To establish whether CT dose variation occurs in breast cancer localization procedures between radiation therapy (RT) centres in Ireland and to propose diagnostic reference levels (DRLs) for this ...procedure.
All RT centres in Ireland were invited to participate in a dose audit survey, providing data on the CT dose index volume (CTDIvol), dose-length product (DLP), current-time product (mAs), tube potential, scan length, slice thickness, scanning margins, use of automated exposure control (AEC) and scanner technology for 10 patients with breast cancer who were average sized. DRLs were derived for each dose descriptor by calculation of the rounded 75th percentile of the distribution of mean doses.
Data were returned for 60 patients from 6 RT centres (50% response rate). Significant variation in mean CTDIvol and mean DLP was observed between centres (p < 0.0001). Mean scan lengths and mean mAs differed significantly between centres (p < 0.0001). Tube potential was 120 kV for all sequences across centres. AEC was employed in all but one centre. Proposed DRLs for breast localization are 26 mGy and 732 mGy cm for CTDIvol and DLP, respectively.
CT dose variation occurs between centres, establishing a need for optimization. DRLs for breast cancer localization have been proposed with the potential for reduction in CT dose.
This article provides the first reported DRL for breast cancer CT localization procedure in RT and can be used as a benchmark for comparison for other RT centres.
Central to this research paper are findings from a major international collaborative study into the social and economic impact of the World Rally Championship (WRC) during 2007. Scholarship in the ...field of motorsport is rare, which is remarkable against the backdrop of a discipline that has truly global appeal. The analysis contained herein unfolds within extant research into the staging of so-called 'mega' sports events but highlights important shortcomings in this literature when examining a sport, such as rallying, which takes place beyond the normal sporting boundaries. The study also engages in debates surrounding the role of sport as an agent for social and cultural regeneration but advances a number of inadequacies within this and other procedures involved in measuring the full impact major sports events exercise upon their host communities. Beyond this a study of the WRC in 2007 reminds the reader of how sport events have differing symbolic significance depending upon the national political and cultural locales in which they take place. In this regard this essay also unpacks established discourses surrounding sporting legacy, exactly what constitutes a 'sport tourist' and the vexed issue of the use of multipliers when calculating the full economic impact of sports events both now and in the future.
Background: Human alcohol self‐administration studies employing oral intake are subject to high variability of the resulting blood alcohol concentrations because of idiosyncrasies of ...gastrointestinal absorption kinetics among subjects. We sought to improve the subjects’ opportunity to control their brain alcohol exposure by computer‐assisted i.v. self‐administration.
Methods: Instead of drinking, subjects could request increments of their arterial blood alcohol concentration (aBAC) of precisely 7.5 mg% at any time they wanted by pressing a button, provided their aBAC would not exceed 100 mg%. The latency between pushing the button and reaching the new aBAC peak was preset to be 2.5 minutes on the first day and was randomly changed to 1.5 or 3.5 minutes on days 2 and 3 in a crossover design. The necessary rate and amount of alcohol infusion was calculated by the software about once every second. Nine healthy social drinkers (4 females/5 males; mean age 25.0 ± 4.0 year) participated in 3 sessions each. Outcome measures were mean and maximum observed aBAC, and the number of alcohol requests.
Results: Maximum aBAC was 76.5 ± 26.3 mg% on average over all experiments. When grouping days 2 and 3 according to latency (1.5 vs. 3.5 minutes), maximum aBAC and the number of requests in the session were significantly higher with the faster rise and all 3 outcome measures were significantly correlated between days. No such correlations were found between the first and either of the following days.
Conclusions: These data suggest that CASE is practical and safe, and results in considerable alcohol exposure that can be manipulated with parameters chosen for the incremental exposure. Following 1 practice day, test–retest stability was good, suggesting a potential for use in scientific studies.
Background: The differentiator model predicts that individuals with a positive family history of alcoholism (FHA) or heavy alcohol consumers will feel more sensitive to the effects of alcohol on the ...ascending phase of the blood alcohol content while feeling less sedated on the descending phase. This study tested whether subjective perceptions are sensitive to the slope of breath alcohol concentration (BrAC) and whether that sensitivity is associated with an FHA and/or recent drinking history (RDH).
Methods: Family‐history‐positive (FHP, n = 27) and family‐history‐negative (FHN, n = 27) young adult nondependent drinkers were infused intravenously with alcohol in 2 sessions separated by 1 week. After 20 minutes, one session had an ascending BrAC (+3.0 mg%/min), while the other session had a descending BrAC (−1 mg%/min). The BrAC for both sessions at this point was approximately 60 mg%, referred to as the crossover point. Subjective perceptions of intoxication, high, stimulated, and sedation were sampled frequently and then interpolated to the crossover point. Within‐subject differences between ascending and descending responses were examined for associations with FHA and/or RDH.
Results: Recent moderate drinkers reported increased perceptions of feeling intoxicated (p < 0.023) and high (p < 0.023) on the ascending slope compared with the descending slope. In contrast, recent light drinkers felt more intoxicated and high on the descending slope.
Conclusions: Subjective perceptions in young adult social drinkers depend on the slope of the BrAC when examined in association with RDH. These results support the differentiator model hypothesis concerning the ascending slope and suggest that moderate alcohol consumers could be at risk for increased alcohol consumption because they feel more intoxicated and high on the ascending slope. Subjects did not feel less sedated on the descending slope, contrary to the differentiator model but replicating several previous studies.
Background:
The mesolimbic dopaminergic system is thought to mediate alcohol abuse and dependence. Determining the relationship between in vivo dopamine and the subjective response to alcohol could ...improve understanding of the mechanisms that lead to alcohol abuse and dependence. Here, we examined the relationship between dopamine D2 receptors in the nucleus accumbens and scores of perceived “high” and “intoxication” during an intravenous (IV) alcohol infusion.
Methods:
Nine healthy control subjects received 11Craclopride PET scanning at baseline. Eight subjects received a second 11Craclopride scan during a pharmacodynamically modeled and controlled rise of IV alcohol, followed by steady state (60 mg%± 5 mg%) alcohol infusion. Numerical ratings of “high” and “intoxication” were tested for correlations with measures of dopaminergic function.
Results:
Baseline D2 receptor availability in the left nucleus accumbens was significantly correlated with peak perceived “intoxication” (p= 0.02) and marginally correlated with peak perceived “high” (p= 0.07).
Conclusions:
Resting D2 receptor availability may predict healthy subject responses to alcohol exposure.
Two procedures are described for the detection of inhibitors of angiotensin converting enzyme (ACE). The first is a new agar-plate method useful as a screening tool. Two ACE inhibitors produced by ...culture A58365 were discovered using this plate test. The second method is a modification of a previously reported spectrophotometric procedure. Both procedures utilize p-nitrobenzyl-oxycarbonylglycyl-(S-4-nitrobenzo-2-oxa-1, 3-diazole)-L-cysteinylglycine as substrate.
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