For radiation oncology, a discipline very much driven by technology push, this will no doubt mean a bunch of equipment vendors getting even pushier with their wares. Such a scenario has elicited calls from some quarters for a more cohesive approach to technology assessment within the clinical community. The bone of contention is not new therapeutic technologies per se, rather the mechanisms for evaluating and optimizing those technologies in a structured, quantitative and rigorous manner.

In a scene-setting editorial in the latest issue of the "Red Journal", W Robert Lee, a radiation oncologist at Duke University School of Medicine (Durham, NC), reiterates the importance of due diligence when assessing new clinical technologies (Int. J. Radiat. Oncol. Biol. Phys. 70 652). "Newer is not necessarily better, and indeed may be worse," he argues, although sheer weight of numbers looks to be against him. While the US invests more than $100 billion every year on research, development and regulatory approval of new medical technologies, it spends less than $1 billion (0.05% of US healthcare spending) on the evaluation of those same technologies.

The question is, how do these rules of engagement affect clinical practitioners at the sharp end? A useful case study in this regard is proton therapy, an emerging treatment modality that's poised for a period of accelerated growth, with dozens of new facilities either planned or in the works. Writing in the same issue of the Red Journal, Michael Goitein, a senior medical physicist at Harvard Medical School (Boston, MA), confesses to finding it hard "not to be pleased about this growth" in proton therapy (Int. J. Radiat. Oncol. Biol. Phys. 70 654).

Like X-rays, protons kill cancer cells by ionization, which in turn damages cellular DNA. The attractiveness of protons stems from the fact that they deposit most of their energy at the end of their path with very little scattering on the way (the Bragg effect). This means that a proton beam can be tailored to dump the bulk of its "payload" in the tumour, rather than losing much of it in the healthy tissue it passes through on the way (as happens with X-rays).

If the underlying physics is clear enough, it's equally clear, argues Goitein, that "protons are not magical [and] the mere exposure to protons does not, in itself, doom proliferating malignant cells to their graves." His headline take is a cautionary one: put simply, proton therapy is not yet a mature technology and there are significant challenges - technical, clinical and financial - that need to be addressed before it can be considered the finished article.

On the technical front, for example, Goitein flags up "issues arising" with respect to beam penumbra, inhomogeneities, safety margins and process inefficiency (with treatment times double or more versus conventional radiotherapy). There are thorny financial pressures too - not least the potential use of oversimplified treatments to increase patient throughput; also the treatment of inappropriate patients. On a purely operational level, the roll-out of so many new proton facilities means demand for training will all too soon outstrip the bandwidth of current technical experts to supply it.

There are transferable lessons in all of this. While the concluding remarks in Goitein's argument refer specifically to protons, they look like a sensible reference point for the assessment of any new clinical technology. "Well used, protons have an enormous potential to improve our patients' lives," he writes. "That is why I wish to provoke the effort to strive for every bit of advantage that they can offer and to combat magical thinking - the fallacy that, just because they are protons, they will cure more patients (and make more money), no matter how they are used."