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Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled Oncology is the branch of medicine that studies Tumors ( Cancer) and seeks to understand their development diagnosis treatment and prevention Malignant (from the Latin roots mal- = "bad" and -genus = "born" is a medical term used to describe a severe and progressively worsening disease The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Radiology is the medical specialty directing Medical imaging technologies to diagnose and treat diseases Medical imaging refers to the techniques and processes used to create Images of the human body (or parts thereof for clinical purposes ( Medical procedures seeking to Diagnosis is the identification by Process of elimination, of the nature of anything Radiotherapy may be used for curative or adjuvant cancer treatment. Adjuvant chemotherapy is a term used to describe the role of Chemotherapy relative to other cancer treatments It is used as palliative treatment (where cure is not possible and the aim is for local disease control or symptomatic relief) or as therapeutic treatment (where the therapy has survival benefit and it can be curative). Palliative care (from Latin palliare to cloak is any form of medical care or treatment that concentrates on reducing the severity of Disease Symptoms Total body irradiation (TBI) is a radiotherapy technique used to prepare the body to receive a bone marrow transplant. Total body irradiation (TBI is a form of Radiotherapy used primarily as part of the preparative regimen for haematopoietic stem cell (or bone marrow transplantation Radiotherapy has several applications in non-malignant conditions, such as the treatment of trigeminal neuralgia, severe thyroid eye disease, pterygium, pigmented villonodular synovitis, prevention of keloid scar growth, and prevention of heterotopic ossification. Trigeminal neuralgia (TN, or Tic Doloureux, (also known as prosopalgia is a neuropathic disorder of the Trigeminal nerve that causes episodes of intense Graves' ophthalmopathy, also known as Graves' thyroid-associated or dysthyroid orbitopathy or exophthalmos, is an Pterygium refers to any winglike triangular membrane occurring in the Neck, eyes Knees elbows Ankles Pigmented villonodular synovitis (PVNS is a rare Benign condition that affects the Synovium of Joints, Bursae, and tendon sheaths A keloid is a type of Hypertrophic scar with mainly type I and some type III collagen which results in an overgrowth of tissue at the site of a healed skin injury Heterotopic ossification (HO is the process by which Trabecular bone forms outside of the Skeleton. The use of radiotherapy in non-malignant conditions is limited partly by worries about the risk of radiation-induced cancers.

Radiotherapy is used for the treatment of malignant tumors (cancer), and may be used as the primary therapy. See also Cancer A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells (termed neoplastic Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled It is also common to combine radiotherapy with surgery, chemotherapy, hormone therapy or some mixture of the three. Surgery (from the χειρουργική cheirourgikē, via chirurgiae meaning "hand work" is a medical specialty that uses operative manual and instrumental Chemotherapy, in its most general sense refers to treatment of disease by chemicals that kill cells specifically those of micro-organisms or Cancer. Hormonal therapy is one of the major modalities of medical treatment for cancer others being cytotoxic chemotherapy and Targeted therapy (biotherapeutics Most common cancer types can be treated with radiotherapy in some way. The precise treatment intent (curative, adjuvant, neoadjuvant, therapeutic, or palliative) will depend on the tumour type, location, and stage, as well as the general health of the patient. Neoadjuvant chemotherapy refers to Drug treatment given to people with Cancer prior to surgery Palliative care (from Latin palliare to cloak is any form of medical care or treatment that concentrates on reducing the severity of Disease Symptoms

Radiation therapy is commonly applied to the cancerous tumour. The radiation fields may also include the draining lymph nodes if they are clinically or radiologically involved with tumour, or if there is thought to be a risk of subclinical malignant spread. It is necessary to include a margin of normal tissue around the tumour to allow for uncertainties in daily set-up and internal tumor motion. These uncertainties can be caused by internal movement (for example, respiration and bladder filling) and movement of external skin marks relative to the tumour position.

To spare normal tissues (such as skin or organs which radiation must pass through in order to treat the tumour), shaped radiation beams are aimed from several angles of exposure to intersect at the tumour, providing a much larger absorbed dose there than in the surrounding, healthy tissue. Absorbed dose (also known as total ionizing dose, TID is a measure of the energy deposited in a medium by Ionizing radiation.

