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R Ragona

Publications and source records attributed to R Ragona.

At least 55 records · Page 3Linked to original sources
PubMed1989

Three new applicators for hyperthermia.

A computerized system with automatic treatment parameters control for radiological hyperthermia, called Sapic SV03, is presented. The system has been planned and built by the "Sezione Avionica ed Equipaggiamenti" of the Aeritalia in cooperation with the Radiotherapy Department of the University of Turin. The device is supplied with a multifrequency generator system (915, 433, 2-30 MHz) connected with many kinds of applicators, with a fiber optic system for temperature control and a previsional thermometry system. In this paper the authors presented three new applicators. The first one is a concave parallel microstrip applicator at 433 MHz, with a size 16 x 9 cm; the heating pattern is homogenous until 4 cm of depth. This antenna can be used for the treatment of chest wall recurrences of breast cancer. The second is a 27 MHz inductive ring and the third applicator is a pyramidal antenna ("TEM line") that operates at a frequency around 27 MHz.

Computer Systems↗
PubMed1988

Lateral high abdominal ovariopexy: an original surgical technique for protection of the ovaries during curative radiotherapy for Hodgkin's disease.

An original surgical method for gonadal protection in young women given pelvic radiation for Hodgkin's disease is presented. Lateral high ovarian transposition (LHAO) consists of the transposition of the ovaries into the paracolic gutter during staging laparotomy, after disconnecting the gonads from the fallopian tubes by dividing the tubo-ovarian vessels. The technique's effectiveness was assessed by a study using clinical investigation, radioimmunoassay (RIA) determination of sex hormones, and dosimetry; of 18 patients treated, 10 participated in the study. All but one have normal menses and hormone values, and one pregnancy occurred. We also calculated the doses absorbed by the ovaries and proved that, during inverted Y irradiation following LHAO, the ovaries are exposed to nearly one-half the dose they receive after traditional medial transposition. During subtotal nodal irradiation after LHAO, the irradiation dose is higher than after medialisation, but absolute values are minimal and castration is not induced.

Adolescent↗
PubMed1988

[Radiotherapy in the treatment of carcinoma of the major salivary glands].

The authors conducted a retrospective study on 99 patients with malignant tumors of the major salivary glands, who had been treated by radiotherapy between 1976 and 1986: 86 cases of parotid tumors and 13 cases of submandibular gland tumors. Only 28 tumors (28%) were T1-T2, N0-N1. Local control, 3-5 and 8-year survival rates, and complications were considered. Radiation therapy alone was performed on 19 patients (19%), while combined surgical and radiation therapy was performed on 80 patients (80%). The results of radiation therapy alone and combined with surgery are discussed. Loco-regional disease control was obtained in 9 out of 19 patients (47%) by irradiation alone, and by combined irradiation and surgery in 60 out of 80 cases (75%). Distant metastases developed in 23 out of 99 patients (23%). Loco-regional metastases were the most frequent cause of death (20 out of 55 cases: 36%). Severe complications were extremely rare. The results demonstrate not only the advantages of combined treatment but also the value of radiotherapy alone in the treatment of tumors of the major salivary glands.

Adolescent↗
PubMed1987

[Technic and dosimetry in total body irradiation with 18 MeV photons].

Total body irradiation (TBI) is used in our Institution in the conditioning regimen for bone marrow transplantation. The fractionation pattern consists of two daily fractions of 1.65 Gy repeated for 4 days (total dose 13.20 Gy in 8 fractions). Lung dose is reduced by means of lead custom shaped shields directly strapped to the patient surface. TBI is delivered by a THERAC 20 linear accelerator with two opposing AP-PA photon beams with a maximum energy of 18 MeV. Treatment distance is 340 cm and the patient is treated in a semi-standing position. Dosimetry studies in a homogeneous phantom were performed in the treatment geometry and consisted in the determination of: tissue maximum ratios (TMR) at different depths, absorbed dose along the median axis and the diagonal of the field, variation of the absorbed dose in the prescription point with different volumes of scattering material, and transmission of shielding and compensating material. A semi-empiric formula for the calculation of absorbed dose in a point has been obtained. A subsequent study in a Rando phantom with termoluminescent dosimeters (TLD) has shown a +/- 5% agreement between calculated and measured values and a +/- 7% homogeneity.

Humans↗
PubMed1987

[Total cutaneous irradiation with low energy electrons and mycosis fungoides. Technic and dosimetry].

Mycosis fungoides initially involves the epidermis and the superficial layers of derma at a depth of about 1 cm. Wide field irradiation with low energy electrons is therefore the treatment of choice in the initial stages of the disease. In our Institute, total skin electron beam irradiation is delivered with Therac 20 linear accelerator: the lowest available energy is 6 MeV. A lucite sheet of 0.6 cm thickness is used to decrease the energy of the beam. We used film dosimetry to evaluate the homogeneity of dose distribution in an Alderson-Rando phantom with different arrangements of the fields and the lucite sheet: 4 and 6 fields techniques have been compared with different positions of the lucite filter, near the phantom and near the collimator. Six fields yield a better dose distribution: homogeneity is within +/- 3.7%, while with four fields it is within +/- 6%. X-rays contamination is less than 2%. "In vivo" dosimetry has been performed using thermoluminescent dosimeters: homogeneity is within +/- 15%.

