Radiotherapy, also called radiation therapy, is a highly targeted, highly effective way to destroy cancer cells.

Radiotherapy uses high-energy rays to damage cancer cells and stop them from growing and dividing.  It is a localised treatment which aims to destroy the cancer cells with as little damage as possible to the surrounding normal or healthy cells.

What is Radiotherapy?

Radiotherapy can be delivered in many different ways from outside (externally) or inside (internally) the body.

External Radiation Therapy: known as External Beam Radiotherapy, is delivered from a machine known as a linear accelerator. It is usually given on an outpatient basis in a hospital or clinic 5 days a week for a number of weeks. 

Internal Radiation Therapy: known as Brachytherapy, is a method used to deliver high dose radiation to a small volume of tissue. It can come in the form of a temporary or permanent implant. Depending on the type of cancer, it will require a short stay of a few days in hospital or can be performed as an oupatient procedure.

  • With radiotherapy, the side effects depend on the treatment dose and the part of the body that is treated.

    The most common side effects are:

    • Tiredness
    • Skin reactions in the area being treated (such as a rash or redness, permanent pigmentation, and scarring)
    • Loss of appetite
    • Inflamation of tissues and organs
  • Will I be radioactive after my treatment?

    The radiation you receive delivers its dose to the treatment area instantaneously. There is no lingering radiation once the treatment machine is turned off. If you are treated with external beam radiation, you will not be radioactive at any time. 


    Does radiotherapy cause hair-loss?

    Radiotherapy is a “local” treatment, which means it is directly focused on just the affected area. Therefore patients will only lose hair in that area. Unless radiation is targeted at your head, you will not lose your hair from the treatment.


    Does radiotherapy make you feel sick?

    Radiotherapy may cause a sensation of feeling sick or vomiting if your abdomen or pelvic area is being treated. You will be advised if this is a possible side effect of your particular treatment and appropriate medication will be prescribed, if necessary.


    Does radiotherapy involve the use of radium?

    Radiotherapy is the careful use of invisible high-energy x-rays to treat cancer and does not involve the use of radium.

  • External Beam Radiotherapy is the term used to describe radiotherapy that is delivered using machines called Linear Accelerators by a team of Radiation Therapists.



    The treatment takes place inside a special treatment room which you will be inside for 10 - 15 minutes.

    Once inside the room you will need to remove or loosen your clothing and lie on a treatment couch.

    The Radiation Therapists will align you with the treatment machine and may take x-ray images to assist with this process.

    When the Radiation Therapists have completed the set-up process, they will leave the room to switch on the treatment machine. When the machine is switched on you will hear a humming or buzzing noise. You should lie still and breathe normally while the radiation beam delivers your treatment. It is a painless procedure.

    This treatment is generally carried out Monday - Friday, for a period of 7 weeks.

  • Intensity-Modulated Radiation Therapy (IMRT) is a specific type of external beam radiotherapy that uses a technique of modifying the radiation beam to the exact size and shape of your particular tumour.

    The beam delivers high doses of radiation specifically to the tumour tissues while sparing surrounding organs, therefore reducing the risk of injury to healthy tissues.

  • There are 2 types of brachytherapy treatment available: low-dose rate and high-dose rate.

    High Dose Rate (HDR)

    This is mainly used to treat cancers in the head and neck area, the cervix, womb, prostate or the skin. 

    High-dose rate (HDR) brachytherapy is a type of internal radiotherapy that delivers radiation from implants placed close to, or inside, the tumor(s) in the body.

    Prostate Cancer

    For patients with prostate cancer at an advanced stage, high dose rate (HDR) brachytherapy is used to deliver a very high radiation dose boost to the prostate. This is normally prescribed in combination with a course of IMRT external beam radiotherapy.

    The process involves implanting several needles into the prostate under ultrasound guidance.

    A patient will first have a CT scan with the needles in place. The exact position of each needle and the organs in close proximity are mapped out.

    Following careful planning, the needles are attached to a treatment machine where a radioactive source is automatically pushed into each needle where it remains for just a few moments. 

    The implanted needles are removed following the treatment and no radioactivity remains in the patient.


    Low Dose Rate (LDR)

    This involves placing radioactive seeds directly into your tumour and leaving them there permanently. In Ireland, LDR brachytherapy tends to be used for treating men with prostate cancer. This treatment is commonly known as Radioactive Seed Implantation (RASI)


    Radioactive Seed Implantation

    The Mater Private Hospital was the first hospital in Ireland to introduce Prostate Seed Brachytherapy. Since 2002, we have treated over 500 patients using this technique. It is particularly suitable for patients whose prostate cancer is in the earlier stages.

    The process involves the Surgeon implanting up to 90 radioactive seeds into the prostate in carefully planned positions. The positioning of these seeds is determined using a combination of ultrasound images and advanced software, which updates the position of each seed as it is implanted and re-calculates the dose based on the actual position of seeds. This is called ‘real-time’ planning, and it allows the Surgeon to modify and correct the delivery of the treatment to ensure the best possible outcome.

    The radioactive seeds used are I - 131. These release radiation over a very small distance, allowing a sufficient dose to be given to the prostate while significantly protecting the surrounding healthy organs of the rectum and bladder from any damage. The seeds are left in place permanently and their radioactivity diminishes over time.