[Safety and electromagnetic compatibility in sanitary field]. / Sicurezza e compatibilità elettromagnetica in ambito ospedaliero.

In sanitary field and especially in a hospital, multiple sources of non ionizing radiation are used for diagnostic and therapeutic aims. In sanitary sector both workers and users are present at the same time, and in some cases general population could need higher protection than workers in relationship to the exposition to electromagnetic fields. In order to protect health and safety of patients, general population and workers of hospitals and with the aim to identify, analyze, evaluate and study its level of significance, electrical, magnetic and electromagnetic sources Research Italian project Si.C.E.O. (Safety And Electromagnetic Compatibility In Sanitary Field) was instituted. Target of our research project was to deepen risk of exposition elements with analysis of outdoor (e.g. power lines, transmission cabinets) and indoor (e.g. equipment for physical therapy) sources, located in sanitary structures and to verify the level exposition of workers and common population end the respect of specific regulation, and finally to define technical and organizational measures really useful for protection and reduction of risk.

A comparison of accuracy of computer treatment planning systems in brachytherapy.

An intercomparison was made between dose-rate point calculations with five commercial computer treatment planning systems used in brachytherapy. Sixteen Italian radiotherapy medical physics institutions performed a twofold test, respectively for point and linear sources, reproducing actual clinical implants and the results were compared to references values. The test was designed in order to determine the errors introduced separately by computation and by implant reconstruction via orthogonal films. The results show that for point sources a better accuracy can be achieved than for linear sources. It is also shown that a large variation of results exists between computation systems and the variability is larger for linear sources. The digitizing procedure adds a large amount of error. In the whole set of calculation points, the overall percent difference between computed and reference dose-rate values is larger than +/- 5% in 18% cases for point and in 52% cases for linear sources, with data input by digitizer. It seems that relevant errors do occur when computing actual dose rates, resulting in clinically relevant inaccuracies in the calculated absorbed dose and in its relative effectiveness.

Muscular pain caused by isometric contraction: evaluation of pain through visual analog scale.

Pain caused by muscular isometric contraction was investigated through use of the visual analog scale. The results demonstrate that the latency time and the time to reach maximum intensity are inversely proportional to the amount of the load; therefore increase of pain is linear. The high statistical significance of the results suggests that pain by isometric contraction could be a comparison test for somatic pain evaluation in spontaneous pathological conditions.

Effects of aerobic exercise on muscular pain sensitivity.

Muscular pain sensitivity after aerobic exercise was investigated in ten healthy men aged 20 to 30 years in four tests at five-day intervals to determine if previous aerobic work leads to a hyperalgesic status. The intensity of pain was recorded, by visual analog scale, every 30 seconds after the injection of 1 ml of 10% and of 20% sodium chloride hypertonic solution, both during basal conditions, and 1 ml of 10% sodium chloride hypertonic solution 1 and 60 minutes after 30 minutes of submaximal rectangular exercise. The injection of 10% sodium chloride solution 60 seconds after exercise gave rise to a clear increase in pain, similar to that induced by the 20% sodium chloride solution given during basal condition. This observation shows that submaximal exercise produces a hyperalgesic state in the active muscle. This hyperalgesia probably explains the clinical manifestation of latent algogenic triggers during physical activity.

An electrical model of biological tissues undergoing hyperaemia.

Tissue hyperaemia is a physiological consequence of the temperature increase that follows, for example, the absorption of electromagnetic or ultrasound power in clinical diathermy. Diathermy, as well as other physical therapies (for example massotherapy), affects the local blood content of tissues through various mechanisms (vasoconstriction/dilatation, opening/closing of precapillary sphincters). A method for evaluating hyperaemia in superficial and medium-depth tissues has been recently proposed, which is based on four-electrode impedance measurements. A microcirculation model has also been developed to describe the hyperaemic effects of local diathermic therapy. This paper describes an electrical model of the tissues in hyperaemic conditions which allows us to correlate electrical impedance measurements to microcirculation modifications.

Hyperaemia evaluation in clinical diathermy by four-electrode impedance measurements.