Electrons↗
PubMed1987

[Results of radiotherapy in the treatment of 218 carcinomas of the tonsillar area].

After a brief review of the literature, the results of the treatment by radiation therapy in 218 patients with tonsillar region carcinoma are reported. The patients were treated at the Turin University Radiotherapy Department (131 cases) and at the Radiotherapy Department of the Ospedale Maggiore, Novara (87 cases) from 1976 through 1984. The series included 29 T1, 88 T2, 64 T3 and 37 T4; 86 patients (40%) were N0. Only 49 patients were stages I and II (1/4 of the total). The local control (T) rate at the end of therapy was 63.5% for the overall series (139/218) ranging from 100% in T1, 72.6% T2, 54.6% T3 to 30% T4; the regional control (N) for patients with cervical lymphadenopathy was 66% (88/132). The overall 5-year survival was 38%; the 5-year disease-free survival was 35%. The 5-year survival according to T-stage was 52% for limited cases (T1-T2) in comparison to 22% for advanced ones (T3-T4). The 5-year survival for N0 stage was 55%; when neck nodes were present (N # 0) the survival was 29% after 5 years. Complications included 6 cases of trismus and 2 osteonecroses of the mandible. Second primary malignant diseases were seen in 17 cases (7.8%). The most common cause of death was failure in primary tumour control (80% of cases). In this series the results of radiotherapy of early stage tonsillar carcinomas are quite good; patients with large tumour masses fare less satisfactorily. Better results should be obtained in the future by identifying prognostic factors, monitoring potential causes of treatment failure and optimizing the radiotherapeutic treatment plan and technique.

Adult↗
PubMed1986

[Comparison of dosimetric protocols for beams of photons and electrons].

In this work we utilize different methods for the calculus of the absorbed dose at different photon and electron energies and we evaluate the difference between their yields. One of these methods is based on the consideration of the factors C lambda e CE (ICRU, HPA, AAPM protocols before 1980); by means of the others (AAPM-Task Group 21, NACP) we seek to obtain a better accuracy introducing new conversion factors. Our measurements were performed using cylindrical and flat ionisation chambers. In the considered energy range we obtained the following results: the new conversion factors have a higher value than C lambda and always smaller than CE.

Electrons↗
PubMedDate not supplied

Prognostic factors of cervical lymph node metastasis in head and neck squamous cell carcinoma.

AIMS AND BACKGROUND: The metastatic spread of squamous cell carcinoma of the head and neck (SCCHN) to the cervical lymph nodes is a negative prognostic factor in terms of survival. We have used multivariate analysis to identify the possible prognostic significance of a number of clinical and pathological characteristics in relation to possible involvement of the cervical lymph nodes in a series of 396 patients. METHOD: 396 patients with SCCHN were studied. Variables regarding the patient, the carcinoma and histology were analysed by multivariate analysis using BMDP's PLR programme. RESULTS: Some variables appear to represent predisposing factors for tumor spread to the lymph nodes: tumor site (supraglottic larynx: P = 0.005; base of the tongue: P = 0.02; hypopharynx: P = 0.02), grading (P = 0.001), and a number of histological parameters (lower degree of histological differentiation: P = 0.001; vascular permeation: P = 0.04; perineural invasion: P < 0.05; prevalently plasmocytic infiltrate: P < 0.05). CONCLUSION: The identification of cases at risk for metastasis can be improved by the assessment of prognostic factors, with a consequent improvement in treatment strategies.

Adult↗
PubMedDate not supplied

Surgery or radiotherapy for early stages carcinomas of the glottic larynx.

AIMS AND BACKGROUND: The choice of treatment in limited squamous cell carcinoma of the glottic larynx often depends on individual and tumor factors. Data of the literature clearly show that surgery and radiotherapy tend to give identical results in terms of survival. We examined 196 cases of T1-T2/N0 cancers of the glottic larynx. We review the literature and discuss the indications and the efficacy of the various available treatments. METHODS AND STUDY DESIGN: 196 consecutive cases of T1-T2/N0 cancers of the glottic larynx were examined. In 54.5% the tumor was confined to the vocal cord; in 38.2% it extended to the anterior commissure, in 4.6% to the arytenoid cartilage and in 2.5% to the floor of the ventricle. We performed partial laryngeal surgery in 41.3% (81 cases). Radiotherapy alone was employed in 58.6% (115 cases). RESULTS: In T1a and T1b cases there was no statistically significant difference in 5-year disease-free survival. In T2 cases the NED survival of patients who underwent partial laryngectomies (90% of cases) was significantly better (P <0.05) than among patients given radiotherapy (73%). NED survival at 5 years in patients with the primary tumor on a vocal cord, ventricle or anterior commissure was 78%, 80% and 81%, respectively, with no statistically significant difference among the various sites. It is possible that involvement of the anterior commissure exposes patients to greater risk of recurrence when radiotherapy alone is used (5 out of 23 cases, 21.7%, compared to 3 out of 52 cases, 5.7%, among our surgically treated patients). CONCLUSIONS: When the tumor is confined to the vocal cord and mobility is not impaired (T1a), surgery and radiotherapy give comparable results, and the latter yields a better functional outcome. When the anterior commissure is involved, recurrences appear to be less likely after surgery. In T2 glottic carcinoma, surgery gives better results than radiotherapy alone. In any event, the choice of treatment should be patient-specific and based on a careful analysis of the factors involved in each case.

