Market profile: liquid scintillation counters.

As a technique, liquid scintillation has remained essentially unchanged during the last 40 years, although the instruments have changed significantly. Certain materials, when exposed to radiation, emit pulses of UV light. Dissolved in a liquid sample and placed in a scintillation counter, these cocktail mixtures can help scientists measure levels of radioactivity. Fluors--special light-absorbing chemicals added to the liquid--convert the UV emissions into blue light, which is detected by the counter's two cathode photomultiplier tubes, or PMTs. Calculating the amplitude and frequency of these released photons, the PMTs generate electrical signals and, ultimately, display a measurement.

Breakthroughs in optics and photon-sensing electronics have corrected many of the background interference problems that plagued early models. Because modern liquid scintillation is so sensitive and is flexible to a high degree of specificity, the technique has become popular for tagging a wide array of proteins and peptides. Counters have been employed in clinical and research labs to measure growth hormones and drugs, bacterial and virus antigens, and genes and other biological substances.

The intricacies involved in setting up a scintillation counter have driven some users to newer technologies such as chromogenic, fluorescent and luminescent instruments. So too has the stigma and difficulty of handling radiological samples. Tritium, one of the isotope tags often used in counters, has a half life of more than 12 years and as such must be treated as radioactive waste. Manufacturers, in a bid to head off radiation concerns, stress the improved safety of their machines. Zinsser Analytic, for instance, promotes the solvents on which its aptly named Quicksafe scintillators are based as "nontoxic, biodegradable, odorless" and its scintillators themselves as "pleasant to use and easy to store and transport." Still, counter sales have not experienced any significant increase.

When PerkinElmer purchased Wallac in 1993 and Packard BioScience in 2001, it acquired the product lines of two of the world's leading scintillation counter manufacturers. Since then, although liquid scintillation growth has stagnated, PerkinElmer has held fast to its existing MicroBeta, TopCount and Tri-Carb models while shedding considerable portions of its other radioactivity business.

While this behavior might on the surface appear stubbornly nostalgic and counterintuitive to market suggestions, PerkinElmer is not unique among instrument companies. Beckman Coulter (which together with PerkinElmer makes up 80% of the market) and Amersham Biosciences--two instrument heavyweights--have significant resources invested in scintillation counters, and smaller companies like Raytest and Zinsser have offered their own models for decades.

One explanation for this consistency in demand is the relative inaccuracy of many nonisotopic assays. The use of nonisotope tags as replacements for radioimmunoassays has grown, but researchers cannot always obtain such assays for the substances they are testing. While newcomers are not likely to enter the business, existing suppliers are content to hold on to products that require minimal R&D and marketing. The total worldwide aftermarket and service estimate for liquid scintillation counters is estimated at $140 million for 2002. Overall growth is approximately 2.5% a year, with consumables offering slightly higher figures.

Liquid Scintillation At A Glance:

Leading Suppliers

* Beckman Coulter

* PerkinElmer

Instrument Cost

* $20k to $90k

Aftermarket

25% to 26% of total sales