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A novel automatic method of segmenting nevi is explained and analyzed in this paper. The first step in nevi segmentation is to iteratively apply an adaptive mean shift filter to form clusters in the image and to remove noise. The goal of this step is to remove differences in skin intensity and hairs from the image, while still preserving the shape of nevi present on the skin. Each iteration of the mean shift filter changes pixel values to be a weighted average of pixels in its neighborhood. Some new extensions to the mean shift filter are proposed to allow for better segmentation of nevi from the skin. The kernel, that describes how the pixels in its neighborhood will be averaged, is adaptive; the shape of the kernel is a function of the local histogram. After initial clustering, a simple merging of clusters is done. Finally, clusters that are local minima are found and analyzed to determine which clusters are nevi. When this algorithm was compared to an assessment by an expert dermatologist, it showed a sensitivity rate and diagnostic accuracy of over 95% on the test set, for nevi larger than 1.5mm.

Novel nondestructive method based on low coherence optical interferometry for measurement of deep etched trenches in MEMs structures is presented. The proposed technique proves to provide very reproducible results and can be easily extended to metrology of other materials such as metals and dielectrics. We present results in real life semiconductor structures and discuss practical and fundamental limits of this technique

Skin cancer is the most common malignancy in humans [1]. Furthermore, Armstrong and Kricker [2] have calculated that in white populations over 90% of cutaneous malignant melanomas are caused by sun exposure. Similar proportions of both basal cell carcinoma and squamous cell carcinoma of the skin are likely attributable to sunlight exposure [3]. Because of the high proportion of skin cancer caused by sunlight, prevention programs have become increasingly common not only in high incidence areas such as Australia [4,5], but also in lower incidence countries such as Canada [6], the US [7,8] and the UK [9].

It is highly desirable to identify malignant melanoma, a common cancer, at an early stage. One important clinical feature of this cancer is asymmetrical skin lesions. In this paper, we propose an adaptive fuzzy approach that uses symmetric distance (SD) to measure lesions with fuzzy borders. The use of a number of SD variations and the adoption of a backpropagation neural network enhances the discriminative power of the approach. Digitized images from the Lesion Clinic in Vancouver, Canada, demonstrate the accurate classification of asymmetric lesions at around 80%.

We present an algorithm to identify skin lesions from the digitized colour images collected in a clinical study of malignant melanomas in early 1994. The algorithm consists of three steps: (1) a multi-stage median filter to suppress noise, (2) a process to compute the threshold values for the lesions and the background normal skin, and (3) a rule-based system to identify the lesions. Trying to make full use of the colour information, the first two steps of the algorithm work on the RGB planes. Then the three colour planes are re-combined before the lesions are identified in the last step.

One of the important clinical features to differentiate benign melanocytic nevi from malignant melanomas is the irregularity of the lesion border. A careful examination of a lesion border reveals two types of irregularity: texture irregularity and structure irregularity. Texture irregularities are the small variations along the border, while structure irregularities are the global indentations and protrusions, which may suggest excess of cell growth or regression of a melanoma. Therefore, measuring border irregularity by structural indentations and protrusions may detect the malignancy of the lesion. The common shape descriptors such as compactness index and fractal dimension are more sensitive to texture irregularities than structure irregularities. They do not provide an accurate estimation for the structure irregularity. Therefore, we have designed a new measurement for border irregularity. The proposed method first locates all indentations and protrusions along the lesion border. Then a new area-based index, called irregularity index, is computed for each indentation and protrusion. The overall border irregularity is estimated by the sum of all individual indices. In addition, the new method offers an extra feature: localization of the significant indentations and protrusions. As the result, the new measure is sensitive to structure irregularities and may be useful for diagnosing melanomas.

This paper presents an automatic computer system for analyzing the structural shape of cutaneous melanocytic lesion borders. The computer system consists of two steps: pre-preprocessing the skin lesion images and lesion border shape analysis. In the preprocessing step, the lesion border is extracted from the skin images after the dark thick hairs are removed by a program called DullRazor. The second step analyzes the structural shape of the lesion border using a new measure called sigma-ratio. The new measure is derived from scale- space filtering technique with an extended scale-space image. When comparing the new measure with other common shape descriptors, such as compactness index and fractal dimensional, sigma-ratio is more sensitive to the structural protrusions and indentations. In addition, the extended scale- space image can be used to pinpoint the locations of the structural indentations and protrusions, the potential problem areas of the lesion.

Estimating the Economic Burden of Inflammatory Bowel Disease in Canada: Physician Office Visits and Mesalamine Prescriptions Dispensed as Surrogate Markers

Background: Evaluating the incidence of nonmelanocytic skin cancers in white populations and assessing the direction and strength of secular trends in these cancers have become important issues to dermatologists, oncologists, health policy analysts, and health care funders. Objective: The objective of this paper is to evaluate the three principal methods used to assess incidence rates and secular trends. Conclusions: Each of the three methods has strengths and weaknesses. An understanding of these will enable proper assessment of the value and significance of findings presented in the literature.

Over 3 million new cases of skin cancer are diagnosed in the US annually. Melanoma, a subtype of skin cancer that can be fatal if the disease is not detected and treated at an early stage, is the most common cancer for those aged 25-29 years and the second most common cancer in adolescents and young adults aged 15-29 years. The primary carcinogen for the genesis of skin cancers is ultraviolet light from solar radiation and tanning beds. In spite of massive health campaigns to raise public awareness on ultraviolet radiation, sun-protective practices still fall behind. A plausible explanation is the lack of behavioral change in the populations at risk; in this review article, we examine sun-protective behavior in the four high-risk skin cancer groups: skin cancer survivors, individuals with a family history of melanoma, individuals with physical characteristics associated with skin cancer risk, and organ transplantation patients. Findings in the literature demonstrate that increased knowledge and awareness does not consequently translate into behavioral changes in practice. Behavior can differ as a result of different attitudes and beliefs, depending on the population at risk. Thus, intervention should be tailored to the population targeted. A multidisciplinary health team providing consultation and education is required to influence these much needed changes.

