For radiotherapy an isotope is paced in or around canecr site. It is called as:

Ans: A (Brachytherapy) Types of radiotherapy Grainger & Allison's Diagnostic Radiology 6thfl 737-44External beam radiotherapy: It refer to any situation where the source of the radiation is located at a distance from the patient & the beam of radiation is then directed towards a defined treatment area. Approximately 85% of all therapeutic radiation exposures are delivered using externa! beam techniques.Conventional external beam radiotherapyThree dimensional conformal radiotherapyIntensity-modulated radiotherapy: In this the intensity of radiation beam is modulated across each treatment beamStereotactic body radiotherapy: The distribution of radiation beam is in 3-dimensions & not in two as in traditional radiotherapyBrachytherapy: 11 refers to situation in which a radioisotope is placed onto or inside the patient. The source can be placed into the target tissues or tumour itself such as prostate or breastfinterstitial brachytherapy, into a body cavity such as the uterine cavity, oesophagus or bronchus (intracavity/ intraluminal brachytherapy) otonto the skin surface to treat a cutaneous malignancyParticle therapy: Also known as Hadron therapy. It is an external beam radiation technique in which highly energetic particle such as protons, neutrons or positive ions are directed at the tumorTeletherapy: Treatment in which the radiation source is at a distance from the body. Linear accelerators & cobalt machines are used in teletherapy. Also called external beam therapy"-'"Brachy therapy: A type of radiation therapy is which radioactive materials are placed in direct contact with the tissue being treated. Broadly it is of two types- interstitial or intracavity"- Review of Radiology by Sumer Sethi 6thfl 76Types of brachytherapyMold brachytherapy*3 Superficial tumours can be treated using sealed sources placed close to the skinInterstitial brachytherapy13 Here the sources are inserted into tissueIntracavitary brachytherapy13 places the sources inside a pre-existing body cavityIntravascular brachytherapy places a catheter inside the vasculature through which sources are sent and returnedElectronic brachytherapy places a miniature low energy (< SOkVp) x-ray tube source into a pre-positioned applicator within body/tumor cavities to rapidly deliver high doses to target tissues while maintaining low doses to distant non-target tissuesTHERAPEUTIC RADIATION Harrison 19thTherapeutic radiation is delivered in three ways: (1) teletherapy, with focused beams of radiation generated at a distance and aimed at the tumor within the patient; (2)brachytherapy, with encapsulated sources of radiation implanted directly into or adjacent to tumor tissues; and (3)systemic therapy, with radionuclides administered, for example, intravenously but targeted by some means to a tumor site.Teletherapy with x-ray or gamma-ray photons is the most commonly used form of radiation therapy.