STI: How safe is an X-ray?

April 9, 2009

How safe is an X-ray?

It is safe to do several X-rays in a year, say radiologists. POON CHIAN HUI reports

 

Most people do not think much about going for an X-ray. However, some have their reservations.

 

There are those who believe that X-ray exposure can cause serious side effects like giddiness. Others even believe it can cause infertility, said Mr Gabriel Leong, a radiography manager at Changi General Hospital (CGH).

 

The hospital receives occasional inquiries from members of the public regarding the safety of X-rays.

 

'Patients have asked if radiographers can have children,' MrLeong said with a laugh.

 

What tops the list, he said, was the question: 'Can X-rays make me glow in the dark?'

 

Such fears are unfounded, he said.

 

The bad reputation of X-rays may stem from the fact that they are a form of radiation. The word 'radiation' conjures negative images in people's minds, said DrChong Le Roy, a consultant radiologist at CGH.

 

'People have the impression that any form of radiation exposure is detrimental, given the devastating consequences of well-known events such as the atomic bomb attacks on Japan,' he said.

 

An X-ray is a specific type of electromagnetic radiation which also includes visible light, ultraviolet rays and microwaves.

 

The difference is that X-rays have a higher frequency, meaning that the beams contain more energy, said Dr Chong. Hence, they are able to penetrate the human body. While a regular X-ray gives a two-dimensional image, CT scans produce three-dimensional images.

 

While high levels of radiation are indeed harmful, an X-ray carries minimal risk, said Dr Chong.

 

This is because the dosage is very small. One is exposed to radiation for only a few milliseconds, he said.

 

'In fact, a four-hour flight gives you about the same amount of radiation as a chest X-ray,' said Dr Chong.

 

This is because flying takes one nearer to the sun which emits cosmic radiation. Radiation can penetrate most solid materials.

 

We are also constantly exposed to background radiation, said Dr Chong. Radiation in the atmosphere comes mostly from the soil and the sun but tiny amounts are also present in food and water, he said.

 

'It's important to put things in perspective,' said Dr Chong. 'We receive radiation all the time but it does not cause any major harm - neither do X-rays.'

 

Hence, it is safe to have several X-rays in a year for medical reasons, he said. However, as a precaution, pregnant women or those who might be pregnant are advised to discuss the need with their doctors.

 

Besides, the speed of detection and early treatment made possible by the use of X-rays far outweigh the negligible amount of radiation exposure, said Mr Leong.

 

'With a CT scan, we can diagnose a problem immediately,' he said.

 

'What people should remember is that medical radiation is highly controlled and it is meant to help you get proper treatment as early as possible,' he said.

 

chpoon@sph.com.sg

 

A 4-hour flight gives you about the same amount of radiation as a chest X-ray