Looking back to see the future

Channel back a half-century to the watershed events that led to the modern age of imaging and you'll find good ideas struggling to take root. PET is an example. Despite its relatively recent adoption, PET was first used in the 1970s, a fact that is easy to forget.

Other technologies have become obscured, ironically, by the very advances that have made them relevant. An example is coronary CT angiography. The evolution of detectors to allow 64-slice acquisitions made this possible, but the underlying shift from axial to spiral scanning threatens to overshadow an improvement needed to minimize patient dose.

This technology, step-and-shoot, is already on the U.S. market as part of GE Healthcare's portfolio. Later this year, Philips is expected to sell it as well. Step-and-shoot dramatically cuts the dose of x-rays administered during coronary CTA. If CT screening for heart disease is to reach its potential, patient dose is a serious issue that has to be addressed.

This solution for the future came from the past, when the detector or x-ray source made a single pass around the patient, who then "stepped" forward to allow the next slice.

By minimizing overlap between ECG-gated slices of the heart, step-and-shoot CT can cut patient dose by 70%. But it also provides a model for finding solutions among approaches that were once dismissed.

In the August issue of Physics Today, an international team led by researchers at the Technion-Israel Institute of Technology in Haifa reports that low-intensity electric fields, applied daily for hours at a time, can disrupt the division of cancer cells and slow the growth of brain tumors. Such low-intensity alternating electric fields were once believed to do nothing more than heat cells.

The promising results, based on a small human trial but bolstered by animal and laboratory experiments, give hope that the progression of glioblastoma multiforme, a form of brain cancer with an extremely low survival rate, could be slowed or even forced into regression.

The potential of this electrotherapy points out that in the rush to embrace modern developments, solid solutions may be overlooked. A technology such as step-and-shoot may incorrectly be considered old.

While step-and-shoot CT may not be suited to all patients - an irregular or rapid heart beat is a contraindication - it will be a welcome option if and when coronary CTA takes hold as a screening method for asymptomatic patients at high risk of heart disease.

An open mind to the past may just be what the future needs.