Contents

Side effects

Radiation therapy is in itself painless. Many low-dose palliative treatments (for example, radiotherapy to bony metastases) cause minimal or no side effects. Palliative care (from Latin palliare to cloak is any form of medical care or treatment that concentrates on reducing the severity of Disease Symptoms Metastasis ( Greek: displacement μετά=next + στάσις=placement, plural metastases) sometimes abbreviated mets, Treatment to higher doses causes varying side effects during treatment (acute side effects), in the months or years following treatment (long-term side effects), or after re-treatment (cumulative side effects). The nature, severity, and longevity of side effects depends on the organs that receive the radiation, the treatment itself (type of radiation, dose, fractionation, concurrent chemotherapy), and the patient.

Most side effects are predictable and expected. Side effects from radiation are usually limited to the area of the patients body that is under treatment. One of the aims of modern radiotherapy is to reduce side effects to a minimum, and to help the patient to understand and to deal with those side effects which are unavoidable.

Acute side effects

Damage, possibly severe, to epithelial surfaces (skin, oral, pharyngeal and bowel mucosa, urothelium)
The rates of onset and of recovery depend on the rate of turnover of the epithelial cells. The urothelium is the tissue layer that lines much of the Urinary tract, including the Renal pelvis, the Ureters the bladder, and In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body Typically the skin starts to become pink and sore several weeks into treatment. The reaction may become more severe during the treatment and for up to about one week following the end of radiotherapy, and the skin may break down. Although this moist desquamation is uncomfortable, recovery is usually quick. Moist desquamation is a description of the clinical pattern seen in Radiotherapy where the Skin thins and then starts to weep because of loss of integrity of the epithelial Skin reactions tend to be worse in areas where there are natural folds in the skin, such as underneath the female breast, behind the ear, and in the groin.
Similarly, the lining of the mouth, throat, esophagus, and bowel may be damaged by radiation. If the head and neck area is treated, temporary soreness and ulceration commonly occur in the mouth and throat. If severe, this can affect swallowing, and the patient may need painkillers and nutritional support. The esophagus can also become sore if it is treated directly, or if, as commonly occurs, it receives a dose of collateral radiation during treatment of lung cancer.
The lower bowel may be treated directly with radiation (treatment of rectal or anal cancer) or be exposed by radiotherapy to other pelvic structures (prostate, bladder, female genital tract). Typical symptoms are soreness, diarrhoea, and nausea.
Swelling (edema or Oedema)
As part of the general inflammation that occurs, swelling of soft tissues may cause problems during radiotherapy. This is a concern during treatment of brain tumours and brain metastases, especially where there is pre-existing raised intracranial pressure or where the tumour is causing near-total obstruction of a lumen (e. Intracranial pressure, ( ICP) is the pressure exerted by the Cranium on the Brain tissue Cerebrospinal fluid (CSF and the brain's circulating A lumen (Lat lūmen, an opening or light (pl lumina is the inside space or lining of a tubular structure such as an artery or intestine g. , trachea or main bronchus). The traceartes, or windpipe, is a tube that has an inner diameter of about 20-25 mm and a length of about 10-16 cm in humans A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the Respiratory tract that conducts air into the Lungs No Gas Surgical intervention may be considered prior to treatment with radiation. If surgery is deemed unnecessary or inappropriate, the patient may receive steroids during radiotherapy to reduce swelling. A steroid is a Terpenoid Lipid characterized by a Carbon skeleton with four fused rings generally arranged in a 6-6-6-5 fashion
Infertility
The gonads (ovaries and testicles) are very sensitive to radiation. The gonad is the organ that makes Gametes The gonads in males are the Testes and the gonads in Females are the Ovaries. They may be unable to produce gametes following direct exposure to most normal treatment doses of radiation. A gamete (from Ancient Greek γαμέτης; translated gamete = wife gametes = husband is a cell that fuses with another gamete Treatment planning for all body sites is designed to minimize, if not completely exclude dose to the gonads if they are not the primary area of treatment.
Generalized fatigue

Medium and long-term side effects

These depend on the tissue that received the treatment; they may be minimal.

