What Is Medical Imaging – X-Ray, Ultrasound, CT, MRI & PET Scan?

I am concerned about my health. Can I request for a medical imaging scan at a healthcare facility?

According to the MOH, for national health screening initiatives, a referral from a medical practitioner is not required. This is because healthcare facilities that wish to provide health screening for national programmes are first required by Health Promotion Board to have systems in place to ensure that patients receive timely follow-ups on the screening results from the appropriate medical practitioner(s). For any other health screening, a referral from a medical practitioner is required.

You should confirm with the healthcare provider if a referral is required for your desired scan.

Why is medical imaging important for health screening or early detection of diseases?

Many serious conditions are “silent” and do not present any symptoms in the early stages. Such diseases may require a variety of tests to be detected and diagnosed. Medical imaging is a vital component of the set of medical examinations needed.

Some health screening packages allow me a choice of 1 or 2 medical scans. Which one should I choose?

Different medical imaging scans help to detect different medical conditions. Generally, you can consider selecting those for conditions that you are most at risk for (e.g. family history of the condition or other risk factors).

You should consult the doctor to ascertain the choice that is most suitable for you.

Is radiation exposure from medical imaging scans harmful?

Certain examinations such as X-ray, CT scan, mammography, bone mineral densitometry, and PET scan will expose the patient to low doses of radiation. With current technology, radiation risk from medical imaging is sufficiently low to not cause harm.

Female patients who are pregnant, or for whom if pregnancy is a possibility, should inform the attending doctor, radiographer or nurse.

I am worried about the discomfort or radiation exposure from a mammogram. Can I take a breast ultrasound instead for breast cancer detection?

A mammogram uses x-rays and is currently the best screening tool for breast cancer detection. There are nonetheless limitations including the possibility of false negatives (i.e. cancer not detected), and false-positives (i.e. cancer is indicated when it is not present actually). 

A breast ultrasound examination is usually used as an adjunct to mammography,  rather than used as a replacement. A breast ultrasound is commonly used to further investigate an abnormality detected by a mammogram. Breast ultrasound is not typically used for breast cancer screening as it may miss some early signs of cancer. Some studies have shown that ultrasound may improve cancer detection in younger women or in women with dense breasts (which is common for Asian women).