Different types of<unk>  can be defined according to (1) the placement of the radiation sources in the target treatment area, (2) the rate or ‘intensity’ of the irradiation dose delivered to the tumour, and (3) the duration of dose delivery. Source placement The two main types of<unk>  treatment in terms of the placement of the radioactive source are interstitial and contact. In the case of interstitial<unk> , the sources are placed directly in the target tissue of the affected site, such as the prostate or breast. Contact<unk>  involves placement of the radiation source in a space next to the target tissue. This space may be a body cavity (intracavitary<unk>  such as the cervix, uterus or vagina; a body lumen (intraluminal<unk>  such as the trachea or oesophagus; or externally (surface<unk>  such as the skin. A radiation source can also be placed in blood vessels (intravascular<unk>  for the treatment of coronary in-stent restenosis. Dose rate The dose rate of<unk>  refers to the level or ‘intensity’ with which the radiation is delivered to the surrounding medium and is expressed in Grays per hour (Gy/h). Low-dose rate (LDR)<unk>  involves implanting radiation sources that emit radiation at a rate of up to 2 Gy·h−1. LDR<unk>  is commonly used for cancers of the oral cavity, oropharynx, sarcomas and prostate cancer Medium-dose rate (MDR)<unk>  is characterized by a medium rate of dose delivery, ranging between 2 Gy·h−1 to 12 Gy·h−1. High-dose rate (HDR)<unk>  is when the rate of dose delivery exceeds 12 Gy·h−1. The most common applications of HDR<unk>  are in tumours of the cervix, esophagus, lungs, breasts and prostate. Most<unk> reatments are performed on an outpatient basis, but this is dependent on the treatment site. Pulsed-dose rate (PDR)<unk>  involves short pulses of radiation, typically once an hour, to simulate the overall rate and effectiveness of LDR treatment. Typical tumour sites treated by PDR<unk>  are gynaecological and head and neck cancers. Duration of dose delivery The placement of radiation sources in the target area can be temporary or permanent. Temporary<unk>  involves placement of radiation sources for a set duration (usually a number of minutes or hours) before being withdrawn. The specific treatment duration will depend on many different factors, including the required rate of dose delivery and the type, size and location of the cancer. In LDR and PDR<unk> , the source typically stays in place up to 24 hours before being removed, while in HDR<unk>  this time is typically a few minutes. Permanent<unk> , also known as seed implantation, involves placing small LDR radioactive seeds or pellets (about the size of a grain of rice) in the tumour or treatment site and leaving them there permanently to gradually decay. Over a period of weeks or months, the level of radiation emitted by the sources will decline to almost zero. The inactive seeds then remain in the treatment site with no lasting effect. Permanent<unk>  is most commonly used in the treatment of prostate cancer.
Brachytherapy
Carboxytherapy
Irradiation
Organotherapy
Trepanning
Microwave thermotherapy
Radiation therapy
Chemoradiotherapy