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At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Risk of tumour growth along thermometry catheter trace: a case report.

A patient with recurrent rectal cancer was treated with the combination of radiotherapy plus hyperthermia. Intratumoral thermometry probes were introduced within closed-tip catheters, inserted through the buttocks under computed tomography (CT) control. Catheters were fixed to the skin to stay in place during the whole treatment series. At the end of the radiotherapy series, tumour progression was apparent. Seven months following treatment, tumour growth was visible at the insertion site of one of the catheters. This finding indicates that catheters should not be placed outside the treatment volume involved in any locally curative treatment.

Adenocarcinoma↗
PubMedDate not supplied

A recommended revision in the RTOG thermometry guidelines for hyperthermia administered by ultrasound.

RTOG thermometry guidelines for clinical trials of hyperthermia using planar ultrasound recommended that temperatures be mapped in polyurethane catheters by use of single-junction copper-constantan thermocouples. These guidelines were based on an assumption that the error in temperature measurement due to thermal conduction would generally not exceed +/- 0.3 degrees C. The validity of this assumption was tested with a commercially available single-junction copper-constantan thermocouple. The width of the point spread function, an indicator of the relative magnitude of the conduction error, was five times greater than expected. As a result, the conduction error is projected to exceed 0.3 degrees C in a temperature gradient of only 1.5 degrees C/cm. This projection was confirmed by mapping a thermal peak which simulates a typical clinical temperature profile. This peak had an amplitude of 6 degrees C, a full-width at half-maximum of 3.5 cm, and a maximum gradient of approximately 3 degrees C/cm. Temperatures measured at 0.5-cm intervals over the span of this peak were in error by a mean of +/- 0.6 degrees C. It is strongly recommended that the RTOG guidelines be revised to replace copper-constantan thermocouples with manganin-constantan single- or multi-junction thermocouples which will assure that the conduction error will be < +/- 0.3 degrees C.

Body Temperature↗
PubMedDate not supplied

Verification of a hyperthermia model method using MR thermometry.

Simulation of hyperthermia induced power and temperature distributions is becoming generally accepted and finding its way into clinical hyperthermia treatments. Such simulations provide a means for understanding the complete three-dimensional temperature distribution. However, the results of the simulation studies should be regarded with caution since modelling errors will result in differences between the actual and simulated temperature distribution. This study uses a diffusion weighted magnetic resonance (MR) based technique to measure hyperthermia induced temperature distributions in a three-dimensional space in a non-perfused phantom. The measured data are used to verify the accuracy of numerical simulations of the same three-dimensional temperature distributions. The simulation algorithm is a finite element based method that first computes the electromagnetic induced power deposition then the temperature distribution. Two non-perfused phantom studies were performed and qualitatively the MR and simulated distributions agreed for steady-state. However, due to the long MR sampling time (approximately 4 min), poor agreement between the simulations and MR measurements were obtained for thermal transients. Good agreement between the simulations and fibreoptic thermometry measurements were obtained. The fiberoptic measurements differed from the simulations by 0.11 +/- 0.59 degrees C and -0.17 +/- 0.29 degrees C (mean +/- standard deviation for the two studies).

Algorithms↗
PubMedDate not supplied

Heating characteristics of a 434 MHz transurethral system for the treatment of BPH and interstitial thermometry.

A system is described for delivering transurethral hyperthermia to the prostate. The system used a helical coil antennae powered by a 434 MHz generator. The antennae was housed in a disposable 22 Ch Foley catheter with water passed down the centre of the winding of the antennae and returned between the antennae and inner wall of the catheter. The flow rate of the circulating water could be varied. The position of the antennae was adjustable with respect to the balloon, essentially altering the length of the antennae. Urethral wall temperature was measured with a thermocouple passed down a small tube moulded into the outer wall of the catheter. Rectal temperature was measured using thermocouples placed in grooves machined into a custom made perspex rectal applicator. A computer program displayed the temperature and controlled the power to the generator. The SAR around the catheter was measured in a polyacrylamide gel phantom. However this does not take into account the effects blood flow and thermal conduction which may have important clinical implications. In order to investigate the actual temperature within the prostate during treatment, a group of patients underwent intraprostatic thermometry.

Acrylic Resins↗
PubMed1987

Finger thermometry in the assessment of subjects with vibration-induced white finger.