Fibrosis
Tissues which have been irradiated tend to become less elastic over time due to a diffuse scarring process. Fibrosis is the formation or development of excess fibrous Connective tissue in an organ or tissue as a reparative or reactive process as opposed to a formation of Fibrous
Hair loss
This may be most pronounced in patients who have received radiotherapy to the brain. Unlike the hair loss seen with chemotherapy, radiation-induced hair loss is more likely to be permanent, but is also more likely to be limited to the area treated by the radiation.
Dryness
The salivary glands and tear glands have a radiation tolerance of about 30 Gy in 2 Gy fractions, a dose which is exceeded by most radical head and neck cancer treatments. The gray (symbol Gy is the SI unit of absorbed radiation dose. Dry mouth (xerostomia) and dry eyes (xerophthalmia) can become irritating long-term problems and severely reduce the patient's quality of life. Xerostomia is the medical term for a dry mouth due to a lack of Saliva. Xerophthalmia ( Greek for dry eyes) is a medical condition in which the Eye fails to produce Tears. Similarly, sweat glands in treated skin (such as the armpit) tend to stop working, and the naturally moist vaginal mucosa is often dry following pelvic irradiation. The skin contains two different groups of sweat glands: Apocrine sweat glands and Merocrine sweat glands. The axilla (or armpit, underarm, or oxter) is the area on the human body directly under the joint where the Arm connects to the Shoulder The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin covered in Epithelium, which are involved in
Cancer
Radiation is a potential cause of cancer, and secondary malignancies are seen in a very small minority of patients, generally many years after they have received a course of radiation treatment. In the vast majority of cases, this risk is greatly outweighed by the reduction in risk conferred by treating the primary cancer.

Cumulative side effects

Cumulative effects from this process should not be confused with long-term effects—when short-term effects have disappeared and long-term effects are subclinical, reirradiation can still be problematic. [1]

Dose

The amount of radiation used in radiation therapy is measured in gray (Gy), and varies depending on the type and stage of cancer being treated. The gray (symbol Gy is the SI unit of absorbed radiation dose. For curative (radical) cases, the typical dose for a solid epithelial tumor ranges from 60 to 80 Gy, while lymphoma tumors are treated with 20 to 40 Gy.

Preventative (adjuvant) doses are typically around 45 - 60 Gy in 1. 8 - 2 Gy fractions (for Breast, Head and Neck cancers respectively. ) Many other factors are considered by radiation oncologists when selecting a dose, including whether the patient is receiving chemotherapy, whether radiation therapy is being administered before or after surgery, and the degree of success of surgery. A radiation oncologist is a doctor who specializes in the treatment of Cancer patients using radiation as the main modality of treatment

Fractionation

The total dose is fractionated (spread out over time) in order to give normal cells time to recover. Fractionation regimes are highly individualised between different radiotherapy centres and even between individual doctors. In the USA, Australia, and Europe, the typical fractionation schedule for adults is 1. 8 to 2 Gy per day, five days a week. In the northern United Kingdom, fractions are more commonly 2. 67 to 2. 75 Gy per day, which eases the burden on thinly spread resources in the National Health Service. The National Health Service is the name commonly used to refer to the four Publicly-funded healthcare systems of the United Kingdom collectively or individually (although For children, a typical fraction is 1. 5 to 1. 7 Gy per day, reducing the chance and severity of late-onset side effects.

In some cases, two fractions per day are used near the end of a course of treatment. This schedule, known as a concomitant boost regimen or hyperfractionation, is used on tumors that regenerate more quickly when they are smaller. In particular, tumors in the head and neck demonstrate this behavior.

One of the best-known alternative fractionation schedules is Continuous Hyperfractionated Accelerated Radiotherapy (CHART). CHART, used to treat lung cancer, consists of three smaller fractions per day. Although reasonably successful, CHART can be a strain on radiation therapy departments.

