Water System Condition and Asset Replacement Prioritization

The goal of asset management is to identify and track the maintenance and replacement of assets that have reached their useful life. For that reason, gathering data and collecting information is a critical step when developing an asset management plan. Such data gathering includes physical and operational properties of the assets as well as collecting and tracking important events during the lifespan of the asset (i.e., pipe breaks, replacement year, maintenance performed, etc.). Critical factors in the asset management plan may be overlooked when there is no data or poor quality data. However, many utilities lack the resources for examining buried infrastructure and lack good quality work order data, so other methods of data collection are needed. The concept for this paper was to develop a means to acquire data on the assets for a condition assessment to identify pipes that were most likely to break and those with the highest consequences for same. Three utilities were used as examples. It was found that for buried infrastructure, much more information was known than anticipated but the actual predictions relied on only a few factors related to pipe type. However, there is a need to track the consequences, in this case breaks, which would indicate a failure. The latter would be useful for predicting future maintenance needs and the most at-risk assets, but is often missing in utility systems as many utilities do not adequately track breaks sufficiently. In this case two utilities were analyzed and predication on a third was developed.

Estimated additional lifetime risk of cancer attributable to diagnostic CT in a pediatric bone marrow transplant cohort: Experience at a single academic institution

Purpose: To determine the frequency of CT procedures in a cohort of bone marrow transplant patients and estimate the effective dose from each CT procedure as well as rough estimates of lifetime attributable risk (LAR) of cancer (both incidence and mortality). Background: Pediatric patients who undergo bone marrow transplant benefit greatly from the diagnostic power of computed tomography, but due to the need for frequent imaging, these patients are repeatedly exposed to the carcinogenic potential of ionizing radiation. Methods: CT Imaging and patient parameters were collected from a retrospective cohort of bone marrow transplant patients. Dosimetry was estimated as a function of age, dose length product (DLP), and scan region based on published DLP to effective dose tables. Lifetime attributable risk (LAR) of cancer as a function of age, gender, and organ specific dose was derived from BEIR VII phase 2 estimates. Results: 44 patients with bone marrow transplant were included and ranged in age from 7 months to 20 years (average age, 9 years). The average number of CT studies per patient was 3.2 over the 15 month period. The average effective dose for each study was 5.9 +/– 4.5 mSv. Cumulative effective dose to each patient was 20 +/– 32 mSv. It was estimated that in this cohort, the CT imaging performed over a 15-month period on a 64-slice scanner led to a lifetime additional risk of cancer incidence of 5 in 1000 and a lifetime additional risk of cancer mortality of 2 in 1000. Conclusion: Diagnostic CT is important in the assessment and management of ill patients following bone marrow transplant. The risk of ionizing radiation leading to additional development of cancer merits using as low a CT technique as reasonable to achieve a diagnostic study.