Multi-institutional clinical experience with the Calypso System in localization and continuous, real-time monitoring of the prostate gland during external radiotherapy

PURPOSE: To report the clinical experience with an electromagnetic treatment target positioning and continuous monitoring system in patients with localized prostate cancer receiving external beam radiotherapy. METHODS AND MATERIALS: The Calypso System is a target positioning device that continuously monitors the location of three implanted electromagnetic transponders at a rate of 10 Hz. The system was used at five centers to position 41 patients over a full course of therapy. Electromagnetic positioning was compared to setup using skin marks and to stereoscopic X-ray localization of the transponders. Continuous monitoring was performed in 35 patients. RESULTS: The difference between skin mark vs. the Calypso System alignment was found to be >5 mm in vector length in more than 75% of fractions. Comparisons between the Calypso System and X-ray localization showed good agreement. Qualitatively, the continuous motion was unpredictable and varied from persistent drift to transient rapid movements. Displacements > or =3 and > or =5 mm for cumulative durations of at least 30 s were observed during 41% and 15% of sessions. In individual patients, the number of fractions with displacements > or =3 mm ranged from 3% to 87%; whereas the number of fractions with displacements > or =5 mm ranged from 0% to 56%. CONCLUSION: The Calypso System is a clinically efficient and objective localization method for positioning prostate patients undergoing radiotherapy. Initial treatment setup can be performed rapidly, accurately, and objectively before radiation delivery. The extent and frequency of prostate motion during radiotherapy delivery can be easily monitored and used for motion management.     

Twenty-one year tracking of serum non-cholesterol sterols. The Cardiovascular Risk in Young Finns study

Background and aimTo show tracking of cholesterol metabolism, the ratios to cholesterol of e.g. serum cholestenol, desmosterol, and lathosterol, reflecting cholesterol synthesis, and cholestanol, campesterol, avenasterol and sitosterol, reflecting cholesterol absorption, were measured 21 years apart.Methods and resultsIn random population samples initially comprising 12- (n = 162), 15- (n = 158), and 18-year-old (n = 148) males participating in the Cardiovascular Risk in Young Finns Study, serum sterols and squalene were measured with gas–liquid chromatography in 1980 and 2001. Quartiles of cholestanol, indicating low to high cholesterol absorption, were defined from the cholestanol values in 1980.Serum cholesterol increased in the oldest age group only, but synthesis markers (except desmosterol) increased in all age groups after the follow-up (e.g. lathosterol, total population +47.3 ± 2.6% (SE), P < 0.001). Campesterol (+69.0 ± 3.0%, P < 0.001) and sitosterol increased, avenasterol was unchanged, and cholestanol decreased (−6.2 ± 0.7%, P < 0.001), respectively. The 1980 synthesis and absorption markers were interrelated with respective values 21 years later in all age groups and quartiles (e.g. lathosterol, total population 1980 vs. 2001 r = 0.460, cholestanol 1980 vs. 2001 r = 0.593, P < 0.001 for both). Synthesis markers were highest in the first and lowest in the fourth quartile both in 1980 and 2001 (e.g. 2001, desmosterol, quartile 1, 99 ± 9, quartile 4, 83 ± 2 μg/mg of cholesterol, P < 0.05).ConclusionsCholesterol metabolism is significantly tracked in adolescent males over the follow-up of 21 years. Thus, high cholesterol synthesis and low absorption characterize subjects with the lowest cholestanol quartile, while those with the highest quartile have low synthesis and high absorption in both adolescence and later in young adult life.     

West Nile virus: Success of public health response underlines failure of the system

The West Nile virus outbreak in 1999 demonstrated the country's capacity to meet an emerging public health threat. However, while the tracking and monitoring efforts that were put into place by 2000 were impressive, the response to the West Nile virus underscores a fundamental deficiency in the capacity of public health regarding the nation's environmental health efforts. Chronic diseases such as asthma, neurological diseases, and birth defects and their potential links to environmental factors are not being adequately tracked and monitored. New public health infrastructure resources are required.     

