Performance Information and Innovation in the Canadian Government (Working Paper 43)

The presentation made at the conference addressed the issue of linkages between performance information and innovation within the Canadian federal government1. This is a three‐part paper prepared as background to that presentation. • Part I provides an overview of three main sources of performance information - results-based systems, program evaluation, and centrally driven review exercises – and reviews the Canadian experience with them. • Part II identifies and discusses a number of innovation issues that are common to the literature reviewed for this paper. • Part III examines actual and potential linkages between innovation and performance information. This section suggests that innovation in the Canadian federal government tends to cluster into two groups: smaller initiatives driven by staff or middle management; and much larger projects involving major programs, whole departments or whole-of-government. Readily available data on smaller innovation projects is skimpy but suggests that performance information does not play a major role in stimulating these initiatives. In contrast, two of the examples of large-scale innovation show that performance information plays a critical role at all stages. The paper concludes by supporting the contention of others writing on this topic: that more research is needed on innovation, particularly on its link to performance information. In that context, other conclusions drawn in this paper are tentative but suggest that the quality of performance information is as important for innovation as it is for performance management. However, innovation is likely to require its own particular performance information that may not be generated on a routine basis for purposes of performance management, particularly in the early stages of innovation. And, while the availability of performance information can be an important success factor in innovation, it does not stand alone. The commonality of a number of other factors identified in the literature surveyed for this paper strongly suggests that equal if not greater priority needs to be given to attenuating factors that inhibit innovation and to nurturing incentives.

CT Image Electron Density Quantification in Regions with Metal Implants: Implications for Radiotherapy Treatment Planning

In radiotherapy planning, computed tomography (CT) images are used to quantify the electron density of tissues and provide spatial anatomical information. Treatment planning systems use these data to calculate the expected spatial distribution of absorbed dose in a patient. CT imaging is complicated by the presence of metal implants which cause increased image noise, produce artifacts throughout the image and can exceed the available range of CT number values within the implant, perturbing electron density estimates in the image. Furthermore, current dose calculation algorithms do not accurately model radiation transport at metal-tissue interfaces. Combined, these issues adversely affect the accuracy of dose calculations in the vicinity of metal implants. As the number of patients with orthopedic and dental implants grows, so does the need to deliver safe and effective radiotherapy treatments in the presence of implants. The Medical Physics group at the Cancer Centre of Southeastern Ontario and Queen's University has developed a Cobalt-60 CT system that is relatively insensitive to metal artifacts due to the high energy, nearly monoenergetic Cobalt-60 photon beam. Kilovoltage CT (kVCT) images, including images corrected using a commercial metal artifact reduction tool, were compared to Cobalt-60 CT images throughout the treatment planning process, from initial imaging through to dose calculation. An effective metal artifact reduction algorithm was also implemented for the Cobalt-60 CT system. Electron density maps derived from the same kVCT and Cobalt-60 CT images indicated the impact of image artifacts on estimates of photon attenuation for treatment planning applications. Measurements showed that truncation of CT number data in kVCT images produced significant mischaracterization of the electron density of metals. Dose measurements downstream of metal inserts in a water phantom were compared to dose data calculated using CT images from kVCT and Cobalt-60 systems with and without artifact correction. The superior accuracy of electron density data derived from Cobalt-60 images compared to kVCT images produced calculated dose with far better agreement with measured results. These results indicated that dose calculation errors from metal image artifacts are primarily due to misrepresentation of electron density within metals rather than artifacts surrounding the implants.