Radiation therapy is subdivided into external (tele-) and internal (brachy-) therapy. Brachytherapy (Greek: brachy = short) consists in applying the radioactive source directly into or through the tumour. Conversely, teletherapy, (Greek: tele = long) comprises delivering the radiation externally to the patient's body using a linear accelerator. The advantages of brachytherapy include the high dose local irradiation of the diseased tissue while sparing the contiguous healthy tissue.

One form of brachytherapy of the prostate cancer is the implantation of low radioactive, sealed sources, known as seeds, into the prostate. An urologist or radiooncologist implants these small, low radioactive sources using needles through the perineum. This procedure is performed under ultrasound guidance and can be done ambulatory in only few hours.

 

 

 

 

 

 

 

 

A seed has a length of 4.5 mm and a diameter of 0.8 mm 

 

Depending on the diagnosis, brachytherapy can be applied as monotherapy or in combination with either external beam radiation therapy or hormonal treatment. Usually the isotope I-125 is used. For permanent LDR interstitial brachytherapy, Eckert & Ziegler BEBIG offers the IsoSeed in a loose or stranded form, both containing low activity I-125.