WOTD: Onychogryphosis

The effects of onychogryphosis. Photograph: Elord @wikidoc.org

"Onychogryphosis" - Abnormal thickening, hardening, and curving of the nails that occurs mainly in elderly people. Onychogryphosis may be associated with fungal infection or poor circulation.

"onychogryphosis". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p414.

X-Ray Generators

An interventional radiology theatre. Photograph: bsir.org

(Hey guys, sorry I haven't posted in a while!)

X-ray generators are devices that are used be radiographers to acquire images that are taken using x-rays to see the body's internal structures. They can also be used in sterilisation and fluorescence scans.

The main component of the x-ray generator is the x-ray tube. This tube contains a cathode which directs an electron-stream (don't cross the streams!) into a vacuum, and an anode which collects the electrons. The anode is made from tungsten, molybdenum, or copper, and when the electrons collide with it, only about 1% of the resultant energy is emitted as x-rays.

Many scientists have been involved with the development of x-rays, such as Hermann von Helmholtz, Johann Hittorf, William Crookes, Heinrich Hertz, Nikola Tesla, and of course Wilhelm Röntgen. 

X-ray imaging systems generally consist of an x-ray source, an image detection system, and a PACS. These imaging systems are used for many different applications, the most common and well-known one being for health-care/medicine. 

In medicine, the two main fields x-rays are used is radiography and fluoroscopy. Radiography is used to produce fast images of the internal bone structures and tumours, as well as treating them (radiotherapy). Fluoroscopy is used when real-time imaging is necessary. These types of x-rays are highly penetrating, ionising radiation and therefore are only used on dense tissues, like bones, as they absorb the radiation better than soft tissues. 

X-ray machines are also used in security measures. The most common of these is in airports or in schools. These x-rays are used to examine luggage for weapons, bombs. These x-ray systems are expensive but are non-invasive.

An advance in x-ray technology recently has been to the cathode which can be made from carbon nanotubes. These have been shown to provide 3-D images in less time than conventional x-ray machines do. Also, as they use less energy, they accumulate lower operational costs.

WOTD: Prolactinoma

Side-view MRI scan showing a Prolactinoma. Photograph: UCLA Neurosurgery

"Prolactinoma" - A noncancerous tumour of the pituitary gland the causes over-production of prolactin. In women, this may result in galactorrhoea, amenorrhoea, or infertility. In men, it may cause erectile dysfunction and gynaecomastia. In either sex, it may cause headaches, diabetes insipidus, and, if the tumour presses on the optic nerves, loss of the outer visual field. Diagnosis is made from blood tests and CT scanning or MRI of the brain. Treatment may involve removal of the tumour, radiotherapy or giving the drug bromocriptine.

"prolactinoma". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p466.

WOTD: Embolism

A CT scan showing a pulmonary embolism. Photograph: mediexchange.com

"Embolism" - Blockage of an atery by an embolus. Blood clots that have broken off from a larger clot located elsewhere in the circulation are the most common type of embolus. Pulmonary embolism is usually the result of a fragment breaking off from a deep vein thrombosis and being carried via the heart to block an artery supplying the lungs; this is a common cause of sudden death. Blood clots may form on the heart lining after a myocardial infarction, or in the atria in atrial fibrillation, and then travel to the brain, resulting in a cerebral embolism, which is an important cause of stroke.

Symptoms of an embolism depend on the site of the embolus. Pulmonary embolism can lead to breathlessness and chest pains. If the embolus lodges in the brain, a stroke may occur, affecting speech, vision, or movement. If an embolism blocks an artery to the leg, the limb will become painful and turn white and blue. Untreated, gangrene may develop. In serious cases of fat embolism, heart and breathing rates rise dramatically, and there is restlessness, confusion, and drowsiness.

Embolectomy (surgery to remove the blockage) may be possible. If surgery is not possible, thrombolytic and anticoagulant drugs may be given.

"embolism". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p196.

Radiography Assistants & Imaging Support Workers

A CT scanner team consists of two radiographers, a radiologist and a radiography assistant.

Photograph: NHS

Okay, so I was looking into my options if the unexpected happened e.g. if I  :

a) didn't pass my Access course this year

or

b) didn't manage to get a place onto a university course. And I was looking around, and I discovered support roles in radiography! (Even if I don't get a place for 2013, I will still apply again for 2014!)

Radiography assistants and imaging support workers are people who assist qualified diagnostic/therapeutic radiographers. These assistants have certain responsibilities depending on the nature of their team's work.

They generally aid patients as part of their job role, but their other duties include:

• processing film images
• preparation and assistance in general/specialised procedures 
• keeping the working environment hygienic and clean
• preparing treatments
• manual handling of patients
• basic equipment maintenance
• recognising and reporting faulty equipment

To work as a radiography assistant/imaging support worker, there are no formal entry requirements, but 4 or more GCSEs, or their equivalent may be required for more advanced work. There is an NVQ available, but it is not a route towards qualifying as a radiographer. It is also possible to get into this role via a level 3 apprenticeship.

These workers are usually train while on the job, but there are short courses available. The Society of Radiographers (SoR) has developed accreditations for assistant practitioners working in these settings. It is to ensure the qualifications and training is recognised by the NHS. It is also possible to work while studying part-time towards a professional radiography degree.

