IGRT increases target accuracy of radiotherapy
For a long time, radical surgery of the prostate was the only successful treatment method for prostate cancer. However, there are now highly modern methods of radiation therapy. The advantage: The radiation of the tumour is gentler at the same healing rate; incontinence and impotence occur much less frequently than during surgery. As a pioneer in the field of brachytherapy (internal radiation), the West German Prostate Center (WPZ) has expanded its spectrum to include one of the most modern radiation therapy facilities in Europe. On September 1,2009, the radiotherapists of the WPZ, Dr. Gregor Spira and Dr. Carsten Weise opened a new large department in the oncology therapy centre on the right bank of the Rhine in Cologne. On an area of 1000 sqm, in a new building flooded with light, patients are irradiated precisely and safely with state-of-the-art high-tech technology.
Marksmanship in demand
The more precisely the radiation hits the tumor in the prostate, the greater the success of the treatment,"explains Dr. Spira. An optimal radiation dose in all parts of the prostate can optimize the chances of healing. At the same time, a high radiation exposure of neighbouring organs can be avoided, which leads to a reduction of unwanted side effects.
The precise positioning of the patient underneath the radiation source is therefore a prerequisite for a high accuracy of the radiation therapy. Even if the patient is positioned very precisely every day, the position of the tumor can deviate from the expected position by a few centimeters due to internal movements,"explains the radiotherapist. The position of the prostate gland in particular, along with the large intestine and bladder, can shift depending on the amount of urinary bladder. According to Dr. Spira, irradiation can therefore only be optimally precise if the exact positioning of the tumor to be treated is repeatedly checked during treatment.
Gold pins mark the tumor
IGRT (image-guided radiotherapy), an image-controlled radiotherapy, provides a remedy. Tiny gold pencils, so-called "gold marker seeds", are implanted into the patient's prostate before treatment begins. Using the computer tomograph attached to the linear accelerator, it is then possible to make the prostate visible during irradiation and track organ movements using the marker seeds. Positional deviations of the prostate are determined and corrected immediately. This ensures that the prostate and tumor are irradiated with millimeter accuracy,"explains Dr. Weise.
The ultra-modern linear accelerator of the new radiotherapy centre can do even more: In the future, the facility will also enable irradiation with the innovative "Rapid Arc" technology, a further development of intensity-modulated radiotherapy (IMRT). The prostate is irradiated in a single 360-degree rotation of the irradiation head, which moves around the patient once in just two minutes. The shape of the irradiation field and the radiation dose are constantly adapted to the shape and position of the tumour during treatment. This allows for an even more effective and at the same time gentle irradiation of our patients,"summarizes Dr. Weise.