[en] Measurements in the real environment, i.e. with several different electromagnetic field sources and scattering problems, require an accurate analysis of problems concerning narrowband measurements. The aim of the present work was the development of an automatic procedure for narrowband electric field measurements in open sites with multiple sources, in order to perform accurate and reproducible measurements. Results regarding measurements carried out in a suburban site are reported. (author)

[en] From 1976 to 1982, 78 patients with nasopharyngeal cancer (NPC) were treated with definitive megavoltage irradiation in accordance with a uniform protocol. The results of treatment were analyzed and prognostic factors reviewed. The incidence of primary failures was directly related to the extent of nasopharyngeal disease. Similarly, failure in the neck correlated with the N stage, being negligible for N₀ and N₁, while 35.7% for N₃. The presence of bulky cervical nodes was associated with a higher risk for metastases. The histology pattern seemed to significantly affect the ultimate outcome of patients with NPC, since disease-free survival was 65.5% in patients with a diagnosis of undifferentiated carcinoma (UC) and 23.8% in patients with squamous cell carcinoma (SC). The major cause of poor survival in this latter patient group was not only a higher recurrence rate of both primary and nodal disease but a greater incidence of distant metastases as well. (Auth.)

[en] The readjusting between the PET and the scanning can decrease significantly the variations in the delineation of the volumes because the PET introduces a metabolic additional information which allows an improvement of the definition of the margins between the tumoral tissue and the atelectasy. Our study confirms that the use of the PET by readjusting on the scanning for bronchial cancers presents an impact mattering during the planning of the radiotherapy but also for the chosen therapeutic strategy

[en] The I.M.C.R.T. (intensity modulated conformal radiotherapy) allows a better adaptation of the radiation dose distribution at the exact shape of the tumor volume, while respecting the constraints of critical organs protection, but it needs a correct definition of the gross tumor volume. This study confirms that the images merging has an important role for the radiotherapy planning of head and neck tumors. (N.C.)

[en] The brachytherapy by permanent iodine 125 implants is in the localised prostate cancer a clinical treatment well tolerated and characterized by a limited toxicity: the urinary flow before implantation is an important factor of evolution prediction of the acute urinary toxicity, especially with regard to acute urinary retention. The important number of gains implanted near urethra is responsible of the acute urinary toxicity. All patients were in a state of complete remission with a decrease in the concentration of serum P.S.A. to eight months. (N.C.)

[en] From 1979 to 1986, 182 patients with biopsy proven diagnosis of Ewing's sarcoma of bone were observed. One hundred of the 182 patients (72 males, 28 females, median age 15.8 years) with localized disease and no previous treatment were treated with chemotherapy (VCR, ADM, CTX, D-ACT) for 15-18 months. Local treatment was radiotherapy (42 patients), surgery (31 patients), or a combination of both (27 pts). Radiation doses ranged from 45 to 64 Gy given with conventional fractionation. Median follow-up was 51.2 months (24-106). Overall and disease-free survival were, respectively, 58.7 and 42.6%. Resected patients tended to have a better local control (Surgery 93.6%, Surgery + Radiation therapy 92.6%, Radiation therapy 69.1%). Disease-free survival was significantly related to the volume of the primary tumor (bulky: 33.2%, not-bulky: 57.7%), to site (extremities 54.6%, central sites 16.6%, other sites 40.9%), and to local treatment (Radiation therapy 30.3%, Surgery + Radiation therapy 47.9%, Surgery 59.1%). These results are, however, biased because resected patients tended to have smaller tumors in favorable sites

[en] Ultrasonic waves are useful tools to characterize the contact forces between components in non-destructive and non-invasive manners. It has been shown that the transmission and reflection coefficients of the ultrasonic wave are sensitive to the contact pressure or other contact parameters. Theoretically, the normal and tangential stiffnesses of the contact interface govern the transmission/reflection coefficients and can be used as parameters to characterize the contact condition. However, weak and incomplete interfaces, formed by rough surfaces in partial contact, show a highly nonlinear behaviour also when they are excited under free vibrations. In particular, the amplitude of the second harmonic is a relevant index of the contact stiffness, and the nonlinear response is strongly influenced by the nominal contact pressure applied to the boundaries. In this study a new theoretical model of the nonlinear interface stiffness was developed where the stiffness of the contact interface was described as a function of the nominal contact pressure. The developed theoretical contact pressure function of the second harmonic generation at the contact interface was found to agree with good accuracy with the experimental data. Moreover, this paper presents also a theoretical and experimental study aimed at developing an integrity index capable of assessing the stiffness of the contact interface between structures when excited by free vibration or under controlled vibration excitation

No abstract available

[en] From January 1979 to December 1987, 99 patients with a diagnosis of localized soft-tissue sarcoma of the extremities received preoperative radiation therapy (50 patients) or postoperative irradiation (49 cases). In the preoperative RT group, doses ranged from 42 Gy/14 fractions to 51 Gy/17 fractions; the patients treated with postoperative radiation therapy received 46 Gy/23 fractions. The surgical procedure was in each patient complete resection of the mass with preservation of the affected limb. The main cause of failure were distant metastases (33.3%). The incidence of local recurrences was low (7.1%). Recurrences were related to tumor size [<5 cm:0/12; 5-10 cm:2/45 (2.3%); >10 cm:5/42 (11.9%)]. The incidence of distant metastases was higher in the group treated with preoperative radiation therapy (44% vs 22.4%), probably because a high percentage of patients in this group had large tumors. Late complications were analyzed in 59 patients with a follow-up longer than 24 months. Severe complications rate was low (6/59 cases, 10.1%), and higher in the preoperative than in the postoperative RT group (15.4% vs 6.1%), which is probably related to the different fractionations administered

[en] Therapeutic progress has mech improved the prognosis of Hodgkin's disease; therefore longterm complications of the treatment have become a major problem. Among these, the authors focused on osteonecrosis of the femoral head, and conducted a retrospective study on 182 patients treated with inverted-Y-field radiation therapy combined to MOPP chemotherapy in 129 cases. Femoral osteonecrosis was found in 6 patients (3.3%), 5 males and 1 female; 4 of them received combined modality treatment (inverted-Y radiation therapy + MOPP), and 2 radiation therapy alone. The interval between the end of treatment and the radiological finding of femoral osteonecrosis ranged from 23 to 54 months, with a mean of 35 months. On the whole, 10 cases of osteonecrosis of the femoral head (4 bilateral, and 2 unilateral) were observed, and 4 fractures involving the anatomic neck. According to our results, neither a safety dose-limit nor an optimal schedule of combination therapy could be fixed. Besides radiological features and the problems of differential diagnosis, the authors considered the pathogenesis of femoral head osteonecrosis in the patients with Hodgkin's disease treated with radiotherapy alone or combined to chemotherapy, and suggested the existence of a personal proneness to the lesion and the role of ionizing radiations, corticosteroids and cytotoxic agents, as inducing factors. Because of the different and unexpectable reaction of each patient to the treatment, osteonecrosis preventions is very difficult: however, its complication may be reduced - or even avoided -by subjecting the treated patients to periodic clinical and radiological examinations