Image quality assessment and medical physics evaluation of different portable dental X-ray units

Introduction: Recently developed portable dental X-ray units increase the mobility of the forensic odontologists and allow more efficient X-ray work in a disaster field, especially when used in combination with digital sensors. This type of machines might also have potential for application in remote areas, military and humanitarian missions, dental care of patients with mobility limitation, as well as imaging in operating rooms. Objective: To evaluate radiographic image quality acquired by three portable X-ray devices in combination with four image receptors and to evaluate their medical physics parameters. Materials and methods: Images of five samples consisting of four teeth and one formalin-fixed mandible were acquired by one conventional wall-mounted X-ray unit, MinRay (R) 60/70 kVp, used as a clinical standard, and three portable dental X-ray devices: AnyRay (R) 60 kVp, Nomad (R) 60 kVp and Rextar (R) 70 kVp, in combination with a phosphor image plate (PSP), a CCD, or a CMOS sensor. Three observers evaluated images for standard image quality besides forensic diagnostic quality on a 4-point rating scale. Furthermore, all machines underwent tests for occupational as well as patient dosimetry. Results: Statistical analysis showed good quality imaging for all system, with the combination of Nomad (R) and PSP yielding the best score. A significant difference in image quality between the combination of the four X-ray devices and four sensors was established (p < 0.05). For patient safety, the exposure rate was determined and exit dose rates for MinRay (R) at 60 kVp, MinRay (R) at 70 kVp, AnyRay (R), Nomad (R) and Rextar (R) were 3.4 mGy/s, 4.5 mGy/s, 13.5 mGy/s, 3.8 mGy/s and 2.6 mGy/s respectively. The kVp of the AnyRay (R) system was the most stable, with a ripple of 3.7%. Short-term variations in the tube output of all the devices were less than 10%. AnyRay (R) presented higher estimated effective dose than other machines. Occupational dosimetry showed doses at the operator`s hand being lowest with protective shielding (Nomad (R): 0.1 mu Gy). It was also low while using remote control (distance > 1 m: Rextar (R) < 0.2 mu Gy, MinRay (R) < 0.1 mu Gy). Conclusions: The present study demonstrated the feasibility of three portable X-ray systems to be used for specific indications, based on acceptable image quality and sufficient accuracy of the machines and following the standard guidelines for radiation hygiene. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

An integrative approach for studying the etiology of alcoholism and other addictions

Studies of alcoholism etiology often focus on genetic or psy-chosocial approaches, but not both. Greater understanding of the etiology of alcohol, tobacco and other addictions will come from integration of these research traditions. A research approach is outlined to test three models for the etiology of addictions — behavioral undercontrol, pharmacologic vulnerability, negative affect regulation — addressing key questions including (i) mediators of genetic effects, (ii) genotype-environment correlation effects, (iii) genotype x environment interaction effects, (iv) the developmental unfolding of genetic and environmental effects, (v) subtyping including identification of distinct trajectories of substance involvement, (vi) identification of individual genes that contribute to risk, and (vii) the consequences of excessive use. By using coordinated research designs, including prospective assessment of adolescent twins and their siblings and parents; of adult substance dependent and control twins and their MZ and DZ cotwins, the spouses of these pairs, and their adolescent offspring; and of regular families; by selecting for gene-mapping approaches sibships screened for extreme concordance or discordance on quantitative indices of substance use; and by using experimental (drug challenge) as well as survey approaches, a number of key questions concerning addiction etiology can be addressed. We discuss complementary strengths and weaknesses of different sampling strategies, as well as methods to implement such an integrated approach illustrated for the study of alcoholism etiology. A coordinated program of twin and family studies will allow a comprehensive dissection of the interplay of genetic and environmental risk-factors in the etiology of alcoholism and other addictions.

