Full-body scan
Encyclopedia
Full-body scan is a scan of the patient's entire body to support the diagnosis
and treatment of illnesses. It may also be known as a full-body CT scan if computed tomography
(CAT
) technology is used, though there are many types of medical imaging technology which can perform full-body scans (see box on bottom of page).
A full-body scan can theoretically catch deadly diseases (e.g. cancer
) in early stages, which can save lives. However in practice, the benefits may not outweigh the risks (see sections below). Thus, controversy arises from the use of full-body scans in the screening
of patients who have not been diagnosed with a disease, or who do not have symptom
s suggestive of a disease,. As with any test that screens for disease, the risks of full-body CT scans need to be weighed against the benefit of identifying a treatable disease at an early stage.
Low-dose CT scanning of the lungs may be done to screen for lung cancer
, but it has showed varied success. CT colography, or virtual colonoscopy
is a CT scan that looks for polyps that may develop into colon cancer. It has shown detection rates for polyps of size greater or equal to 8 mm that are comparable to traditional or "optical" colonoscopy
. One of the downsides of imaging is that although they provide comparable detection rates, they have no inherent capability of treatment. For example, if polyps are found on virtual colonoscopy the next step is to perform a traditional colonoscopy
to remove the polyps; however the initial diagnosis is significantly less invasive.
Other types of scans include heart
, brain
, bone density
, angiogram
and carotid artery
.
Magnetic resonance imaging
(MRI) scans are associated with a lesser radiation risk than CT scans, and are being evaluated for their use in screening.
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
and treatment of illnesses. It may also be known as a full-body CT scan if computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
(CAT
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
) technology is used, though there are many types of medical imaging technology which can perform full-body scans (see box on bottom of page).
Use in preventive screening
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
) in early stages, which can save lives. However in practice, the benefits may not outweigh the risks (see sections below). Thus, controversy arises from the use of full-body scans in the screening
Screening (medicine)
Screening, in medicine, is a strategy used in a population to detect a disease in individuals without signs or symptoms of that disease. Unlike what generally happens in medicine, screening tests are performed on persons without any clinical sign of disease....
of patients who have not been diagnosed with a disease, or who do not have symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
s suggestive of a disease,. As with any test that screens for disease, the risks of full-body CT scans need to be weighed against the benefit of identifying a treatable disease at an early stage.
Health risks
- Compared to most other diagnostic X-rayX-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
procedures, CT scans result in relatively high radiation exposureRadiation exposureThe term radiation exposure commonly has several uses:* Absorption of high-energy ionizing radiation by an object. In living beings a high absorbed dose can lead to radiation poisoning.* Absorption by an object of non-ionizing radiation...
. This exposure may be associated with a very small increase in the possibility of developing cancer later in a person's life. This risk is greatly outweighed by the benefits of diagnostic and therapeutic CT; however is questionable when used on asymptomaticAsymptomaticIn medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...
individuals.
Diagnosis benefits
- Allows a transparent view of the body, which normally is not transparent. Many possible malignancies are discovered with a full-body scan, but these are almost always benign. These may not be related to any disease, and may be benign growths, scar tissueScarScars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...
, or the remnants of previous infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s. CT scanning for other reasons sometimes identifies these "incidentalomaIncidentalomaIn medicine, an incidentaloma is a tumor found by coincidence without clinical symptoms or suspicion. It is a common problem: up to 7% of all patients over 60 may harbor a benign growth, often of the adrenal gland, which is detected when diagnostic imaging is used for the analysis of unrelated...
s".
Other issues
- Low rate of finding disease.
- Confusion regarding "incidentalomas" (see above): It is uncertain how to treat some of them, or if treatment is even necessary.
- Possibly high cost: At a cost of US$United States dollarThe United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
600 to $3000, full-body scans are expensive, and are rarely covered by insurance. However, in December 2007, the IRS stated that full-body scans qualify as deductible medical expenses, without a doctor's referral. This will likely lead employer-sponsored, flexible-spending plans to make the cost of the scans eligible for reimbursement. - May not be able to detect colors, unlike for example a colonoscopyColonoscopyColonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
.