The measurement of finger skin temperature (FST) is one of the most commonly used methods for evaluating the response of the digital vessels to cold stimulation. In well-controlled experiments a significant correlation has been observed between FST and digital blood flow over a wide range of water temperatures. On the contrary, FST in air is considered an inadequate index of digital skin circulation since, at a given ambient temperature, FST depends not only on the rate of blood flow through the digit but also on environmental conditions. Despite these limitations, FST recording after a cooling procedure has been used in surveys of vibration-induced white finger (VWF), and a delayed finger rewarming time has been proposed as an indicator of digital vasospasm in workers with VWF. Finger skin thermometry can differentiate between VWF groups and healthy groups, but it is unsuitable for diagnosing Raynaud's phenomenon on an individual basis. The thermometric method has good specificity but its sensitivity is lower than that of plethysmographic techniques. FST after cold provocation may be considered a useful screening test in field studies, while more sensitive methods should be employed to confirm VWF symptoms in individuals objectively, especially for insurance compensation purposes.

Fingers↗
PubMed1998

[Effectiveness of preoperative radio-chemo-thermotherapy with respect to thermometry in locally advanced rectal carcinoma].

Additional hyperthermia is able to intensify the effect of radio-chemotherapy in locally advanced rectal cancer. The datas represents favourable locally effect, if the necessary parameters of thermometry are achieved. We could demonstrate a correlation between temperatures and downstaging of the primary tumor. Consequently, aim of further developments is to optimize hyperthermia technology.

Combined Modality Therapy↗
PubMed2004

[Tympanic thermometry in diagnosis of exudative otitis media in children].

Tympanic and axillary temperatures were measured in 90 children (161 ears) with exudative otitis media (EOM) and 20 otologically healthy children (40 ears). It was discovered that in EOM patients the difference between tympanic and axillary temperatures is greater than in healthy children. This increased difference is caused by the state of the tympanic mucosa. The influence of surgical and conservative treatments on tympanic mucosa temperature and, therefore, on the difference between tympanic and axillary temperatures in these patients are outlined. It is recommended to use tympanic thermometry with consideration of case history data and otoscopic picture as a screening method for diagnosis of EOM in mass prevention examinations of children, in family physician practice and in selection of children for more comprehensive check-up in diagnostic centers as well as for control over treatment results in EOM children.

Adolescent↗
PubMed1991

Infrared ear thermometry.

Many hospitals are considering using infrared (IR) ear thermometers (also called tympanic membrane thermometers) as an alternative to traditional temperature-measurement devices. IR technology allows users to quickly and noninvasively measure body temperature by inserting a directional probe into the ear canal. For infection control, ear thermometers offer the advantages of not contacting mucous membranes and eliminating the need for special handling procedures. For use on unconscious patients or those who are otherwise unwilling or unable to cooperate with traditional techniques, IR ear thermometers offer a more comfortable and less stressful method of temperature taking for both patients and nurses, especially where rectal temperatures are used. The recent entry into this market by major companies and distributors and the release of several new IR ear thermometers have helped to further stimulate interest in this technology. However, a complete transition to IR ear thermometers throughout the hospital may not be necessary and should be made only after these devices have been successfully used in selected clinical locations, such as emergency departments, critical care areas, recovery areas, and labor and delivery rooms. Clinical users must be familiar with the technique needed for temperature measurement with these instruments and understand the differences between temperatures taken in the ear canal and those obtained from traditional sites. In the following article, we first present and overview of clinical thermometry, describing traditional temperature-measurement sites and devices. We then discuss the advantages and disadvantages of using the ear canal, including the tympanic membrane (TM), as a site for temperature measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Calibration↗
PubMed1991

[The method of endobronchial thermometry in the evaluation of the activity of tuberculosis of the respiratory organs].

Local temperature reactions were studied in 72 patients with intrathoracic tuberculosis (64 of them had active tuberculosis and 8 residual pulmonary changes after prior tuberculosis). Endobronchial thermometry in the dynamics of a specific process was conducted in 7 patients with pulmonary tuberculosis. Bronchial temperature was measured during fibrobronchoscopy under local anesthesia by a device of an original design. Marked thermoregulatory disturbances were found in the bronchi which were caused by a specific active process in the lungs and were manifested in a significant decline of endobronchial temperature as compared to normal values. Clinical recovery of pulmonary tuberculosis with the development of posttuberculous fibrous changes does not cause any disturbances in local temperature reactions. The temperature level in the bronchi is significantly affected by the nature and degree of the inflammatory process in the bronchi.