Effects of loratadine/montelukast on vigilance and alertness task Performance in a simulated cabin environment

Introduction  Sedating effects of some medications used to treat allergic rhinitis (AR) symptoms can impair an individual’s ability to function optimally. The objective of this study was to characterize the effects of a single dose of loratadine/montelukast (L/M) versus placebo and diphenhydramine on daytime somnolence and psychomotor performance in healthy volunteers. Methods  In this single-center, randomized, double-blind, placebo- and activecontrolled,three-way crossover study, healthy volunteers received single doses of placebo, L/M 10 mg/10 mg, and diphenhydramine 50 mg. Subjects (n=23) were evaluated under simulated cabin pressure using the following tools: Vigilance and Tracking Task (VigTrack), measuring vigilance and tracking performance; the Multi-Attribute Task Battery (MAT), measuring ability to perform multiple tasks simultaneously; and the Stanford Sleepiness Scale (SSS), measuring sedative effects of medication, at baseline and each hour from 1 to 6 hours postdose. Safety was monitored via adverse events and vital signs. Results  Performances on VigTrack and MAT from 1 to 6 hours after dosing were not significantly different between L/M and placebo groups; in contrast, diphenhydramine resulted in significant impairment of tracking for up to 5 hours (P≤0.01) and vigilance performance for up to 3 hours (P≤0.05) on VigTrack versus placebo. Scores of subjective sleepiness as measured by SSS were similar for patients treated with L/M versus placebo, whereas significant increases in sleepiness occurred between 1–5 hours posttreatment in diphenhydraminetreated patients versus placebo-treated patients (P≤0.05). Conclusions  L/M is similar to placebo in effects on daytime somnolence and psychomotor performance. L/M treatment resulted in significantly less sleepiness and impairment of vigilance and tracking than diphenhydramine.     

Transcallosal White Matter Degradation Detected With Quantitative Fiber Tracking in Alcoholic Men and Women: Selective Relations to Dissociable Functions

Introduction: Excessive alcohol consumption can adversely affect white matter fibers and disrupt transmission of neuronal signals. Here, we examined six anatomically defined transcallosal white matter fiber bundles and asked whether any bundle was specifically vulnerable to alcohol, what aspect of white matter integrity was most affected, whether women were more vulnerable than men, and whether evidence of compromise in specific bundles was associated with deficits in balance, sustained attention, associative learning, and psychomotor function, commonly affected in alcoholics. Methods: Diffusion tensor imaging quantitative fiber tracking assessed integrity of six transcallosal white matter bundles in 87 alcoholics (59 men, 28 women) and 88 healthy controls (42 men, 46 women). Measures included orientational diffusion coherence (fractional anisotropy, FA) and magnitude of diffusion, quantified separately for axial (longitudinal; λL) and radial (transverse; λT) diffusivity. The Digit Symbol Test and a test of ataxia were also administered. Results: Alcoholism negatively affected callosal FA and λT of all but the sensory‐motor bundle. Women showed no evidence for greater vulnerability to alcohol than men. Multiple regression analyses confirmed a double dissociation: higher diffusivity in sensory‐motor and parietal bundles was associated with poorer balance but not psychomotor speed, whereas higher diffusivity in prefrontal and temporal bundles was associated with slower psychomotor speed but not balance. Conclusions: This study revealed stronger alcohol effects for FA and radial diffusivity than axial diffusivity, suggesting myelin degradation, but no evidence for greater vulnerability to alcohol in women than men. The presence of brain‐behavior relationships provides support for the role of alcoholism‐related commissural white matter degradation as a substrate of cognitive and motor impairment. Identification of a double dissociation provides further support for the role of selective white matter integrity in specific domains of performance.     