Partial-body scans
Other CT scans may be used in screening for disease in high risk groups. These scans are more localized and are identical to those used in the course of treating a disease, the only difference being that these scans are done before any disease is found.Low-dose CT scanning of the lungs may be done to screen for lung cancer
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
, but it has showed varied success. CT colography, or virtual colonoscopy
Virtual colonoscopy
Virtual colonoscopy is a medical imaging procedure which uses x-rays and computers to produce two- and three-dimensional images of the colon from the lowest part, the rectum, all the way to the lower end of the small intestine and display them on a screen...
is a CT scan that looks for polyps that may develop into colon cancer. It has shown detection rates for polyps of size greater or equal to 8 mm that are comparable to traditional or "optical" colonoscopy
Colonoscopy
Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
. One of the downsides of imaging is that although they provide comparable detection rates, they have no inherent capability of treatment. For example, if polyps are found on virtual colonoscopy the next step is to perform a traditional colonoscopy
Colonoscopy
Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
to remove the polyps; however the initial diagnosis is significantly less invasive.
Other types of scans include heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
, brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
, bone density
Bone density
Bone density is a medical term normally referring to the amount of mineral matter per square centimeter of bones. Bone density is used in clinical medicine as an indirect indicator of osteoporosis and fracture risk.This medical bone density is not the true physical "density" of the bone, which...
, angiogram
Angiogram
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins and the heart chambers...
and carotid artery
Carotid artery
Carotid artery can refer to:* Common carotid artery* External carotid artery* Internal carotid artery...
.
Magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI) scans are associated with a lesser radiation risk than CT scans, and are being evaluated for their use in screening.
In popular culture
- In the episode "Role Model" of the TV show HouseHouse (TV series)House is an American television medical drama that debuted on the Fox network on November 16, 2004. The show's central character is Dr. Gregory House , an unconventional and misanthropic medical genius who heads a team of diagnosticians at the fictional Princeton-Plainsboro Teaching Hospital in...
the lead character Dr. Gregory House refers to full-body scans as "useless" because, in his words, "you could probably scan every one of us and find fifty doo-dads that look like cancer". This issue was revisited in a later episode, "The Social ContractThe Social Contract (House)"The Social Contract" is the seventeenth episode of the fifth season of House. It aired on March 9, 2009.- Plot :The episode starts with an author, Timothy Moore, making a toast to his soon to be best-seller. After the toast, Nick Greenwald, the editor, insults the book by saying how short stories...
", where a full-body scan was successfully used to identify a tumor and diagnose Doege-Potter syndromeDoege-Potter syndromeDoege-Potter syndrome is a paraneoplastic syndrome in which hypoglycemia is associated with the presence of one or more non-islet fibrous tumors in the pleural cavity. The hypoglycemia is the result of the tumors producing insulin-like growth factor 2...
. Then in "Black HoleBlack Hole (House)"Black Hole" is the sixteenth episode of the sixth season of the American medical drama House. It was directed by Greg Yaitanes and written by Lawrence Kaplow. It aired on March 15, 2010....
", House orders a full-body scan over the objections of his team, followed by a different scan on a pineal glandPineal glandThe pineal gland is a small endocrine gland in the vertebrate brain. It produces the serotonin derivative melatonin, a hormone that affects the modulation of wake/sleep patterns and seasonal functions...
.
- In the ScrubsScrubs (TV series)Scrubs is an American medical comedy-drama television series created in 2001 by Bill Lawrence and produced by ABC Studios. The show follows the lives of several employees of the fictional Sacred Heart, a teaching hospital. It features fast-paced screenplay, slapstick, and surreal vignettes...
episode "My Fault", Dr. KelsoBob KelsoRobert "Bob" Kelso, M.D. , is a fictional character played by Ken Jenkins in the American comedy-drama Scrubs....
decides to offer full-body scans at Sacred Heart Hospital, despite the objections of Dr. CoxDr. CoxPercival "Perry" Ulysses Cox, M.D. , is a fictional character played by John C. McGinley on the American television comedy-drama Scrubs....
. This offer is taken by Harvey Corman, who is an "admittedly frugal hypochondriac".
See also
- Full body scanner
- Medical imagingMedical imagingMedical imaging is the technique and process used to create images of the human body for clinical purposes or medical science...
- Backscatter X-rayBackscatter X-rayBackscatter X-ray is an advanced X-ray imaging technology. Traditional X-ray machines detect hard and soft materials by the variation in transmission through the target. In contrast, backscatter X-ray detects the radiation that reflects from the target...
(for security scanning) - Millimeter wave scannerMillimeter wave scannerA millimeter wave scanner is a whole–body imaging device used for detecting objects concealed underneath a person’s clothing. Typical uses for this technology include detection of items for commercial loss prevention, smuggling and screening at government buildings and airport security...
(for security scanning)