So, again, there's always a way to learn about the job even if the scary things happens!

WOTD: Venepuncture

A contrast-enhanced venography in a 78 year-old man with thrombosis of the deep veins in the lower leg.

Photograph: ajronline.org

"Venography" - A diagnostic procedure that enables veins to be seen on an X-ray film after they have been injected with a substance opaque to X-rays. It is used to detect abnormalities or diseases of the veins, such as narrowing or blockage from thrombosis.

"venography". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p581.

WOTD: Barotrauma

Chest x-ray of Barotrauma in a patient with status asthmaticus. Photograph: realicu.com

"Barotrauma" - Damage or pain, mainly affecting the middle ear and facial sinuses, that is caused by changes in surrounding air pressure. Air travellers are at the greatest risk, but scuba divers face similar problems.

Aircraft cabin pressure decreases as the plane ascends and increases as it descends. As the aircraft ascends, the ears may "pop" as the air in the middle ear expands and is expelled via the eustachian tubes, which connect the middle ear to the back of the throat. On descent, the higher pressure may push the eardrum inwards and cause pain. Minor pressure damage in the middle ear may cause pain, hearing loss, and tinnitus for a few days; damage within the facial sinuses may also cause pain, and possibly a discharge of mucus or blood. Symptoms usually wear off within hours or days, but treatment may be needed if they worsen or persist. Large pressure changes can rupture the eardrum.

Barotrauma can be avoided by vigorous swallowing or by forcibly breathing out with the mouth closed, and the nose pinched (the Valsalva manoeuvre). This action equalises the internal and external pressures in the middle ear and sinuses. If the eustachian tubes are blocked, as commonly occurs with a cold, use of a nasal spray containing a decongestant drug is recommended shortly before the descent of the aircraft. 

"barotrauma". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p66.

CT and Sir Godfrey Hounsfield

Sir Godfrey Newbold Hounsfield. Photograph: mc.vanderbilt.edu

Sir Godfrey Newbold Hounsfield CBE, FRS (28 August 1919 - 12 August 2004) was an English electrical engineer who shared the Nobel Prize for Physiology or Medicine with Allan McLeod Cormack, for his part in developing the diagnostic technique of X-ray computed tomography. 

The Hounsfield scale, a measure of radiodensity used in CT scan evaluations, is named after him. The scale's units is defined in Hounsfield Units.

Godfrey was born in Sutton-on-Trent, England. He had two elder brothers and two elder sisters. He was intrigued by electrical gadgets, and he tinkered with his own electronic machines, launched himself off haystacks with his own home-made glider, and almost killed himself by using water-filled tar barrels. He went to Magnus Grammar School and excelled in physics and mathematics.

Just before World War II, he joined the Royal Air Force, where he learned the basics of electronics and radar. After, he attended Faraday House Electrical Engineering School. He graduated with a Diploma of Faraday House.

In 1951, he began working at EMI Ltd, where he began researching guided weapon systems and radar. It is here he became interested in computers and helped design the first commercially available all-transistor computer: the EMIDEC 1100. 

Hounsfield came up with the idea that one could determine what was inside a box by taking X-ray readings at all angles around the object. He then constructed a computer that could take X-rays input at varying angles to create an image of the object in "slices". Applying this to the medical field led him to propose what is now known as computed tomography. At the time, Hounsfield was not aware of Cormack, who had done work on the theoretical mathematics for such a device.

Hounsfield built a prototype head scanner and first tested it on a preserved human brain, then on a fresh cow brain from a butcher shop, and later on himself. On 1 October 1971, CT scanning was introduced into medical practice with a successful scan on a cerebral cyst patient at Atkinson Morley Hospital, London. In 1975, Hounsfield built a whole-body scanner.

WOTD: Talipes

Left congenital talipes as seen by three-dimensional ultrasound at 22 weeks gestation. 
Photograph: International Federation of Gynecology and Obstetrics

"Talipes" - A birth defect (commonly called club-foot) in which the foot is twisted out of shape or position. The cause may be pressure on the feet from the mother's uterus, or a genetic factor. The most common form is an equinovarus deformity, in which the heel turns inwards and the rest of the foot bends down and inwards. It is treated by repeated manipulation of the foot and ankle, starting soon after birth. A plaster cast, or strapping may be used to hold the foot in position. If this is not successful, surgery will be needed.

"talipes". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p538.

WOTD: Retinoblastoma

A young child with retinoblastoma in the left eye. Photograph: Gordon K. Klintworth

"Retinoblastoma" - A cancer of the retina that affects infants. The first indications of this disorder may be a squint caused by blindness in the affected eye or a visible whiteness in the pupil. Without early treatment, retinoblastoma can spread to the orbit (eye socket) and along the optic nerve to the brain.

Retinoblastoma has a genetic basis. People with this cancer lack part of one of the chromosomes in pair number 13. Newborn infants from affected families should have genetic counselling.

Treatment is by removing the eye, or by radiotherapy. If both eyes are involved, the one worse affected by removed and the other given radiotherapy.

"retinoblastoma". British Medical Association (2007). Illustrated Medical Dictionary. 2nd ed. London: Dorling Kindersley (DK). p489.