Proton therapy

Last updated date: 30-Oct-2023

Originally Written in English

Proton Therapy

Proton therapy, also known as proton beam therapy, is a type of radiation therapy. It precisely directs proton beams on the cancerous cells. It can convey a greater dose to a particular location with minimal effect on nearby tissues. Hence, proton therapy is safer safe, and much effective, unlike conventional radiotherapy. 

A radiologist administers radiation therapy to cancer patients using a high-energy beam of protons rather than high-energy x-rays. Generally, proton therapy is an advanced radiation therapy currently available. It kills the cancerous cells while causing less damage to healthy tissue, unlike traditional radiation. Furthermore, it’s not painful and is non-invasive.


Reasons for Proton Therapy 

Proton therapy is essential in treating cancer and other benign tumors. Radiologists can recommend this therapy as the primary treatment for the health problem. Alternatively, it can be used along with different types of treatments, including chemotherapy and surgery. 

In addition, proton therapy is useful in removing the cancer cell that remains or recurs following conventional x-ray radiation. At times, the radiologist can use proton therapy to address medical conditions such as;

  • Breast cancer 
  • Brain tumors 
  • Eye melanoma 
  • Cancers affecting children 
  • Esophageal cancer 
  • Liver cancer 
  • Neck and head cancers 
  • Lung cancer 
  • Liver cancer 
  • Lymphoma 
  • Pituitary gland tumors 
  • Pancreatic cancer 
  • Sarcoma 
  • Prostate cancer 
  • Tumors affecting the base of the skull 
  • Tumors of the spine 


Preparing for Proton Therapy 

Before undergoing proton therapy, the healthcare team will walk you through the whole planning course to make sure that the proton beam gets to the target location where it is required in the body. 

Typically, the planning process entails:

  • Choosing the best treatment position for you

The radiation therapy specialist works to identify a comfortable and more suitable treatment position for you during radiation simulation. Since it’s critical that you remain still during the procedure, being in a relaxed position is vital. 

The healthcare team will position you on a table designed for use during the treatment to accomplish this. Restraints and cushions will help position you correctly and keep you still. The radiologist will mark the part of the body getting exposed to proton therapy radiation. Alternatively, you may get permanent tattoos or a temporary marker. 

  • Using imaging tests to plan the pathway of the protons

Computerized tomography (CT) or magnetic resonance imaging (MRI) scans may be performed to identify the part of the body to treat. These imaging tests also help determine the best way for the proton beams to get to the target area. 


What does Proton Therapy Involve?

proton therapy center

Proton therapy is typically administered five days per week in the radiation or proton therapy center for a few weeks. But based on your health condition, you might only need one or several treatments in some cases. Although the actual proton therapy can only take a few minutes, plan on spending about 30 to 45 minutes getting ready before every session. 

Furthermore, you might be subjected to weekly CT scans to determine whether your dose requires recalculation. This depends on the changes in weight or shape and the size of the tumor. 

The healthcare team will position you on a table and prepare you for the treatment. To ensure that you remain still, they will use cushions and restraints. Before undergoing every treatment, you will have an imaging test, including a CT scan or x-ray. This is to ensure your body remains in the same position. After that, the radiation therapy team will exit the treatment room to monitor you in another area. They are still able to see and even hear you.

Proton therapy is delivered using a machine known as a gantry. This machine focuses the proton beams at specific points on the body. When the device is switched on and begins delivering the proton therapy dose, you will hear it. During the entire treatment, however, you will not feel the radiation. 


How Proton Beam Therapy Functions

Typically, proton therapy is a type of advanced radiation therapy that employs protons rather than x-rays. Protons are large particles compared to those found in conventional radiation. They deliver more of the energy in the tumor. Such a burst of energy can be seen as the Bragg peak on a graph.

The protons immediately stop after releasing the energy to the cancerous site or tumor. However, they don’t leave the tumor and enter the healthy tissue nearby. Due to this, proton therapy lowers exposure to radiation and the possible damage to the surrounding healthy tissue. This is particularly in sensitive parts, including the brain, spinal cord, eyes, heart, nerves, and major blood vessels. 