Implants can be fractionated over minutes or hours, or they can be permanent seeds which slowly deliver radiation until they become inactive.

Mechanism of action

Radiation therapy works by damaging the DNA of cells. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known The damage is caused by a photon, electron, proton, neutron, or ion beam directly or indirectly ionizing the atoms which make up the DNA chain. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Indirect ionization happens as a result of the ionization of water, forming free radicals, notably hydroxyl radicals, which then damage the DNA. Ionization is the physical process of converting an Atom or Molecule into an Ion by adding or removing charged particles such as Electrons In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell Hydroxyl in Chemistry stands for a molecule consisting of an Oxygen atom and a Hydrogen atom connected by a Covalent bond. In the most common forms of radiation therapy, most of the radiation effect is through free radicals. Because cells have mechanisms for repairing DNA damage, breaking the DNA on both strands proves to be the most significant technique in modifying cell characteristics. Because cancer cells generally are undifferentiated and stem cell-like, they reproduce more, and have a diminished ability to repair sub-lethal damage compared to most healthy differentiated cells. Stem cells are cells found in most if not all multi-cellular Organisms. In Developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized Cell type. The DNA damage is inherited through cell division, accumulating damage to the cancer cells, causing them to die or reproduce more slowly. Proton radiotherapy works by sending protons with varying kinetic energy to precisely stop at the tumor. The kinetic energy of an object is the extra Energy which it possesses due to its motion

One of the major limitations of radiotherapy is that the cells of solid tumors become deficient in oxygen. This is because solid tumours usually outgrow their blood supply, causing a low-oxygen state known as hypoxia. Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate The more hypoxic the tumours are the more resistant they are to the effects of radiation because oxygen makes the radiation damage to DNA permanent. Much research has been devoted to overcoming this problem including the use of high pressure oxygen tanks, blood substitutes that carry increased oxygen, hypoxic cell radiosensitizers such as misonidazole and metronidazole, and hypoxic cytotoxins, such as tirapazamine. Metronidazole ( INN) (mɛtrəˈnaɪdəzoʊl is a Nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible Tirapazamine (SR-4233 is an experimental anticancer drug that is activated to a toxic radical only at very low levels of Oxygen ( hypoxia) There is also interest in the fact that high-LET (linear energy transfer) particles such as carbon or neon ions may have an antitumour effect which is independent of tumour hypoxia. Linear energy transfer (LET is a measure of the Energy transferred to material as an ionizing particle travels through it

History of radiation therapy

Radiation therapy has been in use as a cancer treatment for more than 100 years, with its earliest roots traced from the discovery of x-rays in 1895. [2] The concept of therapeutic radiation was invented by German physicist Wilhelm Conrad Röntgen when he discovered that the x-ray was a powerful and effective tool with which to treat cancer. Wilhelm Conrad Röntgen (27 March 1845 &ndash 10 February 1923 was a German physicist, who on 8 November 1895 produced and detected Electromagnetic

The field of radiation therapy began to grow in the early 1900s largely due to the groundbreaking work of Nobel Prize-winning scientist Marie Curie, who discovered the radioactive elements polonium and radium. The Nobel Prize (Nobelpriset (Nobelprisen is a Swedish prize established in the 1895 will of Swedish chemist Alfred Nobel; it was first awarded in Peace, Literature Polonium (pəˈloʊniəm is a Chemical element with the symbol Po and Atomic number 84 discovered in 1898 by Marie and Pierre Curie Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 This began a new era in medical treatment and research. [2] Radium was used in various forms until the mid-1900s when cobalt and caesium units came into use. Cobalt (ˈkoʊbɒlt is a hard lustrous silver-grey Metal, a Chemical element with symbol Co. Caesium or cesium (ˈsiːziəm is the Chemical element with the symbol Cs and Atomic number 55 Medical linear accelerators have been developed since the late 1940s.

