Calibration of a Microselectron HDR iridium 192 source

A method for the calibration of the output, in terms of an air kerma rate, of the high activity miniature iridium 192 sources used in the Microselectron HDR afterloading unit is described. An air kerma rate is measured using a calibrated thimble chamber in an "in-air" calibration jig. The results are compared with an air kerma rate derived from the manufacturer's test certificate. In some cases, the ionization chamber measurements have been followed by a further calibration check using thermoluminescent dosimetry. Other checks carried out when a new source is received are also briefly described.     

The acoustic fields of the Wolf electrohydraulic lithotripter

Electric sparks are used as the sources for both intra- and extracorporeal shock wave lithotripters. Upon ignition, a pressure pulse, headed by a shock, is generated that propagates as a spherically diverging wave. Simultaneously, a bubble is created that, in the case of the Wolf Model 2137.50 Electrohydraulic Lithotripter, expands to a radius of approximately 5 mm and collapses spontaneously after approximately 1 msec. Upon rebound, the bubble generates a second pressure pulse that is almost equal in amplitude and acoustic energy to the first shock wave. Measured pressures are almost entirely positive and decrease in amplitude with the reciprocal of the distance from the source. For the Wolf lithotripter at its maximum output setting, the pressure amplitude at a distance of 3 cm from the spark is typically 3 MPa.     

Development and validation of a screening instrument for bipolar spectrum disorder: the Mood Disorder Questionnaire

OBJECTIVE: Bipolar spectrum disorders, which include bipolar I, bipolar II, and bipolar disorder not otherwise specified, frequently go unrecognized, undiagnosed, and untreated. This report describes the validation of a new brief self-report screening instrument for bipolar spectrum disorders called the Mood Disorder Questionnaire. METHOD: A total of 198 patients attending five outpatient clinics that primarily treat patients with mood disorders completed the Mood Disorder Questionnaire. A research professional, blind to the Mood Disorder Questionnaire results, conducted a telephone research diagnostic interview by means of the bipolar module of the Structured Clinical Interview for DSM-IV. RESULTS: A Mood Disorder Questionnaire screening score of 7 or more items yielded good sensitivity (0.73) and very good specificity (0.90). CONCLUSIONS: The Mood Disorder Questionnaire is a useful screening instrument for bipolar spectrum disorder in a psychiatric outpatient population.     

Treatment of localized prostate cancer using a combination of high dose rate Iridium‐192 brachytherapy and external beam irradiation: Initial Australian experience

Combination high dose rate brachytherapy (HDRB) and external beam radiation therapy is technically and clinically feasible as definitive treatment for localized prostate cancer. We report the first large Australian experience using this technique of radiation dose escalation in 82 patients with intermediate‐ and high‐risk disease. With a median follow up of 3 years (156 weeks), complications were low and overall prostate‐specific antigen progression‐free survival was 91% using the American Society for Therapeutic Radiology and Oncology consensus definition. The delivery of hypofractionated radiation through the HDRB component shortens overall treatment time and is both biologically and logistically advantageous. As a radiation boost strategy, HDRB is easy to learn and could be introduced into most facilities with brachytherapy capability.     

Screening for complement deficiency in bacterial meningitis

Seventy-seven children with bacterial meningitis were screened for complement deficiency. Both the classical and the alternate pathways were normal in 75 patients. Transiently reduced total haemolytic activity of the classical pathway was documented in a boy with meningococcal meningitis. Total haemolytic activity of both the classical and the alternate pathways were reduced in another patient with pneumococcal meningitis: individual complement components determination indicated predominant activation of the alternate pathway.     

Rising incidence of type 1 diabetes in Scottish children, 1984-93. The Scottish Study Group for the Care of Young Diabetics

OBJECTIVES: To calculate the incidence of type 1 diabetes in Scottish children aged less than 15 years between 1984 and 1993; to examine changes in incidence; and to calculate the prevalence of diabetes at the end of this period. DESIGN: Three data sources were used to construct the Scottish Study Group for the Care of Young Diabetics register: active reporting of all new cases; reports from the Scottish Morbidity Register 1; and local registers. SUBJECTS: All children resident in Scotland diagnosed with primary insulin dependent diabetes mellitus when less than 15 years of age between 1984 and 1993. MAIN OUTCOME MEASURES: Annual incidence and prevalence rate for Scotland; time trend in incidence over the 10 years; differences in incidence between the three different age groups; and completeness of the register. RESULTS: The average annual incidence for Scotland was 23.9/100,000 children. The prevalence rate was 1.5/1000 in 1993. A total of 2326 cases was identified from the three sources. Capture-recapture analysis suggests a case ascertainment of 98.6%. The annual incidence rates increased at a rate of 2% each year (rate ratio = 1.02, 95% confidence interval (CI) 1.01 to 1.03). The incidence was higher in boys than girls (rate ratio = 1.08, 95% CI 1.00 to 1.18), and the incidence rates increased with age: 15.3/100,000/year for age 0-4 years, 24.4/ 100,000/year for age 5-9 years, and 31.9/ 100,000/year for age 10-14 years. CONCLUSIONS: The incidence of type 1 diabetes in Scotland is increasing and the prevalence is relatively high. These findings have important implications for health service resource allocation. The Scottish Study Group for the Care of Young Diabetics' register provides a base for monitoring and research.