What to expect after Proton Therapy?

You can resume your normal activities after the therapy session is done. You will not be radioactive or emit radiation. 

Proton therapy side effects normally appear with time. At first, you might have a few side effects. However, after a number of treatment sessions, you may feel fatigued. This makes it appear as if your everyday activities require additional energy or you have less energy for daily tasks. Also, you might detect skin redness that looks like sunburn within the part in which the proton beams are aimed. 

The radiologist can suggest periodic imaging tests throughout and even after proton therapy. This helps identify if your condition is effectively responding to the treatment.


Benefits of Proton Therapy 

Doctors can recommend proton therapy for cancer or tumors in children and adults, both malignant and benign. It is most useful when treating spinal cord and brain tumors in children, who frequently suffer long-term side effects due to other toxic treatments for cancer. In addition, the radiologist can suggest proton therapy for breast cancer instead of other treatments like chemotherapy. 

Also, proton therapy can provide several advantages due to its increased precision and accuracy, including:

  • Reduced healthy tissue damage: Proton therapy can lower the radiation dose on the nearby healthy tissues by 50 to 70%. This indicates reduced tissue damage to the vital areas around the tumors and a low risk of radiation-related complications later in life.
  • Few mild side effects: The side effects might be mild because the radiation only affects less healthy tissue. Damages to sensitive structures like the heart, brain, esophagus, oral cavity, and spine are reduced.
  • Higher radiation dose: Because there is less risk of surrounding tissue damage, the radiologist can increase the dose to the tumor. A higher dose may be more successful in killing the cancerous cells.
  • The ability to address malignancy in critical parts: Because of the precision of proton therapy, it is a great choice for tumors around the essential body organs and radiation-sensitive tissues.


Risks of Proton Therapy 

Side effects of proton therapy can occur as the cancerous cells die or if the proton beam energy destroys the healthy tissue surrounding the tumor. 

Unlike conventional radiation therapy, proton therapy is thought to impact the less healthy tissue and cause few side effects. This is because radiologists can better regulate where the greatest energy concentration is released. Proton therapy does, however, generate some of the energy on the nearby healthy tissue. 

The side effects you develop will be determined by the area of the body receiving treatment as well as the proton therapy dose you get. Generally, the following are some of the most prevalent side effects associated with proton therapy:

  • Exhaustion
  • Skin redness within the region being treated
  • Hair loss in the area of the body receiving treatment
  • Soreness in the area of the body getting treatment


Proton Therapy versus Radiation Therapy

Proton Therapy versus Radiation Therapy

Proton therapy has the potential to convey up to 60% less radiation on the healthy tissue surrounding the target area. On the other hand, it delivers an increased dose on the tumor. Also, during proton therapy, the medical provider can control when and where the proton emits the majority of the energy. This allows for maximum destruction to the tumor cells while causing minimal damage to the surrounding tissue.

In radiation therapy, the beams of x-ray release energy alongside their pathway before reaching their target, such as on the surface of the body and further. The x-ray beam travels beyond the cancerous site, emitting energy and causing tissue damage. This is known as the exit dose.

This typically means that the treatment affects not only the target malignant cells but also those alongside the x-ray beam prior to and after the tumor. This might result in health issues following treatment.

The radiologist can employ a high radiation dose with proton therapy, unlike the standard radiation therapy. However, they can as well protect the nearby tissue and the essential body organs.

Also, with the radiation therapy, the radiologist might need to use a lower than the desired dose to avoid damaging healthy cells. This could, however, reduce the efficacy of the treatment. 



Although it is expensive, Proton beam therapy tends to be a safer and effective treatment for many cancers. However, the additional costs might be worth it in terms of better health and improved quality of life for some people. Moreover, less time is lost because of complications in the future and the negative effects associated with conventional radiation therapy.

With additional development, proton therapy could become a new and valuable cancer treatment option. However, you should first talk to your medical provider about this treatment if you want to try it.