The validity of self-reported energy intake as determined using the doubly labelled water technique

In the 1980s the development of the doubly labelled water (DLW) technique made it possible to determine the validity of dietary assessment methods using external, independent markers of intake in free-living populations. Since then, the accuracy of self-reported energy intake (EI) has been questioned on a number of occasions as under-reporting has been found to be prevalent in many different populations. This paper is a review of investigations using the DLW technique in conjunction with self-reported EI measures in groups including adults, children and adolescents, obese persons, athletes, military personnel and trekking explorers. In studies where a person other than the subject is responsible for recording dietary intake, such as parents of young children, EI generally corresponds to DLW determined energy expenditure. However, in instances where the subjects themselves report their intake, EI is generally under-reported when compared with energy expenditure. It was originally believed that this phenomenon of under-reporting was linked to increased adiposity and body size, however, it is now apparent that other factors, such as dietary restraint and socio-economic status, are also involved. This paper therefore aims to present a more comprehensive picture of under-reporting by tying in the findings of many DLW studies with other studies focusing particularly on the characteristics and mechanisms for under-reporting. Awareness of these characteristics and mechanisms will enable researchers to obtain more accurate self-reports of EI using all dietary recording techniques.

Forced emigration, favourable outcomes

The discipline of public health and preventive medicine in Australia and New Zealand had its genesis in the advocacy of 18th and 19th century military pioneers. Military (Royal Navy and British Army) surgeons were posted to Australia as part of their non-discretionary duty. Civilian doctors emigrated variously for adventure, escapism and gold fever. One group, a particularly influential group disproportionate to their numbers, came in one sense as forced emigrants because of chronic respiratory disease in general, and tuberculosis in particular. Tuberculosis was an occupational hazard of 19th century medical and surgical practice throughout western Europe. This paper analyses six examples of such emigration which had, perhaps unforeseen at the time, significant results in the advancement of public health. Such emigration was in one sense voluntary, but in another was forced upon the victims in their quest for personal survival. In Australia, such medical individuals became leading advocates and successful catalysts for change in such diverse fields as social welfare, public health, the preventive aspects of medical practice, child health, nutrition and medical education. A number of such public health pioneers today have no physical memorials; but their influence is to be seen in the ethos of medical practice in Australia and New Zealand today. Their memory is further perpetuated in the names of Australian native wildflowers and trees that symbolise not only a healthy environment but the longterm investment, accrued with interest, of the institution of public health measures for which their advocacy achieved much success.

China and Southeast Asia

In the new millennium, no issue in international relations will be more important than how to accommodate the rising power of China. Many analysts, especially in the United States, see China as a significant threat to American interests in Asia. Washington has treaty commitments in both Northeast and Southeast Asia and retains a substantial military presence in the region. Beijing claims it does not seek to replace the United States reigning global hegemony, but seeks to promote a multi-polar world in which six states (the US, China, the EU, Russia, Japan, and India) would have pre-eminent status.

Holt, Johnson and the 1966 Federal Election. A Question of Causality

US President Lyndon Johnson's state visit to Australia in October 1966, came at the pinnacle of support for Australia's military involvement in the Vietnam War. Johnson's visit also occurred just weeks before an election for the House of Representatives at which the ruling Liberal-Country Party Coalition won its eighth successive, and largest victory, The proximity of these events has led many to argue that a causal relationship exists between the two. Advocates of this thesis, however, have failed to support their position with any evidence other than the anecdotal. Contrary to the assertions made by numerous political historians and observers of the period, this paper finds no evidence to support a thesis of causality. This paper argues that the Coalition's landslide victory in 1966 was both a rejection of the tired and lacklustre leadership of Labor's Arthur Calwell and a measure of the electorate's overwhelming support for Holt and his Government's policies of conscription and military involvement in Vietnam.

Jules Cotard (1840-1889) - His life and the unique syndrome which bears his name

Dr. Jules Cotard (1840-1889) was a Parisian neurologist who first described the delire des negations. Cotard's syndrome or Cotard's delusion comprises any one of a series of delusions ranging from the fixed and unshakable belief that one has lost organs, blood, or body parts to believing that one has lost one's soul or is dead. In its most profound form, the delusion takes the form of a professed belief that one does not exist. Encountered primarily in psychoses such as schizophrenia and bipolar disorder, Cotard's syndrome has also been described in organic lesions of the nondominant temporoparietal cortex as well as in migraine. Cotard's delusion is the only self-certifiable syndrome of delusional psychosis. Jules Cotard, a Parisian neurologist and psychiatrist and former military surgeon, was one of the first to induce cerebral atrophy by the experimental embolization of cerebral arteries in animals and a pioneer in studies of the clinicopathologic correlates of cerebral atrophy secondary to perinatal and postnatal pathologic changes. He was the first to record that unilateral cerebral atrophy in infancy does not necessarily lead to aphasia and was also the pioneer of studies of altered conscious states in diabetic hyperglycemia.