The four-electrode electrical impedance measurement technique is proposed for the evaluation of the hyperaemia variation in tissues treated by diathermic therapy. An impedance meter suitable for such measurements is described, and an electrical model of the heated tissues, concerning the impedance variation during diathermy and its relation with hyperaemia, is presented. The occurrence of the substantial contribution of blood to the overall transverse impedance is demonstrated by comparing the experimental results with those arising from a 2D electrical/thermal model of the treated tissues. A two-admittance model is proposed to explain the electrical behaviour of the tissues treated by diathermy. The model allows us to separate the impedance violation due to the temperature dependence of tissue conductivity from that due to the change of tissue blood content. The results of preliminary measurements of tissue impedance on healthy volunteers treated by electromagnetic diathermy are presented and discussed, showing the feasibility of impedance detection of hyperaemia variations inside tissues.

Radiotherapy of oral tongue cancer.

The results in the treatment of oral tongue cancer are analysed to suggest a highly specified therapeutic program. Two hundred and thirty-two cases, radiologically treated at the Istituto del Radio Alberti, Brescia, Italy, from 1964 to 1978 are considered. Depending on the staging, exclusive interstitial curietherapy, exclusive external radiotherapy, or external plus interstitial therapy were applied. The therapy of locoregional lymph nodes was surgical and/or radiological. The statistical analysis deals with actuarial survival, local remission, recurrences and radionecroses. Particular attention is paid to N0 cases that became N positive. The suggested therapeutic program depends strictly on the staging and defines also the optimal doses.

Multifactorial analysis of NOC lung carcinoma radiotherapy.

In order to evaluate survival of non-oat-cell lung carcinoma patients treated exclusively with radiotherapy, the authors analyzed a series of 791 cases irradiated at the Istituto del Radio "O. Alberti" from 1978 to 1982. The authors selected a homogeneous group of 131 patients, treated with high energy photons and with a fractionation course of a dose ranging from 1.75 to 2.00 Gy per fraction, 5 fractions per week, total dose ranging from 40 to 65 Gy within 4 to 8 weeks and with a time dose factor (TDF) ranging from 60 to 108. The survival curve was computed according to several prognostic factors by means of the Kaplan and Meier approach; a multifactorial analysis was carried out according to Cox's model. No factor significantly affected survival at the level P less than 0.05, except complications: anyway, TDF and tumor size seem to play a particular role. The non-oat-cell lung carcinoma patient who can profit from radiotherapy may be only partially featured: an improved survival and quality of life may be achieved if there are correct criteria to include the patient in the radiotherapy program, if the tumor is small, heavy complications are absent and treatment TDF ranges from 82 to 92.

High-dose interstitial brachytherapy for glioblastoma multiforme.

AIMS AND BACKGROUND: The long-term prognosis for survival of patients with inoperable glioblastoma multiforme (GBL) is very poor. Conventional external radiotherapy gives only transitory result. This severe prognosis led us to elaborate a high-dose rate (HDR), after-remote-loading brachytherapy treatment protocol: our aim was both therapeutic and psychologic. METHODS: Five patients with GBL (T1 G4 UICC) were treated with stereotactic biopsy followed by HDR brachytherapy. A unique coaxial after-loading catheter was stereotactically inserted through the center of the target volume. The treatment schedule considered 5 fractions, 5 Gy/fraction at the dose specification surface, 2 fractions per day. RESULTS: The treatment was well tolerated. Tumor progression started again at the 8th to the 16th week from the end of the treatment. ECOG performance status at the 8th week was better than before the therapy in 2 of 5 patients and was stable in 2 of 5 patients. Order neuroperformance status was stable in 2 patients at 8 weeks. At the 16th week there was neurologic deterioration. The average survival was 21 weeks. CONCLUSIONS: Our approach seems to be of some interest for the palliation of GBL, and it offers some advantages, in particular regarding the short treatment period. Our procedure can be improved: a multi-catheter implant and a more fractionated schedule could be taken into account.

High-dose-rate brachytherapy for poor-prognosis, high-grade glioma: (phase II) preliminary results.

