Myths of Radiology

Radiology comprises three specialities in medicine, namely Diagnostic Radiology (mainly imaging), Radiation Oncology (treatment of cancers) and nuclear medicine (radio-isotopes for diagnostic and therapeutic purposes). The largest of the three specialities is Diagnostic Radiology (DR) which uses x-rays, ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) to image the body and diagnose diseases. Much of modern medicine depends on diagnoses based on imaging to institute treatment by drugs or surgery. In the last 3 decades, DR has also developed an interventional arm that uses imaging to guide therapeutic procedures.

Because radiological imagings are very frequently used to verify the presence of cancer, people have many misconceptions on the nature of radiology. This short article attempts to debunk such myths and present the facts.

DIAGNOSTIC RADIOLOGY

Myth 1:Radiology is a cold and boring profession-all radiologists do all day is read films.

Truth: While reading films is a part of the job, radiologists do other things besides. Radiologists who do ultrasound tests for pregnant women or perform interventional procedures have a lot of interaction with patients. Far from being boring and cold, radiology offers a great opportunity to spend time with people in need.

Myth 2:Women should not be radiologists because the radiation will affect their reproductive capabilities.

Truth: Radiation can affect a woman's reproductive capabilities, but this is only in cases where a woman's pelvic area receives direct radiation, e.g. when a female colon cancer sufferer undergoes intense radiotherapy in this area. In such cases, the ovaries would be killed.

Modern radiation equipment and radiation protection practice shields radiologists and allied professionals from significant radiation doses. For patients, the lowest possible radiation dose is used.

Radiology scans involving other parts of the body such as the head are also unlikely to affect a woman's reproductive capabilities. This also goes for X-ray examinations of the whole body.

Myth 3:Pregnant women cannot undergo any sort of radiology scan in case the radiation harms the unborn child.

Truth: Yes and no. Ultrasound scans, which use non-ionising radiation, are used to monitor the development of growing foetuses in pregnant women. They certainly do not harm the unborn child.

Other kinds of scans, though, may be harmful to pregnant women. Generally, if a woman is pregnant, doctors will try to avoid giving her any radiology scans unless absolutely necessary. In such cases, doctors will provide protective garments to the pelvic area to protect the unborn child. Doctors will weigh the benefits of a scan to the woman versus the risks to the foetus. If the benefits outweigh the risks, the scan goes ahead.

Myth 4:We only get radiation from nuclear bombs and radiology tests.

Truth: We get radiation from the natural environment around us as well. A simple comparison between background radiation and radiation from radiological procedures will show us how much radiation we are actually exposed to naturally.

Radiation doses are measured in millisievert (mSv). The amount of radiation a woman gets from a mammography, for example, is 0.7mSv, the equivalent of a mere three months' natural background radiation exposure. A CT scan of the head, a life-saving procedure to detect brain tumours, is worth 2mSv of exposure, which is equivalent to eight months of natural background radiation.

Myth 5:Radiation is dangerous, therefore radiology scans are dangerous.

Truth: Radiation is dangerous only in large amounts. Radiology scans are relatively safe as most scans do not use a high level of radiation. For those that use higher levels of radiation, the benefits to the patient (detecting tumours, killing tumours) outweigh the risks of the higher radiation level.

Myth 6:Since the amount of radiation from most tests is low, I don't need to keep track of how many scans or what type of scans I've had.

Truth: You should keep a record of such medical tests, especially if you have had, say, frequent X-ray exams or changed doctors a couple of times. This is because while scans involving lower doses of radiation are rather safe, other scans such as computed tomography (CT) scans that involve contrast materials (dyes) like barium or iodine use higher doses of radiation. If you have had several higher dosage radiation scans, exposing you to more radiation via more tests might not be wise.

In such cases, the radiologist would need your medical history to determine if the benefits of extra scans outweigh your previous radiation exposure. Pregnant women or women who suspect they are pregnant should inform their doctor so their doctor can take the necessary precautions.

Myth 7: All doctors know how to interpret radiological images.

