Consider the Dose

Health care providers have a responsibility to their patients to ensure strict adherence to the international guiding principle “as low as reasonably achievable” for radiation safety. Nurses can pledge their support for this concept and lead through education on radiation safety. We can become radiation cognizant and educate health care professionals on the doses patients receive during computed tomography examinations. This will aid health care providers in deciding the risks and benefits of these exams.     

Low Dose Epilation by Alexandrite Laser: A Dose Response Study

Theoretical considerations suggest fluences of 10 J/cm2 to be sufficient for hair growth control by photo epilationwithalexandrite laser. To prove this hypothesis for clinical applications a dosimetry study was performed with fluences of 5, 10, 15 and 20J/cm2 with an alexandrite laser (burst pulse, 7 ms pulse width, 9 mm spot size) in 14 volunteers. The regrowth rate of hair was calculated on the basis of digital hair counts on comparable test sides in different body locations (back, legs, abdomen, upper arms).In all 4 fluence groups similar rates of hair loss were reached in short term epilation. After an average number of 4,9 treatments (range 2–8 treatments) alexandrite laser treatment with 5 J/cm2 achieved 70,5% hair loss, with 10 J/cm2 74,2%, with 15 J/cm2 85,1% and 20 J/cm2 resultedin 80,1%.In preliminary results after a six months follow up the hair loss remained constantly at 56% within the 5 J/cm2 field and showed still increase in hair loss in the 15 and 20 J/cm2 fields, the latter reaching 81%. Only the 10 J/cm2 field showed a slight regrowth (5%). The differences between the results of hair loss in these 4 fluence groups of 56%(5 J/cm2 fields) or 62% (10 J/cm2 field) versus 74% (15 or 20 J/cm2 fields) were not statistically significant. These data suggest a sufficient hair reduction of more than 70% being achieved after at least 4 treatments with low fluences of 5 or 10 J/cm2 of an alexandrite laser. The lower fluences (5 and 10 J/cm2) caused no pain during the photo epilation and had no side effects. The over all treatment was rather quick in performence with below mentioned fluences. Though the long term results of this study are still preliminary low fluences show comparable efficacy to treatments using higher fluences. Ahigher number of follow up cases could prove that lowdose epilation is also effective in terms of long lasting results.     

Radiation Exposure Dose Trends and Radiation Dose Reduction Strategies in Medical Imaging

Since the discovery of x-rays, many investigations of radiation effects on humans have taken place. From the discovery of severe x-ray dermatitis near the end of 1896, the multiple radiation burns endured by Thomas Edison's assistant, Clarence Dally, to the establishment of early radiation regulation in 1929, radiation exposure has been a continuing concern. Studies from the 1940s to the 1960s looked at effects such as leukemia and other cancers that appeared to be caused by exposure to radiation; outcomes of these studies resulted in increased regulation, establishment of dose tolerances and the development of the National Council on Radiation Protection (NCRP). Since the 1960s, similar studies have continued resulting in stricter dose limits. However, a recent resurgence of radiation exposure injuries led to this literature review that revealed a gap in the literature concerning the radiation practices and continued education of today's radiologic technologists. Through this review, recommendations for dose reduction strategies are included.     

The Thermal Dose Index

Objective. A new index is proposed to help sonographers easily assess the risk of an adverse thermal effect arising from a clinical examination. It is called the thermal dose index (TDI). Methods. The TDI uses the familiar thermal index (TI) and the examination duration to compute a dimensionless index. Results. The greater the TDI value, the greater the risk of a thermally induced adverse effect. If the TDI is 1 or less, there is no expectation of a thermally induced adverse effect. Conclusions. Like the TI, the TDI would be a convenient index that is continually updated and displayed during an ultrasound examination. The TDI is a new estimate of thermal risk that takes into account the duration of an ultrasound examination.     

Nurse Dose as a Concept

PURPOSE: To describe the concept of Nurse Dose. METHODS: The concept of nurse dose has been identified from decades of clinical research as a concept essential in the delivery of safe and high quality health care. The components of nurse dose were conceptualized through review of the literature from nursing, medicine, and health services research. FINDINGS: Nurse dose is conceptualized as having three equally essential components: dose, nurse, and host and host response. Dose in the macro view includes the number of nurses per patient or per population in cities, states, regions, or countries. Dose in a micro view includes the amount of nurse time and the number of contacts. The nurse component consists of the education, expertise, and experience of the nurse. Host is represented by an organization and its characteristics (culture, autonomy, practice control) in a macro view and by the patient and characteristics (beliefs, values, culture) in a micro view. Host response includes response to the autonomy and acceptability of the nurse. CONCLUSIONS: Greater nurse dose has been associated with decreases in patient mortality, morbidity, and healthcare costs.     

Dose of case management interventions

Case management programs need to be evaluated for outcomes achievement and efficient use of resources. As a provider intervention, case management is interactional and situational. Little is known about how to measure the actual dose delivered in order to assess quality and manage outcomes. Case management is interdisciplinary, has identifiable dimensions, and serves as a practical example of conceptualizing and measuring the dosage of a provider's intervention. The basic elements of the dosage of an intervention are amount, frequency, duration, and breadth. A three-dimensional model illustrates dosage of case management.     

A Delicate Dose of Humor

This article explores the uses and effects of humor in the practice and teaching of nursing. Various situations are discussed to highlight the positive and negative effects of humor on the nurse-client relationship. Observations are made regarding the use of humor in the learning environment. Humor is also discussed in relation to professional role socialization. Overall, a case is made to legitimize humor as a valuable therapeutic and teaching tool.     