AIMS AND BACKGROUND: The purpose of this study was to investigate the palliative effectiveness of an interstitial fractionated high-dose-rate (HDR) brachytherapy regimen in patients with poor-prognosis, high-grade glioma. METHODS: An after-remote-loading microSelectron HDR lr-192 370 GBq unit was used. A unique coaxial after-loading catheter was stereotactically inserted through the center of the target volume. The treatment schedule was: 5 fractions, 5 Gy per fraction, or alternatively 7 fractions, 3.85 Gy per fraction, at the dose specification surface, 2 fractions per day. Twenty-four patients have been treated: in 17 of them (T1 G3-4) the catheter was implanted during stereotactic biopsy procedure; in the other 7 cases (T2 G3-4), subjected to partial resection and reduced to yT1, the catheter was implanted following surgery with a mean delay of 15 days. RESULTS: The treatment was feasible and well tolerated. The complete course takes no more than 7 days. The acute complication rate (2/24) seems to be acceptable. The median survival was 8 months. No less than 45% of the patients had a WHO grade 2 score or better at any time of follow-up. At 4 months of follow-up, functional status, assessed using a verbally administered Barthel index, had improved from the pretreatment level in 29.1% of the 18 surviving patients and remained stable in another 22.2%. A minimal response or stable disease, according to CT scan, was obtained in about half of the assessable survivors at any time of follow-up. CONCLUSIONS: The short course of brachytherapy provides a good palliation in terms of functional improvement in a high proportion of patients, with low and acceptable toxicity.

[Oxygen therapy with an oxygen concentrator]. / Ossigenoterapia mediante concentratore di ossigeno.

An account is given of the employment of an O2 concentrator (De VO2 955) in chronic bronchopneumopaths with respiratory insufficiency and pulmonary hypertension. An assessment was made of the gas supply modalities, particularly with Venturi masks. In patients with normal or low ventilation, 24% and 28% FiO2 masks gave suitable results, whereas those with a higher concentration were unusable, since the present FiO2 value was not reached. This was probably due to the fact that there is a fall in O2 concentration at high low flow rates, and as a result of an insufficient Venturi effect.

Optimisation of an MDCT abdominal protocol: Image quality assessment of standard vs. iterative reconstructions.

This work aims to construct a method to objectively evaluate CT image quality when new clinical protocol performances must be compared with a standard reference. We compare iterative reconstruction in the image space with filtered back projection reconstruction and accurately quantify the dose reduction. The comparison strategy accounts for both physical and clinical image qualities that are evaluated using a standard metric. The quasi-ideal observer metric is also explored to verify its reportedly high correlation with perceived image quality. Water or spatial resolution phantom images are used to characterise the physical image quality using the classic metrics in the Fourier domain by calculating the modulation transfer functions and noise power spectra (NPS). The clinical-image quality is evaluated with a 4-alternative forced-choice test. The human observers are asked to detect a positive image that contains a simulated lesion in a background image. Then, the same positive images are characterised with the quasi-ideal observer metric, which calculates the non-prewhitening matched filter signal-to-noise ratio (SNRNPWMF). Iterative reconstruction strongly reduces the image noise, but the NPS are slightly shifted to lower frequencies, which gives the images a coarse graininess. Compared with the reference FBP protocol for abdomen exams, the highest dose reduction is 40% if the standard metric is used and 30% if the SNRNPWMF metric is used. The detectability test results achieve a better correlation with SNRNPWMF than with the standard metric. The identified Fourier metric is a useful descriptor of human quality perception and can be used for future protocol optimisation.

Ventilatory response during incremental exercise tests in weight lifters and endurance cyclists.