Quantification of respiration-induced abdominal tumor motion and its impact on IMRT dose distributions

PURPOSE: The treatment of moving targets with intensity-modulated radiotherapy may introduce errors in dose delivery. The motion of tumors in the abdomen was studied using quantitative fluoroscopic analysis, and the effect on dose delivery to the target was studied. METHODS AND MATERIALS: Fluoroscopy sessions for 7 patients with pancreas or liver tumors and fiducial clips were recorded, converted to digital format, and analyzed to quantify the characteristics of tumor motion. Intensity-modulated radiotherapy plans were generated for 3 patients (a total of five plans), and the dose-volume histograms for the target volume were compared between plans with and without tumor motion. RESULTS: The average magnitude of the peak-to-peak motion for the 7 patients in the craniocaudal and AP directions was 7.4 mm and 3.8 mm, respectively. The clip motion varied widely, because the maximal clip excursions were about 47% greater than the average clip excursions for each patient. The inclusion of tumor motion did not lead to a significant degradation in the target dose-volume histogram for four of five treatment plans studied. CONCLUSION: The amount of tumor motion for most patients in this study was not large but could, in some instances, significantly degrade the planned target dose-volume histogram. For some patients, therefore, motion mitigation or intervention during treatment may be necessary.     

The relationship between changing body height and growth related changes in maximal aerobic power

Summary In order to analyse the relationship between maximal aerobic power and height, body mass and lean body mass a multi-longitudinal survey was conducted on three different age groups of randomly selected children from a small Czech community. Beginning at the initial ages of 8, 12 and 16 years subjects were subsequently retested three times at 2-year intervals. At overlapping ages there were no differences in the various age groups between height and . By utilizing mean values for the various parameters at specific calendar ages a growth curve was constructed for each sex for the age range 8–20 years. The values were compared with longitudinal studies in various countries and no substantial differences were found. When was then compared to height, body mass and lean body mass it was apparent that the almost linear relationship with height was the most precise. In addition the children remained, generally speaking, in their same rank order for for the three different age groupings.     

Equipment for the quantification of motor performance for clinical purposes

An apparatus is described for the quantitative assessment of important parameters that characterise motor performance in normal subjects and in patients with different types of motor disorders. The apparatus has a handle that can be moved along a straight horizontal track either by the subject (to study voluntary movements) or by a torque motor (to study reflex activity). During voluntary movements the mass and friction of the mechanical part of the equipment are eliminated by feedback of the force exerted at the handle by the subject. The computer program that controls the apparatus gives a choice of four different tests that characterise different aspects of the motor system: the reflex organisation, the regulation of viscoelastic properties mediated in part by reflex activity, the control of fast goal-directed movements, and the performance in a tracking task. The results of a pilot study to the tracking behaviour of clumsy children show that the group of clumsy children differs from a group of normal children in the latency of the tracking response, in the ability to track high-frequency components and in the fact that clumsy children introduce relatively more frequency components in the response that are not present in the tracking signal.     

Foveal tracking cells in the superior temporal sulcus of the macaque monkey

Summary Visual responses were recorded from neurons in the superior temporal sulcus (STS) of awake, behaving cynomolgus monkeys trained to fixate a small spot of light. Visual receptive fields, directionality, and responses during visual tracking were examined quantitatively for 50 cells in the foveal portion of the middle temporal (MT) visual area and surrounding cortex. Directionality indices and preferred directions for tracked and nontracked stimuli were compared. Eighteen cells (18/50 = 36%) were found to respond preferentially during tracking (tracking cells), 7 within MT, 9 in area FST on the floor of the STS, and 2 in unidentified areas. Three distinctly different tracking response profiles (VTS, VTO, and T) were observed. VTS and VTO cells had foveal receptive fields and gave directionally selective visual responses. VTS cells (3 in foveal MT, 6 in FST, 1 in an unidentified area) had a preferred visual direction that coincided with the preferred tracking direction, and began responding 50–100 ms before the onset of tracking. VTO cells (4 in foveal MT, 0 in FST, 1 in an unidentified area) had a preferred visual direction opposite to the preferred tracking direction, and began responding 0–100 ms after the onset of tracking. T cells (0 in MT, 3 in FST) had no visual responses and began responding simultaneously with the onset of tracking. It is suggested that this region of the brain could be the primary location for converting direction-specific visual responses into signals specifying at least the direction of an intended pursuit movement.