RADIOLOGY is a medical specialty that uses ionising and non-ionising radiation for the investigation and treatment of diseases. There are two types of ionising radiation used in medical imaging, namely X-rays and gamma rays.

X-rays are used in the following procedures:

1. Plain X-rays include the common chest and abdominal X-rays and X-rays of practically any bone in the body.

Chest X-rays may form part of the routine medical examination in people seeking employment or going to school. They are also done in sick patients with pneumonia, heart disease or lung cancer to name a few illnesses.

Abdominal X-rays may be done in patients suspected of having kidney stones or in whom there is suspected bowel obstruction. The bones are commonly X-rayed when there is trauma or any of a number of bone diseases.

2. Fluoroscopy uses X-rays as well as a special radiographic “dye” to look at the gastrointestinal and urogenital tract, the female reproductive tract as well as the vascular system. Examples include patients with swallowing disorders, severe heartburn, suspected ulcers of the stomach or suspected cancers or inflammatory disorders of stomach, small or large bowel.

The tests go by the names of barium swallow, barium meal, small bowel follow through, or barium enema.

Hysterosalpingograms (HSGs) look at the fallopian tubes of women who are trying to get pregnant. Micturating cystourethrograms (MCUGs) look at the bladder and urethra of patients to investigate problems with urination. Angiograms allow us to look at the blood vessels of the body to diagnose areas of narrowing (stenosis) or dilation (aneurysm).

3. The computerised tomography (CT) scan has been popularised in music. In real life, it is not used to see money on the brain. It is used in many different ways to look at the organ system of the body. In the head, it is used when there is head injury or a suspected stroke or brain cancer to name a few of its purposes.

Practically any region of the body may be imaged by CT to look for anything ranging from trauma to any number of disease processes.

4. Mammography uses low-dose X-rays to screen for breast cancer. In Jamaica, routine breast cancer screening begins at 40 years of age for women. It may begin earlier if there is a first-degree family member who was diagnosed with breast cancer at an early age. Mammography is also used in men with breast masses.

Gamma rays are used in diagnostic nuclear medicine imaging and also in radiation therapy.

Medical imaging and radiation therapy are only two sources of ionising radiation to which the population is exposed. We absorb radiation from our environment. Everyone should be familiar with the use of sunblock to limit the UV radiation absorbed from the sun.

The dose of ionising radiation used in medical imaging is very low. It will not cause cancer. Nonetheless, repeated exposure adds up and one of the most important jobs of a radiologist is to use as low a dose of radiation as possible while achieving a satisfactory examination. Foetuses are especially sensitive to ionising radiation thus any woman who suspects that she may be pregnant should report this to the radiology staff before an examination.

Non-ionising radiation

Non-ionising radiation includes sound waves and electromagnetic radiation. They are used to perform ultrasound and magnetic resonance imaging (MRI), respectively.

An ultrasound may be used to image from the eyes to the toes and anything in-between. It is a quick, relatively inexpensive method for looking at soft tissues. It is less useful for imaging bones or air-filled bowels.

Ultrasound is commonly used in women with pelvic pain to diagnose fibroids or ovarian cysts for example. In the pregnant patient, it is used to evaluate the developing foetus. Identifying the sex of the baby before birth is now a requirement of the majority of expectant mothers.

MRI has many applications throughout the body. Its extremely high-contrast resolution allows it to look at the early stages of disease in the entire body. It is particularly useful for examining disease of the nervous system.

Interventional radiology

Interventional radiology is another arm of this fascinating specialty where disease processes are treated using the methods described above to guide surgical instruments. This allows patients to be treated through small incisions.

A common interventional procedure is a biopsy. A piece of diseased tissue is taken from the body using special needles so that the type of disease may be identified and appropriate treatment planned. Interventional procedures span the gamut from placing stents in narrowed blood vessels to blocking small arteries that supply fibroids so that they may shrink. New applications for interventional radiology are constantly being discovered.

Radiologist

A radiologist is therefore a medical doctor who specialises in the interpretation of medical imaging as well as the use of image guidance to achieve surgical intervention. The radiologist leads a team of imaging professionals usually composed of radiographers, ultrasonographers and other technical personnel.

The Jamaica Association of Radiologists represents radiologists in Jamaica. There are many radiology facilities in Jamaica which span the length and breadth of the island. Not every establishment that offers medical imaging is a recognised radiology facility so it is extremely important that patients become informed.

Get to know your radiologist.

Dr Duane Chambers is a consultant radiologist and founding partner of Imaging and Intervention Associates, which is located at shops 58 and 59 Kingston Mall, 8 Ocean Boulevard.