considered an inefficient treatment.

Proton beam, on the other hand, has a characteristic called the “Bragg peak” which delivers its maximum dose at a precise depth then completely stops to irradiate.
In proton therapy, the shape and depth of the Bragg peak are precisely controlled to conform to the shape and the size of a tumor, which enables physicians to provide a focused treatment on the tumor.

Proton beam has a characteristic called the “Bragg peak”, which enables emitting the highest radiation dose at the set depth. Bragg peak adjusted to conform to the lesion is called Spread-out Bragg peak.

Effectiveness of Proton Therapy

Reducing side effects and damages to healthy tissue

Because of the characteristics of the Bragg peak, proton therapy can reduce damage to healthy tissue behind the cancer lesion. This means that proton therapy can reduce side effects compared to other radiation therapies such as conventional radiation therapy uses x-rays.

Great benefits to your life during and after treatment

The great advantage of reducing undesirable effects on healthy tissue result in a great benefit to your life during and after treatment.

For example, conventional radiation therapy inevitably damages optic nerve when treating a tumor in between your eyes, which leaves you with no choice but to be treated at the risk of blindness. However, with proton therapy, irradiation to healthy tissue can be reduced or prevented, thus treatment can be done with far less damage to the optic nerve. This outcome entirely changes your life after treatment and significantly improves quality of life afterwards.

Benefits of Proton Therapy

  • Less damage to healthy tissue and fewer side effects
  • Can be treated on an outpatient basis
  • Can irradiate cancer cells nearby tissue vulnerable to radiation
  • Reduces the likelihood of secondary tumors caused by radiation therapy in pediatric and young patients
  • Able to treat elderly patients and patients who cannot undergo a surgery due to complications
  • Maintains the shape and functions of surrounding tissues , thus less likely to affect patients' day-to-day life during and after treatment

About Side Effects (Risks)

It is important to fully understand the side effects of proton therapy before getting treated.

Proton therapy has far fewer side effects than conventional radiation therapy because proton therapy targets a tumor with high precision and radiates only in a limited area with needed amount of radiation.

Radiation itself doesn’t cause any pain or heat. However, we cannot be absolutely certain that it’s wholly free from side effects. Symptoms of its side effects differ depending on cancer site, direction of radiation, and radiation dose. Also, it has been found that side effects appear differently on different patients.

It is important to discuss with your doctor, taking account of the above, before treatment and fully understand the possible side effects/adverse reactions and how to manage them when they actually appear.

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