Admittedly, delegate numbers are a fairly crude indicator of a technology's prospects (the weather and golf in St Petersburg being hard to beat this time of year). However, a new study from US consultancy IMV provides a more solid quantitative take on the rapid adoption of IGRT technologies into clinical practice.
"While the number of patients treated with radiation therapy every year is relatively stable, the technological sophistication of radiation-oncology departments is continuing to advance," explained Lorna Young, IMV's senior director, market research.
"Digital imaging has become integrated into treatment planning and to guide tumour treatment in real-time," she continued. "While in 2004, 15% of the radiation-oncology sites provided IGRT in their department, over one-third of the sites do so now, using either a dedicated IGRT imaging device or electronic-portal imaging. Ultrasound, X-ray and CT are the primary imaging modalities used in IGRT."
More generally, IMV estimates that patients made around 23.2 million radiation-therapy or related visits in the US last year. That total comprised 19 million treatment visits and 4.2 million allied visits (i.e. non-treatment activities like consultation, treatment planning and follow-up). The top three cancer sites in terms of treatment were found to be breast, prostate and lung - accounting for 21%, 20% and 12% respectively of all cancer sites treated using radiation therapy.
Young told medicalphysicsweb that the proportion of radiation-oncology sites having at least one type of IGRT capability (X-ray, CT, ultrasound) may well rise to 50% over the next three years. "CT and X-ray IGRT configurations will comprise over 80% of future installations, based on purchase plans indicated by respondents. [Right now], these two modalities comprise nearly 60% of the total IGRT installed base," she explained.
The IMV study found that 90% of the radiation-therapy sites surveyed use networks for sharing images used in treatment planning. "The radiation-oncology department has lagged radiology in the adoption of electronic archive and communication technology," Young explained. "For trend watchers, this stat confirms that networking and electronic image archive has come of age."
The report notes that CT systems comprised over 80% of the simulators installed for treatment planning in 2006. Currently, says Young, the overall simulator installed base is 50% CT, 49% X-ray and 1% PET/CT. "The prior technology that dominated was X-ray simulators. The 2006 figure confirms the trend towards using CT simulator technology."
Also significant is the proportion of radiation-oncology sites having capital-equipment budgets of more than $1.5 million: up from 15% of the sites surveyed in 2003 to 33% of sites in 2007.
• See also: Why IGRT needs a common language on medicalphysicsweb.