Dr Amit Chakraborty, Jan 2023
A Comprehensive Guide to X-rays and How They Work
X-ray is a type of electromagnetic radiation which has a wavelength much shorter than that of light. Electromagnetic waves that have shorter wavelengths than light have more penetrating power. Light waves cannot penetrate the skin and therefore is unable to show the interior of the human body. However, due to higher penetration power, x-ray is able to traverse through skin and flesh and some parts of the bones. As a result, x-rays are often able to visualise bony structures.
What conditions can be diagnosed with x-ray?
X-ray is reflected by bony surfaces within the human body. As a result, most bony conditions are visible on x-ray. Sometimes the x-ray is able to conclusively diagnose a bony condition. Other times further testing such as a CT scan or MRI may be necessary to clarify the findings initially detected by an x-ray examination.
Air containing structures (such as lungs, sinuses) are also quite well interrogated by x-ray beams. These structures are often lined by other visible soft tissue or bony structures such as the surrounding bones or blood vessels. These give the air containing structures a clear outline when visualised on an x-ray film.
Some subtle soft tissue abnormalities can also be detected by x-ray. These usually require high quality radiograph (an x-ray) and an experienced specialist to look at it (such as a radiologist).
Common conditions that can be diagnosed with x-ray:
Fractures: a quick, readily accessible, and relatively inexpensive way of diagnosing fractures is x-ray. X-ray often shows the presence or absence of a fracture, its orientation, degree of movement or displacement and involvement of a joint. Most fractures do not require any further investigation although sometimes if the fracture is near a joint or fragmented into several pieces, further characterisation may be necessary with a CT scan.
Other bony conditions: unexplained musculoskeletal pain is often investigated with an x-ray examination as the first line. This can detect conditions such as osteoarthritis, rheumatoid arthritis or other forms of arthritis, gout, abnormal bony growth, infection in the bone or even bone tumours.
Soft tissues: often x-rays may show subtle cues of injury by the disturbance in the soft tissue planes. If there is a haematoma (blood collection), the soft tissue planes can be distorted. Sometimes abnormal calcification in the soft tissues may point to certain conditions.
Imaging of the chest: lungs and all the associated structures are quite clearly visible on a good quality x-ray. Various lung conditions can be diagnosed with an x-ray, such as infection, fluid collection (pleural effusion), pneumothorax (air leakage from the lungs), injury to the lung tissue, injury to the chest wall such as rib fractures, conditions of the diaphragm, the size of the heart and the large vessels in the centre of the chest.
Imaging of the abdomen: certain conditions such as moderate to severe constipation, bowel obstruction, certain gallstones or kidney stones are visible in an abdominal x-ray. This is a useful test for children with abdominal pain.
Imaging of the spine: x-rays are commonly used as the initial test for the spine. A lot of information can be obtained from these cheap and readily available examination. The curvature of the spine, the heights of the vertebral bodies, their bony densities, the spacing between the vertebral bodies (disc spaces), the state of the spinal canal, the appearance of the soft tissues surrounding the spine etc can be very easily detected by an x-ray.
Dental imaging: specialised x-rays known as OPG are commonly used by dentists to look at the condition of teeth and the bony sockets. Various diseases are visible in a correctly performed OPG.
Soft tissue calcification: when abnormal calcification occurs within certain soft tissues, x-rays can be a useful tool to detect them. Examples include gallstones, kidney stones and other conditions producing calcification within various soft tissue structures such as tendons and ligaments.
Specialised x-rays: various other forms of specialised x-rays are used for certain purposes by specific specialists. Appropriate development of bone in young children can be assessed by x-rays. Using specialised x-rays Orthopaedic surgeons assess discrepancy between limb lengths in order to plan corrective procedures. Other conditions such as pelvic tilt, abnormal spinal curvature such as scoliosis and so on can be correctly diagnosed with an x-ray.
What are the advantages of x-ray?
Readily available: Almost all imaging centres have an x-ray machine. Obtaining an x-ray takes seconds. Most places usually cater for walk in patients. Therefore, it is readily available and almost ubiquitous.
Cheap: most places Bulk Bill x-rays. Some specialised x-rays may attract a small out-of-pocket fee, but this is usually very small.
Radiation dose: x-rays are a form of radiation. However, the amount of radiation dose received from an x-ray is very small. The international authorities have come to a consensus about the safe amount of radiation dose that can be received by an individual in a given year. This amount is 20 mSv. A chest x-ray, for example, produces a radiation dose of 0.1 mSv.
Time and preparation: most x-rays do not require any preparation. These are usually extremely quick examinations that take only a few minutes to perform. Therefore, x-rays are very useful tools to quickly detect a potential fracture or any other acute condition.
What are the disadvantages?
X-ray cannot accurately detect soft tissue abnormalities. Major soft tissue organs such as the brain, internal abdominal organs, the interior of the heart etc are not able to be examined by x-ray.
X-ray beam can be severely attenuated by patient’s body habitus. As a result, x-rays taken on large patients tend to be of poor quality. The diagnostic value is limited.
Certain x-rays require patients to place their body in a certain position. This is sometimes challenging due to pre-existing conditions, pain, immobility, or other factors.
The information obtained by x-ray is very basic. Sometimes more information is required for accurate diagnosis. Other tests such as ultrasound, CT scans or MRI may be useful in these cases.
X-ray and pregnancy: radiation is harmful for unborn babies. As a result, x-rays are not recommended for patients that are pregnant or could be pregnant.
Two-dimensional imaging: x-rays offered two-dimensional imaging. This is like taking a picture. Other imaging modalities such as CT scans can produce three-dimensional images which can show a lot more detail.
A note about quality:
Not all imaging centres, and therefore not all x-rays are the same. A great deal of skill, knowledge and understanding is required to obtain high-quality x-rays and to interpret them accurately. A poorly obtained x-ray can easily miss a diagnosis. Therefore, it is essential to choose a medical imaging clinic with a good reputation when getting x-rays.
At CareScan, we maintain a very high quality of all our medical imaging services. Our technicians and doctors undergo regular professional development programmes. Our latest equipment, highly skilled and experienced professionals and superior care ensures that our patients have a great experience whilst visiting our clinics. It also means that our x-rays are high quality images. Fast, accurate and reliable reports from our radiologists mean that your doctor can receive the results and manage your condition quickly and efficiently.
Summary
X-rays is the most basic form of medical imaging. Despite all the latest advancements in other forms of imaging, x-ray remains as the basic cornerstone of imaging for a range of conditions. Its ease of access, reliability, low radiation dose makes it a valuable diagnostic tool even in the modern era of medical imaging.