With Godfrey Hounsfield’s discovery of computed tomography (CT), three-dimensional planning became a possibility and created a shift from 2-D to 3-D radiation delivery; physicians and physics were no longer limited because CT-based planning allowed physicians to directly measure the dose delivered to the patient's anatomy based on axial tomographical images. Sir Godfrey Newbold Hounsfield CBE FRS, ( 28 August 1919 &ndash 12 August 2004) was an English Electrical engineer Computed tomography (CT is a Medical imaging method employing Tomography. Orthovoltage and cobalt units have largely been replaced by megavoltage linear accelerators, useful for their penetrating energies and lack of physical radiation source.

In the last few decades, the advent of new imaging technologies, e. g. , magnetic resonance imaging (MRI) in the 1970s and positron emission tomography (PET) in the 1980s, as well as new radiation delivery and visualization products, e. Positron emission tomography ( PET) is a Nuclear medicine imaging technique which produces a three-dimensional image or map of functional processes in the g. , digital linear accelerator, image fusion has moved radiation therapy from 3-D conformal to IMRT and eventually to IGRT (4-D) in the near future. In Computer vision, Multisensor Image Fusion is the process of combining relevant information from two or more images These advances have resulted in better treatment outcomes and less side effects. Now 70% of cancer patients receive radiation therapy as part of their cancer treatment.


Types of radiation therapy

Historically, the three main divisions of radiotherapy are external beam radiotherapy (EBRT or XBRT) or teletherapy, brachytherapy or sealed source radiotherapy and unsealed source radiotherapy. External beam radiotherapy otherwise known as teletherapy, is the most frequently used form of Radiotherapy. Brachytherapy (from the Greek brachy, meaning "short" also known as sealed source radiotherapy or endocurietherapy, is a form of Unsealed source radiotherapy relates to the use of soluble forms of radioactive substances which are administered to the body by injection or ingestion The differences relate to the position of the radiation source; external is outside the body, while sealed and unsealed source radiotherapy has radioactive material delivered internally. Brachytherapy sealed sources are usually extracted later, while unsealed sources may be administered by injection or ingestion. Proton therapy is a special case of external beam radiotherapy where the particles are protons. Proton therapy is a type of Particle therapy which utilizes a beam of Protons to irradiate diseased tissue most often in the treatment of cancer The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Introperative radiotherapy[3] is a special type of radiotherapy that is delivered immediately after surgical removal of the cancer. This method has been employed in breast cancer (TARGeted Introperative radioTherapy), brain tumours and rectal cancers.

Conventional external beam radiotherapy

Conventional external beam radiotherapy (2DXRT) is delivered via two-dimensional beams using linear accelerator machines. 2DXRT mainly consists of a single beam of radiation delivered to the patient from several directions: often front or back, and both sides. 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 desired plan. 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 radiation of the prostate gland, where the sensitivity of the adjacent rectum limits the dose which can be safely prescribed to such an extent that tumor control may not be easily achievable. Previous to the invention of the CT, physicians and physicists had limited knowledge about the true radiation dosage delivered to both cancerous and healthy tissue. For this reason, 3-dimensional conformal radiotherapy is becoming the standard treatment for a number of tumor sites.

Virtual simulation, 3-dimensional conformal radiotherapy, and intensity-modulated radiotherapy

The planning of radiotherapy treatment has been revolutionized by the ability to delineate tumors and adjacent normal structures in three dimensions using specialized CT and/or MRI scanners and planning software. [4] Virtual simulation, the most basic form of planning, allows more accurate placement of radiation beams than is possible using conventional X-rays, where soft-tissue structures are often difficult to assess and normal tissues difficult to protect.

An enhancement of virtual simulation is 3-Dimensional Conformal Radiotherapy (3DCRT), in which the profile of each radiation beam is shaped to fit the profile of the target from a beam's eye view (BEV) using a multileaf collimator (MLC) and a variable number of beams. Beam's Eye View (or BEV) is an imaging technique used in Radiation therapy for the quality assurance and planning of External Beam Radiation Therapy treatments A multileaf collimator ( MLC) is a device made up of individual 'leaves' of a high atomic numbered material usually Tungsten, that can move independently in and out When the treatment volume conforms to the shape of the tumour, the relative toxicity of radiation to the surrounding normal tissues is reduced, allowing a higher dose of radiation to be delivered to the tumor than conventional techniques would allow.