The effect of a progressively increasing work rate (15 W X min-1) up to exhaustion on the time course of O2 uptake (VO2), ventilation (VE) and heart rate (HR) has been studied in weight lifters (WL) in comparison to endurance cyclists (Cycl) and sedentary controls (Sed). VO2 and VE were measured as average value of 30-s intervals by a semiautomatic open circuit method. VO2max was 2.55 +/- 0.33; 4.29 +/- 0.53 and 2.86 +/- 0.19 l X min-1 in WL, Cycl and Sed respectively. With time and work rate, while VO2 and HR increased linearly, VE changed its slope at two levels. The 1st VE change occurred at a work load corresponding to a mean (+/- SD) VO2 of 1.50 +/- 0.26; 1.93 +/- 0.34; and 1.23 +/- 0.14 l X min-1 in WL, Cycl, and Sed respectively. VO2 values corresponding to the second VE change of slope were 2.18 +/- 0.32 in WL; 3.48 +/- 0.53 in Cycl and 2.17 +/- 0.28 l X min-1 in Sed. The first change of slope might be the consequence of the different readjustment of VO2 on-response and hence of early lactate in the different subjects. The second change seems to be comparable to the conventional anaerobic threshold and is achieved in all subjects when VE vs time slope is 7-10 l X min-1/min of exercise.

[Clinical dosimetry in radium 226 and iridium 192 interstitial therapy of oral tongue cancer (author's transl)]. / Considerazioni clinico-dosimetriche nella curieterapia interstiziale con radio 226 e iridio 192 dei carcinomi della parte mobile della lingua.

On 96 patients with carcinoma of the floating part of the tongue in the early stage treated by interstitial curietherapy alone have been effect both a comparison between the obtainable results with the 192Ir and with the 226Ra and a total valuation of some able factors (dose-rate, total dose, tumor volume) to influence the curietherapy after loading with 192Ir.

[Creation and management of a data bank in oncologic radiotherapy]. / Creazione e gestione di una banca dati in radioterapia oncologica.

Clinical, scientific and technological development has greatly widened the scope and range of oncological radiotherapy. As for database management, favorable conditions come from new available hardware and software facilities and from well-consolidated and universally accepted classifications. The authors' aim was to create and to verify an original database management system for oncological radiotherapy, proved with internationally accepted classifications and directly interfaced to a new package for clinical and epidemiological statistics. An ordinary personal computer was used and a 802-subject statistics was analyzed relative to 1987-1988 series from the Istituto del Radio "O. Alberti", General Hospital and University - Radiotherapy Department, Brescia, Italy. The system seems to be suitable for routine use as well as for research, with good potentials for multicentric use.

Heart rate overshoot at the beginning of muscle exercise.

A characteristic notch in the heart rate (fc) on-response at the beginning of square-wave exercise is described in 7 very fit marathon runners and 12 sedentary young men, during cycle tests at 30% and 60% of maximal oxygen consumption (VO2max). The fc notch revealed a fc overshoot with respect to the fc values predicted from exponential beat-by-beat fitted models. While at 30% of VO2max all subjects showed a fc overshoot, at 60% of VO2max it occurred in the marathon runners but not in the sedentary subjects. The mean time of occurrence of the fc overshoot from the onset of the exercise was 16.7 (SD 4.7) s and 12.2 (SD 3.2) s at 30% of VO2max in the runners and the sedentary subjects respectively, and 23.8 (SD 8.8) s at 60% of VO2max in the runners. The amplitude of the overshoot, with respect to rest, was 41 (SD 12) beats.min-1 and 31 (SD 4) beats.min-1 at 30% of VO2max in the runners and the sedentary subjects respectively, and 46 (SD 19) beats.min-1 at 60% of VO2max in the runners. The existence and the amplitude of the fc overshoot may have been related to central command and muscle heart reflex mechanisms and thus may have been indicators of changes in the balance between sympathetic and parasympathetic activity occurring in fit and unfit subjects.

Statistical evaluation of a total dose-dose rate relationship in oral tongue cancer 192 Ir implants.

A statistical tool has been made by us on 55 patients treated for oral tongue cancer with unique 192 Ir interstitial curietherapy in Brescia from 1973 to 1981. Our aim was to verify a simple analytical relationship proposed and adopted by us for oral tongue cancer implants in order to reduce the total dose with increasing dose rates and to calculate the equivalent total dose when referred to 0.357 Gy/hr. Recurrences and radionecroses are studied in a variance analysis, distinguishing according to stage and total dose; within the dose rate range used, a highly significant difference in radionecrosis rate (P less than 0.005) confirms our isoeffect relationship.