The department of radiology and radiation medicine

Historically, the three main divisions of

radiation therapy are external beam radiation

therapy (EBRT or XRT) or teletherapy,

brachytherapy or sealed source radiation

therapy, and systemic radioisotope therapy

or unsealed source radiotherapy. The

differences relate to the position of the

radiation source; external is outside the body,

brachytherapy uses sealed radioactive sources

placed precisely in the area under treatment,

and systemic radioisotopes are given by

infusion or oral ingestion.

Brachytherapy can use temporary or

permanent placement of radioactive sources.

The temporary sources are usually placed by

a technique called afterloading. In

afterloading a hollow tube or applicator is

placed surgically in the organ to be treated,

and the sources are loaded into the applicator

after the applicator is implanted. This

minimizes radiation exposure to health care

personnel.

Particle therapy is a special case of external

beam radiation therapy where the particles

are protons or heavier ions. Intraoperative

radiation therapy or IORT is a special type of

radiation therapy that is delivered

immediately after surgical removal of the

cancer. This method has been employed in

breast cancer (TARGeted Introperative

radiation therapy or TARGIT), brain tumors

and rectal cancers.

Conventional external beam radiation therapy

Conventional external beam radiationtherapy (2DXRT) is delivered via two-dimensional beams using kilovoltage therapyx-ray units or medical linear acceleratorswhich generate high energy x-rays.

2DXRT mainly consists of a single beam ofradiation delivered to the patient from severaldirections: often front or back, and bothsides.

Conventional refers to the way the treatment

is planned or simulated on a specially calibrated

diagnostic x-ray machine known as a simulator

because it recreates the linear accelerator actions (or

sometimes by eye), and to the usually well-

established arrangements of the radiation beams to

achieve a desiredplan. The aim of simulation is to

accurately target or localize the volume which is to

be treated. This technique is well established and is

generally quick and reliable. The worry is that some

high-dose treatments may be limited by the

radiation toxicity capacity of healthy tissues which

lay close to the target tumor volume.

An example of this problem is seen in radiationof the prostate gland, where the sensitivity ofthe adjacent rectum limited the dose whichcould be safely prescribed using 2DXRTplanning to such an extent that tumor controlmay not be easily achievable. Prior to theinvention of the CT, physicians and physicistshad limited knowledge about the true radiationdosage delivered to both cancerous andhealthy tissue. For this reason, 3-dimensionalconformal radiation therapy is becoming thestandard treatment for a number of tumor sites.More recently other forms of imaging are usedincluding MRI, PET, SPECT and Ultrasound.

Stereotactic radiation is a specialized type of

external beam radiation therapy. It uses

focused radiation beams targeting a well-

defined tumor using extremely detailed

imaging scans. Radiation oncologists perform

stereotactic treatments, often with the help of

a neurosurgeon for tumors in the brain or

spine.

There are two types of stereotactic radiation:

Stereotactic radiosurgery (SRS) is

when doctors use a single or several

stereotactic radiation treatments of the brain

or spine.

Stereotactic body radiation

therapy (SBRT) refers to one or several

stereotactic radiation treatments with the

body, such as the lungs.

Some doctors say an advantage to stereotactic

treatments is that they deliver the right

amount of radiation to the cancer in a shorter

amount of time than traditional treatments,

which can often take six to 11 weeks. Plus

treatments are given with extreme accuracy,

which should limit the effect of the radiation

on healthy tissues. One problem with

stereotactic treatments is that they are only

suitable for certain small tumors.

Stereotactic treatments can be confusing

because many hospitals call the treatments by

the name of the manufacturer rather than

calling it SRS or SBRT. Brand names for

these treatments include

Axesse, Cyberknife, Gamma Knife, Novalis,

Primatom, Synergy, X-

Knife, TomoTherapy, Trilogy and Truebeam.

This list changes as equipment manufacturers

continue to develop new, specialized

technologies to treat cancers.

Despite its name, SRS is not a surgical

procedure.

The technique provides high-precision radiation

delivery to the tumor large dose by passing

healthy tissue located near. This distinguishes

SRH of standard radiation therapy.

Methods of three-dimensional visualization and localization, to determine the exact coordinates of the tumor or target organ.

Accessories for immobilization and careful positioning of the patient.

Clearly focused beams of gamma rays or X-rays that converge on the tumor or other pathological formation.

Methods of conducting radiotherapy under visual control, meaning the position of the tumor tracking during radiation cycle, thus increasing the accuracy and effectiveness of treatment

Typically, stereotactic radiosurgical intervention

carried out simultaneously. However, some experts

recommend several sessions of radiotherapy,

especially in larger tumors 3-4 cm in diameter.

This method of appointment 2-5 treatment sessions

is called fractionated stereotactic radiotherapy.

SRS and extracranial stereotactic intervention are an important alternative to open surgical procedures, especially for patients with contraindications. In addition, stereotactic intervention are indicated in tumors that are:

Located in hard areas for the surgeon.

Located next to vital organs.

Changes its position at physiological movements such as breathing

Radiosurgical procedures used in the following cases:

For the treatment of many brain tumors, including: benign and malignant tumors primary and metastatic lesions single and multiple tumors residual tumor foci after surgery intracranial lesions and tumors of the skull base and

orbit to treat arteriovenous malformations (AVM), which

represent an accumulation of modified or extended form blood vessels. AVM impair the normal blood flow to nerve tissue and prone to bleeding.

For the treatment of other neurological conditions and diseases

The treatment does not remove the tumor and only damages the DNA of tumor cells. As a result, cells lose their ability to reproduce. After the intervention radiosurgical tumor size reduced gradually over 1.5-2 years. This malignant and metastatic foci decreased even faster, sometimes for 2-3 months. If SRH is used for arteriovenous malformation, that for several years a gradual thickening of the vessel wall is observed and its lumen is complete close.

Gamma Knife is for radiation target organs used

192 or 201 clearly focused beam of gamma rays.

Gamma Knife treatment is perfect for small or

medium-sized intracranial injuries.

Linear accelerators - devices that are widely

distributed around the world and used to deliver

high-energy X-rays (photon beam). Suitable for

treating large tumor foci. The procedure can be

performed once or in several stages.

The realization stereotaxic surgery requires a

team approach. The group attending staff include:

oncologist, radiologist, medical physicist,

dosimetrist, radiologist / technician and nurse of

radiology department.

In most cases, after radiosurgical treatment return to normal

life is possible in 1-2 days.

Side effects are determined by the area of the body affected

by radiation. These include:

Hair loss in region of exposure

Ulceration of the mucous membrane of the mouth and

difficulty swallowing

Loss of appetite and indigestion

Diarrhea

Nausea and vomiting

Headaches

Disorder of urination

Radiosurgical treatment using the Gamma Knife system consists of four stages:

Setting retaining frame on the patient's head

Visualization of the tumor position

Treatment plan using a computer program

The procedure of radiation.

Stereotactic Radiosurgical procedure usually can be held ambulatory. However, it may be needed a short-term hospitalization.

About the supporting of the patient back home doctor must notify in advance.

For 12 hours before the procedure it is needed to stop taking food and liquids. It is also important to know your doctor about limitations in taking drugs.