Intensity-Modulated Radiation Therapy (IMRT) is an advanced type of high-precision radiation that is the next generation of 3DCRT. [5]IMRT also improves the ability to conform the treatment volume to concave tumor shapes, for example when the tumor is wrapped around a vulnerable structure such as the spinal cord or a major organ or blood vessel. Computer-controlled x-ray accelerators distribute precise radiation doses to malignant tumors or specific areas within the tumor. The pattern of radiation delivery is determined using highly-tailored computing applications to perform optimization and treatment simulation (Treatment Planning). In Mathematics, the term optimization, or mathematical programming, refers to the study of problems in which one seeks to minimize or maximize a real function In Radiotherapy, Treatment Planning is the process in which a team consisting of radiation Oncologists, medical radiation physicists and dosimetrists plan the appropriate The radiation dose is consistent with the 3-D shape of the tumor by controlling, or modulating, the radiation beam’s intensity. The radiation dose intensity is elevated near the gross tumor volume while radiation among the neighboring normal tissue is decreased or avoided completely. The customized radiation dose is intended to maximize tumor dose while simultaneously protecting the surrounding normal tissue. Because sparing healthy tissue as compared with conventional radiation therapy techniques (2DXRT and 3DCRT). This in turn results in better tumor targeting, lessened side effects, and improved treatment outcomes than even 3DCRT.

3DCRT is still used extensively for many body sites but the use of IMRT is growing in more complicated body sites such as CNS, head and neck, prostate, breast and lung. Unfortunately, IMRT is limited by its need for additional time from experienced medical personnel. This is because physicians must manually delineate the tumors one CT image at a time through the entire disease site which can take much longer than 3DCRT preparation. Then, medical physicists and dosimetrists must be engaged to create a viable treatment plan. Also, the IMRT technology has only been used commercially since the late 1990s even at the most advanced cancer centers, so radiation oncologists who did not learn it as part of their residency program must find additional sources of education before implementing IMRT.

Proof of improved survival benefit from either of these two techniques over conventional radiotherapy (2DXRT) is growing for many tumor sites, but the ability to reduce toxicity is generally accepted. Both techniques enable dose escalation, potentially increasing usefulness. There has been some concern, particularly with 3DCRT, about increased exposure of normal tissue to radiation and the consequent potential for secondary malignancy. Overconfidence in the accuracy of imaging may increase the chance of missing lesions that are invisible on the planning scans (and therefore not included in the treatment plan) or that move between or during a treatment (for example, due to respiration or inadequate patient immobilization). New techniques are being developed to better control this uncertainty—for example, real-time imaging combined with real-time adjustment of the therapeutic beams. This new technology is called image-guided radiation therapy (IGRT) or four-dimensional radiotherapy. Image-guided radiation therapy (IGRT is the process of frequent two and three-dimensional imaging during a course of radiation treatment used to direct radiation therapy utilizing the Image-guided radiation therapy (IGRT is the process of frequent two and three-dimensional imaging during a course of radiation treatment used to direct radiation therapy utilizing the

Radioisotope Therapy (RIT)

Radiotherapy can also be delivered through infusion (into the bloodstream) or ingestion. In Pharmacology and Toxicology, a route Examples are the infusion of metaiodobenzylguanidine (MIBG) to treat neuroblastoma, of oral iodine-131 to treat thyroid cancer or thyrotoxicosis, and of hormone-bound lutetium-177 and yttrium-90 to treat neuroendocrine tumors (peptide receptor radionuclide therapy). Iobenguane, also known as metaiodobenzylguanidine or mIBG, is a Radiopharmaceutical. Neuroblastoma is the most common extracranial solid Cancer in childhood and the most common cancer in infancy with an annual incidence of about 650 new cases per year in the Iodine-131 (131I, also called radioiodine, is a Radioisotope of Iodine which has medical and pharmaceutical uses Thyroid cancer refers to any of four kinds of malignant Tumors of the Thyroid gland papillary, follicular, medullary or Hyperthyroidism is the term for overactive tissue within the Thyroid gland resulting in overproduction and thus an excess of circulating free thyroid hormones Thyroxine Lutetium (ljuːˈtiːʃiəm is a Chemical element with the symbol Lu and Atomic number 71 Yttrium (ˈɪtriəm is a Chemical element with symbol Y and Atomic number 39 Neuroendocrine tumors, or more properly gastro-entero-pancreatic or gastroenteropancreatic neuroendocrine Tumors ( GEP-NETs) are cancers of Another example is the injection of radioactive glass or resin microspheres into the hepatic artery to radioembolize liver tumors or liver metastases. The hepatic artery proper (also proper hepatic artery) arises from the Common hepatic artery and runs alongside the Portal vein and the Common bile