Adult↗
PubMed1991

Endoscopic thermometry in healthy controls and in gastroesophageal malignancy.

A thermocouple passed through the biopsy channel of an upper gastrointestinal fiberscope was used to measure mucosal temperature in health and disease. We documented significant mucosal temperature differences at nine sites in 32 normal controls. Duodenal bulb, stomach and the esophagus were warmer than the sublingual site. Mid-esophagus was warmer than the distal esophagus. Next, patients with 50 histologically benign gastric ulcers (GU) were compared with 18 malignant GU containing adeno-div carcinoma. In benign GU there was a marked temperature gradient between a normal reference site (lesser curvature) and a warmer edge (+0.47 degrees C, p less than 0.01) and the crater (+0.73 degrees C, p less than 0.001) of the ulcer. Malignant GU showed no difference to the reference site. In thirteen patients with esophageal cancer, the tumor and also the adjacent mucosa proximal and distal to the tumor were cooler than the corresponding sites in normal controls. Upper GI malignancy appears to have a cooler mucosa. This pattern differs from normal and from non-malignant inflammation. These results support the need for further evaluation of the diagnostic potential of mucosal thermometry, especially of infrared videoendoscopy. (Fig. 1, Tab. 3, Ref. 10).

Aged↗
PubMed1990

[Heat exchange and skin thermometry before and after lumbar sympathectomy].

The authors studied the flow of heat and skin temperature of the legs and feet in 73 patients with atherosclerosis obliterans before and after lumbar sympathectomy. A regularity was revealed according to which numerical determination of heat emission in combination with thermometry in characteristic points of the leg and foot was a good test in determining the stage of the disease and a prognostic index of the efficacy of lumbar sympathectomy and rehabilitation of the patient in the immediate and late-term postoperative period.

Adult↗
PubMed1986

[Thermometry of hyperthermia].

Invasive thermometers with a thermo-couple or an optical fiber are widely employed in hyperthermia treatment. A non-invasive method is wanted, but we can not present one at present. Several results obtained in Japan on studies of non-invasive thermometry are as follows: Mizushina, after simultaneous measurement of microwave radiation of the three frequencies located between 1 to 4 GHz, determined in real-time temperature dependence on depth to 5 cm beneath the skin of a rabbit, Yamaura, with his 915 MHz-CT apparatus, obtained 0.4 degree C temperature resolution on the phantom made of a hot cylinder in a cool tank both filled with NaCl solution, and Amemiya et al., assuming use of an NMR apparatus, showed theoretically that temperature could be measured after about 1 minute with the error of +/- 0.5 degree C if one measures M0 parameter in focusing magnetic field mode.

Electromagnetic Fields↗
PubMedDate not supplied

[Thermometry in experimental inflammation. I. Studies on the circadian rhythm of the paw temperature in healthy rats and temperature behavior in acute inflammation after injection of kaolin, carrageenin and dextran].

Plantar paw skin temperature development was examined in 26 healthy male albino rats using Heimann's infrared thermometer KT 41. This examination was carried out on two groups of 12 and 14 male rats after intraplantar injection of kaolin, carrageenin, and dextran. Normal untreated animals showed a distinct circadian course of daily temperature, with minimal temperatures in the morning and maximal ones in the evening, and a mean difference of 3.9 degrees C. Among the phlogistic substances injected, kaolin proved to induce the most powerful increase in plantar skin temperature. It was followed by carrageenin; temperature increase in kaolin edema, however, started later than that induced by carrageenin. No pathological skin temperature increase was found after the injection of dextran. Physiological circadian temperature course, however, was modified in an undulating fashion. All phlogistic substances persistently disturbed thermoregulation in the inflamed rat paw. The comparison of temperature development in our experiments with paw swelling in similar models described in the literature did not always show a correspondence. Quantification of the intensity of experimental inflammations in animals using only a single parameter is thus not always adequate; under certain circumstances it can even lead to wrong conclusions. Nevertheless, infrared thermometry proved to be a very suitable method of estimating skin temperature as a parameter of inflammation.

