Children are especially prone to the cumulative effects of x-rays and other x-ray based imaging technologies; Schneider Children’s recently introduced use of the newest digital device that reduces up to 90% of the radiation absorbed by the body; the hope is that this new technology will soon reach other hospitals in the country

The discovery of x-rays in 1895 was one of the greatest revolutions in the world of medicine. Imaging machines that are available today for medical purposes succeed in diagnosing diseases even years before their clinical appearance and direct the performance of complex surgical procedures leading to complete recovery from illnesses. An x-ray radiograph reveals the difference in the density of organs in the body, mainly bones, while soft tissues appear like dark and faint shadows that can be observed under fluoroscopy (screening) of the digestive, respiratory and urinary tracts following the introduction of opaque media (such as barium).

However some x-ray imaging exposes the person to a high amount of radiation that can harm human tissues and cause minute changes to the DNA, thus raising the risk of late neoplasia. Recently, Schneider Children’s Medical Center introduced new digital imaging devices which can reduce up to 90% of the radiation dosage absorbed by the child’s body.

Today, it is customary to take x-rays of the chest, abdomen, colon, urinary tract, skeletal bones and so on. During the procedure, an x-ray cassette is placed immediately under the area to be examined and the patient is requested not to move during the exposure which takes milliseconds. Fluoroscopy (screening) can also be performed whereby a series of continuous x-rays, pretty much like an animated movie, reveal physiological processes inside the body. One fluoroscopic study can sometimes require several minutes of continuous x-ray imaging.

Because of the risks of radiation, a special device provides protection during the x-ray procedure and is placed over the thyroid and genital areas, which are particularly prone to cancer following exposure to extensive x-ray radiation. Owing to the risks of congenital birth defects, x-rays are not usually permitted in pregnant women. “Knowledge regarding the risks of radiation was gathered from the survivors of Hiroshima and Nagasaki,” explains Prof. Gadi Horev, Director of the Institute of Pediatric Imaging at Schneider Children’s Medical Center. “Some of these people were exposed to amounts of radiation similar to that emitted by a CT scanner, and as a result of their later cancers, awareness was raised of the need to reduce exposure to ionizing radiation in medical imaging studies as much as possible.”

In a special directive issued at the beginning of this year by Prof. Avi Yisraeli, Director General of Israel’s Ministry of Health, it was stipulated that radiation dosage emitted by x-ray machines, CT in particular and especially when dealing with children, raises the risk of cancer. A joint committee of the Ministry of Health and various medical specialists determined that exposure to x-ray radiation must be reduced as far as possible through digital recording media, shorter exposure times, meticulous use of protective devices, and new machinery that emits less radiation.

The solution for the future is believed to be even simpler: for instance, the MRI will produce the finest image quality without radiation through the use of magnetic fields and radio-wave transmission, which will become the main mode of medical imaging. But this will not happen soon, especially not in Israel. “In this respect, we are still in the third world,” says Prof. Horev. “The number of MRI machines in Israel is among the lowest in the world: 1.3 machines per 1 million citizens.”

In the wake of Schneider Children’s, a number of other hospitals acquired similar radiographic imaging devices, although only Schneider Children’s made the complete changeover to digital technology 10 years ago. The new system is called Double Density CR technology that doubles the sensitivity detection of x-ray radiation and enables reduced exposures to 25% or less, as compared to standard x-ray film exposures. The processor scans the x-ray image detector through special laser illumination. The x-ray image finally appears as a computerized digital picture that can be viewed and stored electronically.

At the same time, Schneider Children’s introduced a new diagnostic imager where the examination area is ‘illuminated’ during real-time fluoroscopy through very short pulses of x-ray radiation, 10 times per second for about 20 thousandths of a second each time, as opposed to continuous radiation with the existing fluoroscopy machine in use. In this way, radiation to the child is reduced by up to 90% during fluoroscopy.

“The new detectors, the sophisticated scanner and the digital x-ray processing contribute to a reduction of radiation by tens of percent,” says Prof. Horev. “The importance is tremendous, more so with premature infants who need to have x-rays almost daily. In children, there is a danger of absorbing greater amounts of radiation as their sensitivity is ten times higher than adults. In addition, children have many more years than adults to express the DNA damage as cancer.”

The new network is in the process of being introduced as well at Rambam, Sheba, Hadassah and Ichilov Hospitals. And the hope is that it will arrive at other hospitals in the country in the future.