Truth: All doctors have a little training in radiology during their undergraduate medical course. In the years after graduation, they also gain some experience in looking at images as they care for patients. However radiologists need at least 5 more years of specialist training and experience in order to correctly interpret the wide variety of images. They have to learn both normal variants and disease patterns to correctly analyse and interpret the scans. Thus it is best for patients that all radiological images are interpreted by those specially trained to do so.

Myth 8:Outsourcing radiology will benefit local patients.

Truth: Because images are now digitally acquired, it is possible to send them thousands of miles away for remote interpretation. In big countries with remote rural areas, trained radiologists may not be locally available. Outsourcing, then, provides remote communities with radiological expertise from distant cities. This has little relevance in a city state like Singapore. On the other hand, outsourcing to India for example, can potentially reduce cost since labour is cheaper there.

It is important to ensure that reporting of outsourced radiological images are made by well trained and qualified radiologists. Regular audits should be done. A high standard of English language is also important to avoid misunderstanding. As laws vary from country to country, an aggrieved patient may find it difficult to sue an outsourced radiology provider.

RADIATION ONCOLOGY

Myth 9:After radiation therapy, I will remain radioactive and I can't share food with my family.

Truth : Many cancers nowadays are treated using linear accelerators which only emit radiation during the treatment process. There is no residual radioactivity remaining in the patients after treatment. Certain treatments like brachytherapy for prostate or radioisotope treatment for thyroid cancers will use live radioactive sources, but the patient's radioactive levels are monitored in hospital and discharged only when deemed safe for public. There is usually no problem with casual contact like sharing food among family members.

Myth 10:I will get another cancer due to radiation after radiotherapy treatment.

Truth: The risk of second cancer after radiation is often overestimated. Long term, large follow up studies of cancer survivors show that the rate of second cancers remain consistently low and is related to several factors like early age of irradiation and dose received. Often the benefits of radiotherapy for cancer treatment far outweigh the small risks of developing second cancers in the distant future. Your doctor can make a judgement and advise you of your risks.

NUCLEAR MEDICINE

Myth 11:Nuclear medicine scans are very fast, like X-ray procedures.

Truth: X-ray imaging is usually very fast because the machine emits a very short burst of radiation to produce the picture. Nuclear medicine scanners, on the other hand, do not produce radiation. The radioactive material is placed inside the patient's body. For patient safety this radiation dose is kept as small as possible, and so it takes a relatively long time to take pictures.

Myth 12:If the radiation is placed inside the body it must be very harmful.

Truth: In Nuclear Medicine, the radioactive materials may be placed into the body in order to obtain diagnostic information (e.g. bone scans), or larger doses could be employed for treating certain diseases (e.g. thyroid cancer). For diagnostic scans, the amount of radioactive material needed to produce the image is usually very small, and the radiation doses for most scans are similar to X-ray procedures. For radioactive treatment procedures, the radiation doses and side effects will depend on the type of treatment. Specific advice will be given for each case.

Myth 13:Nuclear medicine studies can be done on short notice.

Truth: Nuclear medicine studies utilise radioactive materials in various chemical forms (radiotracers) to generate images. As the materials undergo radioactive decay, these have to be imported or produced locally just before the scan. Nuclear medicine scans can only be done only if there is radiotracer available. The more common routine scans can usually be done on short notice, whereas some specialised scans may require several days for the specific radiotracer to be imported.

Myth 14:If I am late for my study it can still be done when I get there.

Truth: Nuclear medicine studies use radioactive materials, which undergo constant decay, whether it is inside or outside the patient. After a limited time there will no longer be sufficient radioactivity to produce an image. Also, most scans are performed specifically to observe the way in which the body handles the radiotracer, and hence the timing is critical to obtaining useful information. This is why it is important to observe the instructions and timings given by the nuclear medicine staff.

Myth 15:A PET scan is for pets.

Truth: PET is an acronym for Positron Emission Tomography. This describes the phtotons emitted from positron annihilation events, which are imaged tomographically to generate 3D data sets. The term does not describe who or what is getting a scan. Whilst research studies may involve animals, PET scanners in hospitals are used for scanning humans only.