Nuclear weapons as obstacles to international security

This article argues that nuclear weapons serve no useful purpose in military calculations; moreover, their continued retention invites the dangers of further proliferation and of accidental use. They are thus defined here as obstacles to, rather than as facilitators of, international security. Seven reasons are presented to support this contention, including an assessment of the moral implications and the strategic limitations of nuclear weapons. Despite these limitations, and the recent commitments made by the nuclear weapon states to eliminate their arsenals, nuclear weapons remain central to the strategic doctrines of these states. Several reasons are put forward to explain why this retention continues, including the unchanging nature of strategic mindsets, the presence of vested interests, and now, in the case of the USA at least, a renewed reliance on nuclear weapons, regardless of how appropriate and effective such a strategy might be against emerging terrorist or `rogue state' threats.

Strange bedfellows: Green Hill Fort, archaeology and tourism

Green Hill Fort, Thursday Islalld was constructed between 1891-1893 to defend the Australian colonies against a feared Russian invasion. It retained an operational role until the 1920.'1 and played a minor role in World /t'ar 2. From 1954 to 1993 the site, but not the facilities, was used as a weather station. More recently it has been home ofthe Ton-es Strait Historical Society and Museum Association museum. It is a major attraction during the tourist season and an important local icon. For archaeologists it has sign~ficance as a relatively intact nineteenth-century military installation. Two 'Centenary of Federation' grants have proVided the impetus to undertake conservation and presentation works involving various task -spec~fic, archaeological activities. At the management level archaeologists play the lead role in the project. The project has demonstrated the value oJarchaeology and tourism joining forces. The danger ofa 'theme park 'presentation has been avoided. Technical accuracy and careful site planning has ensured a high degree ofaccuracy is retained. Provided these qualities can be assured then, it is argued, there is an opportunity for archaeology to be a majOl; long-term beneficiary. But to achieve that, the discipline must move from being entrenched in its academic mould and become Jar more receptive to the broader needs ofthe twentyfirst century.

Further evidence for the agreement between patients with stroke and their proxies on the Frenchay Activities Index

Objective: To determine item, subscale and total score agreement on the Frenchay Activities Index (FAI) between stroke patients and proxies six months after discharge from rehabilitation. Design: Prospective study design. Setting/subjects: Fifty patient-proxy pairs, interviewed separately, in the patient's residence. Main outcome measures: Modified FAI using 13 items. Individual FAI items, subscales and total score agreement as measured by weighted kappa and intraclass correlation coefficients (ICC). Results: Excellent agreement was found for the total FAI (ICC 0.87, 95% confidence interval (CI) 0.78-0.93), and domestic (ICC 0.85, 95% CI 0.73-0.91) and outdoor (ICC 0.87, 95% CI 0.78-0.95) subscales, with moderate agreement found for the work/leisure subscale (ICC 0.63, 95% CI 0.34-0.78). For the individual FAI items, good, moderate, fair and poor agreement was found for five, three, four and one item, respectively. The best agreement was for objective items of preparing meals, washing-up, washing clothes, shopping and driving. The poorest agreement was for participation in hobbies, social outings and heavy housework. Scoring biases associated with patient or proxy demographic characteristics were found. Female proxies, and those who were spouses, scored patients lower on domestic activities; male patients, and those who were younger, scored themselves higher on outdoor activities and higher patient FIM scores were positively correlated with higher FAI scores. Conclusions: While total and subscale agreement on the FAI was high, individual item agreement varied. Proxy scores should be used with caution due to bias.

America's nuclear deterrence in the age of terrorism

The September 11, 2001 terrorist attacks in the US and the leakage of the Nuclear Posture Report (NPR) spur a complete review of the nuclear doctrine under Pres George W. Bush's administration. Kampmark discusses the contrariness of NPR in relation to America's deterrence of nuclear weapons and the possible proliferation of tactical offensive weapons as compared to strategic nuclear weapons.