Linear energy transfer characterization of five gel dosimeter formulations for electron and proton therapeutic beams.

Gel dosimeters, including radiochromic types like Fricke, as well as polymer formulations, are considered to be the only reliable option for accurate 3D dosimetry. Nevertheless, their implementation in daily clinical quality assurance still remains strongly limited for a few high specialized radiotherapy centres. Although gel dosimeters present very good water-equivalence due to their inherent chemical and isotopic compositions, addressing the corresponding dosimetry outputs is highly challenging, needing careful assessment in terms of the different radiation qualities involved in the mixed field. Accurate estimations of the linear energy transfer for each gel dosimeter formulation stands as a baseline for further accurate dose deconvolution in mixed radiation fields. The present study reports on the linear energy transfer characterization of five different gel dosimeter formulations, Fricke, Itabis, Magic, Nipam, and Pagat, for electron and proton therapeutic beams as obtained by Monte Carlo approaches, along with experimental results for validation purposes. The linear energy transfer, as a function of beam quality and penetration depth, is obtained for electron and proton therapeutic beams remarking the presence of non-negligible variations, which need to be accounted for a further accurate implementation of gel dosimetry as well as for precise dose deconvolution in mixed radiation fields.

The utility of the CES-D as a depression screening measure among low-income women attending primary care clinics. The Center for Epidemiologic Studies-Depression.

OBJECTIVE: Depressive disorders are among the most common medical disorders seen in primary care practice. The Center for Epidemiologic Studies-Depression (CES-D) scale is one of the measures commonly suggested for detecting depression in these clinics. However, to our knowledge, there have been no previous studies examining the validity of the CES-D among low-income women attending primary care clinics. METHOD: Low-income women attending public primary care clinics (n = 179, ages 20-77) completed the CES-D and the Diagnostic Interview Schedule for the DSM-IV (DIS-IV). RESULTS: The results supported the validity of the CES-D. The standard cut-score of 16 and above yielded a sensitivity of .95 and specificity of .70 in predicting Major Depressive Disorder (MDD). However, over two-thirds of those who screened positive did not meet criteria for MDD (positive predictive value = .28). The standard cut-score appears valid, but inefficient for depression screening in this population. An elevated cut-score of 34 yielded a higher specificity (.95) and over 50 percent of the patients who screened positive had a MDD (positive predictive value = .53), but at great cost to sensitivity (.45). CONCLUSION: Results indicated that the CES-D appears to be as valid for low-income, minority women as for any other demographic group examined in the literature. Despite similar validity, the CES-D appears to be inadequate for routine screening in this population. The positive predictive value remains very low no matter which cut-scores are used. The costs of the false positive rates could be prohibitive, especially in similar public primary care settings.

Socioeconomic status, ethnicity, and environmental tobacco exposure among non-smoking females.

This study examined the relationship between socioeconomic status (SES) and environmental tobacco smoke (ETS) exposure among non-smoking females, determined which SES variable(s) were most strongly associated with ETS exposure, and examined whether the relationship between SES and ETS exposure was the same for Blacks and Whites. Participants were 404 never-smoker females recruited in the community. Independent variables included income, education, occupation, median income within zip code of participants' residence, and ethnicity. Number of days per week exposed to ETS in the past year was the dependent variable. There was a significant correlation between CO levels (parts per million, ppm) and self-reported ETS exposure (r = 0.22, p < 0.001). The mean CO level exposure was 1.81 +/- 1.19 ppm, and the mean number of days per week of ETS exposure was 4.72 +/- 4.71. The most frequent source of ETS exposure was at public places (64.4%). Although Blacks tended to report higher ETS exposure than Whites (p = 0.08), this tendency disappeared when SES indicators were entered in the model. Correlations among SES indicators were either non-significant or very modest suggesting that different SES indicators may not measure the same construct. Education was the only SES variable that was significantly associated with ETS exposure in this population. The relationship between SES and ETS exposure was similar for both Blacks and Whites. These findings suggest that education may be the most important factor to be considered when designing interventions to decrease ETS exposure among young non-smoking females (e.g., public education of the hazards of ETS exposure and awareness of existing tobacco-control laws and regulations).

Prevalence of high-risk behaviors and obesity among low-income patients attending primary care clinics in Louisiana.

This study examined the prevalence of the most prominent high-risk behaviors that contribute to mortality in the United States (i.e., sedentary lifestyle, cigarette smoking, and high dietary fat intake) and obesity among low-income patients attending primary care clinics in Louisiana. The sample consisted of 1,132 patients attending primary care clinics that were randomly selected and administered a demographic questionnaire, the 1994 Behavioral Risk Factor Surveillance System, and the Eating Patterns Questionnaire. Participants consisted predominantly of African-American (67.7%), uninsured (73.3%), low-income, middle-aged females. Prevalence of high-risk behaviors included sedentary lifestyle (47.1%), cigarette smoking (26.2%), and high dietary fat intake (61.3%). Prevalence of obesity was 63.5%. In conclusion, low-income patients attending primary care clinics in Louisiana display a high frequency of important high-risk behaviors that contribute to mortality in this country. Obesity is also extremely prevalent in this population. Clinical implications and directions for future studies are discussed.

Alcoholism among indigent inpatients: identification and intervention by internal medicine residents.

BACKGROUND: This study examined alcoholism identification and interventions by internal medicine residents, determined the prevalence of alcoholism among indigent inpatients, and examined some variables related to alcoholism in this population. METHODS: The alcohol abuse and dependence section of the Diagnostic Interview Schedule was administered to 197 inpatients, and chart audits were done. RESULTS: The obtained prevalence of alcoholism was 17%. Residents identified current alcohol abuse among 71% of current alcoholics, 17% of past alcoholics, and 3% of nonalcoholics. Sixty-two percent of alcoholics identified by the residents did not receive advice or referral, 13% received advice, 17% were referred to Alcoholics Anonymous, and 8% were referred to an inpatient facility. CONCLUSIONS: Our results suggest that although residents' identification of alcoholism is satisfactory, it is necessary to improve their rates of intervention. The profile of the alcoholic inpatients in this study includes demographics, presence of chronic illnesses, and utilization of medical services as compared with nonalcoholics.