X-rays and imaging studies to diagnose cancer have an important role to play in completing investigations in detecting the presence of cancer.
The role of radiology involves plain x rays and specialized imaging studies that help detect cancer in early stages and also identify its stage. They help to know the size and location of the primary tumor and identify metastasis if present.
The chance of cure for a cancer patient strongly depends on how early the cancer is diagnosed. When cancer is diagnosed early, before it grows and spreads, the treatment is more likely to be successful.
Imaging techniques have advanced and the results they produce have become an important part of early cancer detection in different parts of the body including bones and the body organs such as the stomach and kidneys.
The results of radiological studies are available quickly and the procedures are painless and quick. They are, therefore, of pivotal importance in early cancer diagnosis and successful management.
Contrast studies, however, require more preparation before the procedure and can be somewhat uncomfortable with some side effects.
Why diagnostic radiology is important? How does it help?
X-rays and imaging studies to diagnose cancer offer value far beyond just diagnosing the malignancy. Diagnostic radiology and nuclear medicine studies help doctors in dealing with cancer in the following ways:
- To screen for cancer
- Find the location and size of the tumor
- Help in knowing the stage of cancer
- To know if the cancer cells have invaded the neighboring tissues
- To identify if there is any metastasis to other organs or tissues of the body
- Plan therapy
- Evaluate therapy response
X-rays and Imaging tests for cancer
Radiology studies to detect cancer involve using plain x rays and advanced imaging tools such as CT scans, MRIs, and ultrasound to find details of the cancer lesion. These studies include:
- A plain x-ray may give evidence in certain cancers. For example, the doctor can visualize a cancer growth in the lungs or a bony growth on a plain x-ray.
- CT scan (Computed Tomography Scan) is an imaging procedure, which provides horizontal and vertical cross-section images of the chest, abdomen, and pelvis. It helps the doctor in knowing the exact location and size of the growth and presence of any invasion into the neighboring tissues. It is useful in diagnosing the presence of growth in the lungs, pancreas, and liver.
- MRI (Magnetic Resonance Imaging) is a radiological investigation that provides detailed images of structures in the body using magnetic waves. It proves to be especially useful for the study of the brain, heart, liver, reproductive organs, pancreas, and soft tissues. It provides a more detailed picture of the cancer tumor in the above tissues than a CT scan in certain cases.
- PET scan or Positron Emission Tomography is a procedure of nuclear science, which has given a new level of study to diagnose cancer. PET studies help to study the metabolism, physiology, anatomy, and properties of the organ and the tissues. Its detailed digital pictures help to identify activity at the cellular level. Its advantage over CT scan and MRI, therefore, lies in the fact that it can help diagnose cancer even before any anatomical changes take place. It also helps to differentiate between benign and malignant changes.
- Mammography is a specialized X-ray procedure where the breasts are x rayed for confirmation or sign of any tumor. Mammography can detect a breast tumor much before it can be felt by hand. It is recommended in patients with breast cancer and also in patients exposed to high cancer risk factors, and those with a family history of cancer.
Endoscopic ultrasound is a procedure used to view and detect a growth inside the gastrointestinal tract and the pancreas. This endoscope is more specialized than a normal endoscope as it can help view the surrounding tissues as well. An endoscopic ultrasound also has the facility to take a biopsy of a suspected tissue for histopathology studies, to confirm cancer.
Risks of radiological studies
Radiological studies are not without risks. There’s been a lot of talk in the media and patients about radiation exposure from medical imaging, and whether the exposure will increase their risk of developing cancer. Here are facts and the clarification on doubts expressed.
X-rays expose you to radiation. Many people believe that this exposure can lead to cell mutation, which can lead to cancer. This is partially true. The amount of risk due to radiation depends on the tissue or organ being x-rayed. Similarly, sensitivity to radiation depends on the age of the individual with children being more susceptible than adults are.
However, radiation exposure from one single X-ray is low and the benefits of the results and interpretation from these tests far outweigh the risks.
For most women, the risk from routine mammography or dental x-ray is small. However, if you are pregnant your doctor may order an ultrasound although the risk of X-rays to an unborn baby is small.
The American College of Radiology recommends that during your lifetime, you should not exceed diagnostic radiation exposure beyond 100 mSv, which is the equivalent to about 10,000 chest X-rays and 25 chest CT scans.
CT scanning and nuclear imaging have greatly improved the ease of cancer diagnosis. It has almost done away with the exploratory surgeries and risky procedures that were once necessary. The benefits of these tests far outweigh the risk of radiation. The risk from a single CT scan or nuclear imaging test is minimal.
Side effects of contrast medium
Contrast medium is a radio-opaque chemical substance that is introduced into a part of the body for better visibility of internal structures during radiography such as the blood vessels and the gastrointestinal tract.
These contrast media are injected into veins or arteries, or within the disks or the fluid spaces of the spine, and into other body cavities depending on the area of the body to be viewed.
They can be used for X-rays, CT scans, MRIs, and ultrasound.
In some people, the injection of a contrast medium can cause side effects. They can include:
- A metallic taste in the mouth
Severe reactions to a contrast medium though rare can include:
- Severe low blood pressure
- Anaphylactic shock
- Cardiac arrest