Malignant melanoma is the most common cancer in people less than 35 years of age and incident rates are increasing by approximately 5 percent per annum in many white populations, including British Columbia, Canada. In 1994, a clinical study has been established to digitize melanocytic lesions under a controlled environment. Lesions are digitized from patients who are referred to the Colored Pigment Lesion Clinic in the University of British Columbia. In this paper, we investigate how to use fractal dimensions (FDs) in measuring the irregularity of a skin lesion. In a previous project, we have experimented with 6 different methods to calculate fractal dimensions on a small number of images of skin lesions, and the simple box-counting method performed the best. However, the method did not exploit the intensity information of the images. With the new set of images which are digitized under the controlled environment, we utilize the differential box counting method to exploit such information. Four FD measures, including the direct FD, the horizontal and the vertical smoothing FDs, and the multi- fractal dimension of order two, are calculated based on the original color images. In addition, these 4 FD features are repeatedly calculate for the blue band of the images. This paper reports the different features through the calculations of the fractal dimensions and compares their differentiation power in the use of diagnosis of images of skin lesions.

In order to evaluate risk factors for germ cell cancers, we conducted a case-control study of 510 men with testicular cancer aged 15 to 79 years and 996 randomly selected age-matched controls in the provinces of British Columbia and Alberta, Canada. Subjects completed a mailed questionnaire providing data on education level, ethnic origin, medical history, smoking, occupation, and recreational and sports activity. The response rate among cases was 80.3 percent and among controls was 68.1 percent. After controlling for age and ethnic origin, undescended testis was associated positively with risk of testicular cancer (odds ratio [OR] = 3.5; 95 percent confidence interval [CI] = 2.2-5.7) as was inguinal hernia requiring surgery (OR = 2.0, CI = 1.3-2.9), and hydrocoele (OR = 2.6, CI = 1.4-5.1). Risk of testicular cancer increased with height, with subjects taller than 180 cm having a significantly increased risk compared with those 174 cm or less (OR = 1.5, CI = 1.1-2.1). A moderate to high level of recreational activity level was associated inversely with testicular cancer risk (OR = 0.6, CI = 0.5-0.8).

A simple physical zone model was developed to explain the formation of polychromatic speckle patterns within the Fresnel region. This model represents a reasonable compromise between complex theoretical formulation and simple estimations for practical needs, and allows the speckle contrast to be calculated as a function of geometric parameters for the optics and coherence length of the light source. The model was experimentally verified, and the results are consistent with our previous rigorous theoretical formulation.

ContextHigh nevus density is a risk factor for cutaneous malignant melanoma. Melanocytic nevi originate in childhood and are largely caused by solar exposure.ObjectiveTo determine whether use of broad-spectrum, high–sun protection factor (SPF) sunscreen attenuates development of nevi in white children.DesignRandomized trial conducted June 1993 to May 1996.Setting and ParticipantsA total of 458 Vancouver, British Columbia, schoolchildren in grades 1 and 4 were randomized in 1993. After exclusion of nonwhite children and those lost to follow-up or with missing data, 309 children remained for analysis. Each child's nevi were enumerated at the start and end of the study in 1996.InterventionParents of children randomly assigned to the treatment group (n=222) received a supply of SPF 30 broad-spectrum sunscreen with directions to apply it to exposed sites when the child was expected to be in the sun for 30 minutes or more. Children randomly assigned to the control group (n=236) received no sunscreen and were given no advice about sunscreen use.Main Outcome MeasureNumber of new nevi acquired during the 3 years of the study, compared between treatment and control groups.ResultsChildren in the sunscreen group developed fewer nevi than did children in the control group (median counts, 24 vs 28; P=.048). A significant interaction was detected between freckling and study group, indicating that sunscreen use was much more important for children with freckles than for children without. Modeling of the data suggests that freckled children assigned to a broad-spectrum sunscreen intervention would develop 30% to 40% fewer new nevi than freckled children assigned to the control group.ConclusionsOur data indicate that broad-spectrum sunscreens may attenuate the number of nevi in white children, especially if they have freckles.

Several older epidemiologic studies have suggested that exposure to polychlorinated biphenyls (PCBs) may increase risk of cutaneous malignant melanoma (CMM). These investigations, however, have not been able to control for sun exposure, and sun sensitivity, which are major risk factors for this cancer. We conducted a pilot study to examine the possible association between plasma levels of PCBs and risk of CMM, controlling for sun exposure and sun sensitivity. Our case-control study compared levels of 14 PCB congeners in the plasma of 80 Caucasian CMM patients, and 310 Caucasian controls frequency matched by age group and gender. Assays were conducted using gas chromatography and values were lipid-adjusted. Data concerning sun exposure history, sun sensitivity, and host pigmentation variables such as skin, eye and hair colour were also collected using standardized questionnaires. Odds ratios and 95% confidence intervals were calculated for total PCBs, dioxin-like and non-dioxin like PCBs, as well as individual congeners using unconditional logistic regression. A strong association was seen between melanoma risk and plasma levels of total PCBs, (OR highest quartile: 6.02; 95% CI = 2.00-18.17); non-dioxin-like PCBs (OR highest quartile:7.02; 95%CI = 2.30-21.43); and many of the single congeners. These associations persisted after adjustment for recreational sun exposure, sun sensitivity and pigmentation factors. Although the study results will require independent confirmation in larger case-control or cohort investigations, they suggest that potential environmental factors other than UV radiation may be involved in melanoma.