It is a modern and precise procedure that achieves a tumor eradicating dose escalation as well as an optimal conservation of the surrounding tissue. Brachytherapy is also used successfully in the prophylaxis of re-stenoses in peripheral vessels and coronary arteries. In afterloading technique a 192-Iridium radiation source is applied for a short time, i.e. seconds to minutes by remote control to the organ that is to be irradiated. With this technique gynecological tumors, esophagus, cystic duct, and peripheral vessels are treated.

In interstitial Brachytherapy a 192-Ir radiation source inserted temporarily into applicators that have been implanted into the tissue before, or several 125-Iodine radiation sources with a short half-life are directly and permanently implanted into the tissue. This technique is used to treat prostate, rectum, otolaryngological tumors and sarcomas. In contact therapy a sealed radioactive source or an applicator are brought into contact with an external or internal body surface of the patient.

Brachytherapy can be divided into four main types:

• Surface Applicator or "Mould" brachytherapy. Superficial tumors can be treated using sealed sources placed close to the skin. Dosimetry is often performed with reference to the Manchester system; a rule-based approach designed to ensure that the dose to all parts of the target volume is within 10% of the prescription dose.

• Interstitial brachytherapy. The sources are inserted into tissue using needles with a diameter of about one mm. Either iridium-192 is inserted temporarily into these needles or so-called seeds are permanently implanted. Prostate cancer treatment with Iodine-125 is common for interstitial brachytherapy using seeds

• Intracavitary brachytherapy places the sources inside a natural body cavity. The most common applications of this method are gynecological in nature, although it can also be performed on the nasopharynx.

• Intravascular brachytherapy places a catheter with the sources inside the vasculature. The most common application of this method is the treatment of coronary in-stent restenosis, although the therapy has also been investigated for use in the treatment of peripheral vasculature stenoses.

HDR brachytherapy

High Dose Rate (HDR) brachytherapy is a common brachytherapy method and has been available for more than 25 years now.. Applicators in the form of catheters are arranged, usually according to the Manchester or Paris system. A high dose rate source (Iridium 192 or Cobalt 60) is then temporarily placed in the catheters on the end of a wire by the afterloader machine whilst the patient is isolated in a shielded room. The source dwells in a preplanned position for a preset time before stepping forward along the catheter and repeating, to build up the required dose distribution. The advantage of this treatment over implanting radioactive sources directly is that there is lower staff exposure and the source can be more active due to low staff exposure, thus making treatment times quicker.

LDR brachytherapy

Cancer of the prostate is one of the most frequent cancer types of males and is diagnosed in more than 200.000 new cases in Europe last year. As a standard treatment the prostatectomy, i.e. the surgical removal of the prostate, is performed in most cases. Besides the general operation risk a considerable high risk of post-operative incontinence and impotence exists.

Besides prostatectomy, radiation therapy in form of interstitial brachytherapy is gaining more and more significance in therapy of not yet metastasing prostate carcinoma. During one year, more than 60,000 prostate cancer patients are treated world wide with brachytherapy. Extensive long term studies proof a comparable healing and surviving rate with prostatectomy at a significantly reduced risk of side effects. 

Two different brachytherapeutic methods are available for the treatment of prostate carcinoma.

• The permanent implantation of seeds with Iodine-125 or Palladium-103: LDR Brachytherapy (Low Dose Rate)

• The temporary afterloading implantation with Iridium-192, a radiation source moved in steps through the organ, which is only temporarily applied and removed afterwards: HDR Brachytherapy (High Dose Rate). 

LDR Seed Implantation is suitable for low risk and early stage carcinoma of the prostate, while HDR Brachytherapy is used for a wider range of prostate stages, PSA values, and tumor grades. The components and dosages are modified for those with low, intermediate, or high risk prostate cancer. This treatment can also certainly be used for many tumors which are considered to advanced for radical prostatectomy. As long as there is no obvious spread to distant areas of the body like the bones this treatment can still be considered.

The radiation sources are developing their effect directly in the cancerous tissue, only a small dose burden is exposed to adjacent organs. As the radiation sources are less than one millimeter in diameter, implantation is performed with relatively small applicators.

sonoTECH's strong engagement in this advanced treatment method since several years and close cooperation with leading clinicians and physicists resulted in the development of therapy planning systems setting the pace regarding functionality, planning quality and operability.