Animals↗
PubMed1984

[Direct thermometry of the pancreas in the postoperative period].

Direct thermometry of the pancreas in 44 patients after operations for carcinoma of the pancreato-duodenal zone or chronic pancreatitis has shown a relationship between temperature of the pancreas stump and the fermentemia degree. Characteristic changes of temperature regimens are observed 5-17 hours earlier than manifestations of clinical symptoms of postoperative pancreatitis make their appearance.

Adult↗
PubMed1982

Error sources affecting thermocouple thermometry in RF electromagnetic fields.

Thermocouple thermometry errors in radiofrequency (typically 13, 56 MHZ) electromagnetic fields such as are encountered in hyperthermia are described. RF currents capacitatively or inductively coupled into the thermocouple-detector circuit produce errors which are a combination of interference, i.e., 'pick-up' error, and genuine rf induced temperature changes at the junction of the thermocouple. The former can be eliminated by adequate filtering and shielding; the latter is due to (a) junction current heating in which the generally unequal resistances of the thermocouple wires cause a net current flow from the higher to the lower resistance wire across the junction, (b) heating in the surrounding resistive material (tissue in hyperthermia), and (c) eddy current heating of the thermocouple wires in the oscillating magnetic field. Low frequency theories are used to estimate these errors under given operating conditions and relevant experiments demonstrating these effects and precautions necessary to minimize the errors are described. It is shown that at 13.56 MHz and voltage levels below 100 V rms these errors do not exceed 0.1 degrees C if the precautions are observed and thermocouples with adequate insulation (e.g., Bailey IT-18) are used. Results of this study are being currently used in our clinical work with good success.

Diathermy↗
PubMedDate not supplied

[The use of dynamic radiant thermometry in assessing the mechanism of action of drugs].

We studied the functional state of the kidneys, dynamic radiation heat losses from the lumbar area in 21 healthy subjects against the 1% water loading background and after the indometacin intake on 3 consecutive days, reckoned on the basis of 1 mg per 1 kg of body weight, at 25 mg 3 times/day. Administration of indometacin, even on short-term basis, was found to be associated with appreciable decrease in renal blood circulation, the result of this event being reduction of glomerular filtration and excretory function of the kidneys, and moderation in renal proteinuria. Dynamic radiation thermometry may be used in the assessment of the drug effect on renal haemodynamics and functional state of the kidneys. In patients with glomerulonephritis indometacin should not be prescribed.

Body Temperature Regulation↗
PubMed1994

Accuracy of infrared ear thermometry and other temperature methods in adults.

OBJECTIVE: To compare the accuracy of infrared ear-based temperature measurement in relation to thermometer, ear position, and other temperature methods, with pulmonary artery temperature as the reference. METHODS: Ear-based temperature measurements were made with four infrared thermometers, three in the core mode and two in the unadjusted mode, each with tug and no-tug techniques. Pulmonary artery, bladder (n = 21), and axillary temperatures were read after each ear-based measurement and oral temperature was measured once when possible (n = 32). Subjects consisted of a convenience sample of 50 patients with pulmonary artery catheters who were in adult critical care units of a university teaching hospital. RESULTS: Ear-based measurements correlated well with pulmonary artery temperature (r = .87 to .91), although closeness of agreement differed among thermometer-mode combinations (mean offsets = -0.7 to 0.5 degree C) and had moderately high variability between subjects (SD = +/- 0.5 degree C) with all instruments. Use of an ear tug either made no difference or resulted in slightly lower readings. Bladder temperature was nearly identical to pulmonary artery temperature values (r = .99, offset = 0.0 +/- 0.2 degree C). Oral readings were slightly lower (r = .78, offset = -0.2 degree C) and axillary readings much more so (r = .80 to .82, offset = -0.7 degree C); both were highly variable (SD = +/- 0.6 degree C) and affected by external factors. CONCLUSIONS: Infrared ear thermometry is useful for clinical temperature measurement as long as moderately high variability between patients is acceptable. Readings differ among thermometers, although several instruments provide values close to pulmonary artery temperature in adults. Readings are not higher with an ear tug. Bladder temperature substitutes well for pulmonary artery temperature, whereas oral and axillary values may be influenced by external factors in the critical care setting.

Adult↗