The Livingston Paediatric Dose Calculator

The Livingston Paediatric Dose Calculator is presented and its use explained. It may be of benefit in emergency departments that do not regularly see large numbers of children requiring drug treatment.     

Acoustic Dose and Acoustic Dose-Rate

Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Expressions for acoustic dose and acoustic dose-rate are given for plane-wave conditions, including temporal and frequency dependencies of energy deposition. The relationship between the acoustic dose-rate and the resulting temperature increase is explored, as is the relationship between acoustic dose-rate and radiation force. Energy transfer from the wave to the medium by means of acoustic cavitation is considered, and an approach is proposed in principle that could allow cavitation to be included within the proposed definitions of acoustic dose and acoustic dose-rate. (E-mail: f.duck@bath.ac.uk)     

Increasing the Dose of Varenicline in Patients Who Do Not Respond to the Standard Dose

Varenicline is a partial agonist of α4β2 nicotinic acetylcholine receptors. It is effective at dosages of 2 mg/d for 12 weeks, but not for all smokers. It is possible that increasing the dose can increase the drug efficacy. We reviewed the clinical records of consecutive smokers who had been treated in 2 smoking cessation services with varenicline at doses of 3 mg/d. In all cases, the treatment program consisted of a combination of behavioral therapy and drug treatment. Varenicline was prescribed at a standard dosage for 8 weeks. After 8 weeks of treatment, the dose was increased to 3 mg/d if patients tolerated varenicline well and continued smoking or, in spite of not smoking, if they experienced severe withdrawal symptoms. The sample included 73 patients, of whom 52 continued to smoke at 8 weeks and 21 stopped smoking but reported severe withdrawal discomfort. Carbon monoxide-validated continuous abstinence rates from week 9 to week 24 were 40% and 48% in these 2 subgroups, respectively. The increase in dosage was associated with adverse events in 22 patients (30%). These were mostly mild and included nausea, vomiting, abnormal dreams, and insomnia. Only 2 patients discontinued treatment (both because of nausea and vomiting). Thus, we conclude that increasing the varenicline dose in smokers who do not respond to the standard dose after 8 weeks of treatment is associated with limited adverse events and high success rates.     

Dose reduction methods for CT colonography

Patients, referring physicians, the media, and government agencies have all expressed concern over the risks of medical radiation, particularly as it relates to CT. This concern is particularly paramount when associated with a screening examination such as CT colonography. These theoretical risks must be weighed realistically against the substantial benefits of colon cancer screening as well as against the risks inherent in the major alternative screening option, optical colonoscopy. When put into perspective, the risk–benefit ratio is highly in favor of the performance of CT colonography. Nevertheless, in following the ALARA principle, there is an ever increasing armamentarium of options that can be employed in the pursuit of CT radiation dose reduction, all of which can be used in many synergistic combinations allowing for dose reduction while simultaneously preserving image quality and minimizing image noise. After a brief tutorial on estimating radiation dose, various strategies will be discussed including reductions in tube current and tube voltage as well as the use of automatic dose modulation and iterative reconstruction. Other practical considerations will also be reviewed including proper patient isocentering, optimization of colonic insufflation to minimize additional decubitus scans, proper choice of scan volumes to avoid overranging, and variation of slice thickness and window width to minimize perceived image noise. Finally, a strategy for how to incrementally introduce these methods as well as a way to compare dose reduction efforts across institutions throughout the country will be offered.     

Measuring the Dose of Nursing Intervention

PURPOSE: To increase awareness of the many issues involved in measuring the dose of nursing intervention in nursing interventions effectiveness research. METHODS: Identify critical issues in measurement of the dose of nursing intervention and discuss decisions regarding dosage measurement made in a study of the effectiveness of nursing interventions. FINDINGS: A single method can be applied to resolve two critical issues in intervention dosage measurement. CONCLUSIONS: Those conducting nursing interventions effectiveness research must think explicitly about how intervention dosage will be measured and reported so that dosage can be replicated in research and practice. PRACTICE IMPLICATIONS: Measuring and reporting the dose of nursing intervention in research is essential to the development of an evidence base adequate to support practice.     

Dose dependency of furosemide-induced sodium excretion

Intravenous furosemide doses ranging from 5 to 120 mg were given to healthy young volunteers with and without individualized active rehydration with a sodium chloride solution. Sodium excretion rates and fractional sodium excretions (FENa) percentages were correlated significantly with dose and with urinary excretion rates of furosemide. The ED50 was below 5 mg and no additional natriuretic effect was seen above 40 mg. The efficiency (FENa percentage per microgram of furosemide excreted per minute during a certain clearance period) was dependent on hydration and on time. For the period 15 to 30 min a significant linear relationship between furosemide dose and the reciprocal of the efficiency indicated a higher efficiency for lower doses and a theoretical maximal value of FENa of 0.4% per micrograms of furosemide excreted per minute. A relative value for a dose-dependent efficiency reduction was calculated for each dose. The ED50 for dose-dependent efficiency reduction was about 12 mg i.v. Simultaneous measurements of lithium clearance indicated a proximal site of action for furosemide which was saturated at furosemide excretion rates above 50 micrograms/minute. For the major, distal, site of action no maximal value was demonstrated. It is concluded that a wanted balance between a strong natriuretic effect and weak sodium retaining mechanism not necessarily is achieved by a high dose and that information concerning that problem must be obtained from studies in relevant patient groups.