In 2002, the United States Food and Drug Administration (FDA) approved Ibritumomab tiuxetan (Zevalin), which is a monoclonal antibody anti-CD20 conjugated to a molecule of Yttrium-90. Ibritumomab tiuxetan, also sold under the trade name Zevalin, is a monoclonal antibody Radioimmunotherapy treatment for some forms of B cell Monoclonal antibodies ( mAb or moAb) are monospecific antibodies that are identical because they are produced by one type of immune cell CD20 is a non- Glycosylated phosphoprotein expressed on the surface of all mature B-cells. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by [6] In 2003, the FDA approved Tositumomab Iodine-131 (Bexxar), which conjugates a molecule of Iodine-131 to the monoclonal antibody anti-CD20. Tositumomab is a Monoclonal antibody derived from immortalized mouse cells Iodine-131 (131I, also called radioiodine, is a Radioisotope of Iodine which has medical and pharmaceutical uses In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Iodine-131 (131I, also called radioiodine, is a Radioisotope of Iodine which has medical and pharmaceutical uses Monoclonal antibodies ( mAb or moAb) are monospecific antibodies that are identical because they are produced by one type of immune cell CD20 is a non- Glycosylated phosphoprotein expressed on the surface of all mature B-cells. [7] These medications were the first agents of what is known as radioimmunotherapy, and they were approved for the treatment of refractory non-Hodgkins lymphoma. Radio immunotherapy ( RIT) utilizes an Antibody labeled with a Radionuclide to deliver cytotoxic radiation to a target cell The non-Hodgkin lymphomas are a diverse group of hematologic cancers which encompass any Lymphoma other than Hodgkin lymphoma.

References

Notes

  1. ^ Nieder C, Milas L, Ang KK (2000). "Tissue tolerance to reirradiation. ". Semin Radiat Oncol 10 (3): 200-9. doi:10.1053/srao.2000.6593. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 11034631.  
  2. ^ a b University of Alabama at Birmingham Comprehensive Cancer Center, History of Radiation Oncology.
  3. ^ Vaidya J. TARGIT (TARGeted Intraoperative radioTherapy). Retrieved on 2007-03-11. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1425 BC - Thutmose III, Pharaoh of Egypt, dies (according to the Low Chronology of the 18th Dynasty
  4. ^ Bucci M, Bevan A, Roach M (2005). "Advances in radiation therapy: conventional to 3D, to IMRT, to 4D, and beyond. ". CA Cancer J Clin 55 (2): 117-34. PMID 15761080.  Full text
  5. ^ Galvin, JM; Ezzel, G; Eisbrauch, A; Yu, C; Butler, B; Xiao, Y; Rosen, I; Rosenman, J; et al. (2004), “Implementing IMRT in clinical practice: a joint document of the American Society for Therapeutic Radiology and Oncology and the American Association of Physicists in Medicine. ”, Int J Radiat Oncol BiolPhys. 58 (5): 1616-34 
  6. ^ Fda Approves First Radiopharmaceutical Product To Treat Non-Hodgkin’S Lymphoma
  7. ^ Tositumomab and Iodine I 131 Tositumomab - Product Approval Information - Licensing Action

External links

Dictionary

radiation therapy

-noun

  1. (medicine) the use of ionizing radiation to treat disease, especially cancer
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