Adult↗
PubMedDate not supplied

High prognostic impact of growth fraction parameters in advanced stage laryngeal squamous cell carcinoma.

One hundred and two cases of laryngeal squamous cell carcinoma, all treated in the same center with total or supraglottic laryngectomy, bilateral neck dissection and postoperative radiotherapy, were investigated with both Ki67 and MIB-1 monoclonal antibodies. The aim was to determine the prognostic impact of growth fraction markers in a homogeneous series of patients. All samples were stained with Ki67 monoclonal antibody on frozen sections, and with MIB-1 monoclonal antibody on paraffin sections, using the ABC immunoperoxidase method. The percentage of positive cells was compared in each case with the overall and disease-free survival, pathologic stage and histologic grading. The values obtained from Ki67 and MIB-1 counts were similar and highly correlated (r=0.90). Two groups of cases with low and high proliferation rate (59 and 43 respectively) were obtained by splitting up the whole series, on the basis of the median value; 84. 6% of the patients with high proliferation relapsed and/or died due to the tumor within two years from diagnosis whereas, at time of writing, 94% of the patients with low proliferation are alive and well (p<0.00001). No relation was found between growth fraction and histologic grading, pathologic stage (pT and pN) and site of the tumor. Only lymph node involvement was correlated with disease-free survival. Our results indicate that Ki67/MIB-1 index represents an independent variable to determine long-term prognosis in laryngeal squamous cell carcinomas. We recommend its use in diagnostic protocols, to distinguish high risk subsets of patients who might benefit from more aggressive treatments.

Adult↗
PubMedDate not supplied

Topical role of brachytherapy: economic and organizational aspects.

Brachytherapy for the recent technological advances, represents a fundamental "therapeutic step" in a multidisciplinary approach based on surgery, external beam radiotherapy and chemotherapy, if necessary. The various professionals involved, each within their personal skills, participate in the formulation of a correct therapeutic program. The widespread use of high dose rate brachytherapy leads to consider that the machines should be supplied to major radiotherapy centers only, because the procedure requires the combination with external beam radiotherapy.

Brachytherapy↗
PubMedDate not supplied

[Prognostic factors in the treatment of advanced cervical cancer. A retrospective study].

BACKGROUND: The value of prognostic factors in patients with advanced cervix carcinoma treated by radiotherapy was assessed in a retrospective study. METHODS: From January 1977 through December 1990, 261 patients (average age 60 years) were treated at the Radiotherapy Department of the University of Turin. Distribution by stage was: 142 T2b (54%), 8 T3a (3%), 98 T3b (38%) and 13 T4 (5%). 83% of the patients underwent radiotherapy alone; the total dose was 45-88 Gy in 91 patients (42%) with poor clinical conditions, 60-75 Gy in 121 (56%) and 75-80 Gy in 5 cases. 17% of the patients was treated by surgery combined with radiotherapy. The median follow-up was 50 months (minimum 2, maximum 177 months). RESULTS: The 5-year NED survival and local control were 42% (52% for T2b, 33% for T3 and 15% for T4). The severe (G3-G4) complication rate was very low (1.9%). CONCLUSION: In our series, the prognostic factors which significantly influenced survival in the uni-variate analysis were: advanced T stage, contemporary infiltration of parametrium and vagina, nodal status, non squamous neoplasm, younger age and the absence of brachytherapy in the radiotherapy alone protocol.

Adult↗
PubMedDate not supplied

[Radiologic hyperthermia with microwaves and radio-frequencies. I. Presentation of a multifrequency system].

A computerized system with automatic treatment parameters control for radiological hyperthermia, called Sapic SVO3, is presented. The system has been planned and built by the "Sezione Avionica ed Equipaggiamenti" of the Aeritalia in cooperation with the Radiotherapy Department of the University of Turin. The device is supplied with a multifrequency generator system (915, 433, 2-30 MHz) connected with many kinds of applicators (microstrip antennas, high constant dielectric material loaded antennas, waveguide antennas), with a fiber optic system for temperature control and with a previsional thermometry system.

Computers↗
PubMedDate not supplied

[Mantle irradiation with 18 MeV photons. Measurement and calculation of dose distribution].

Dose distribution in mantle fields irradiated with 18 MeV photons has been studied in an Alderson-Rando phantom with thermoluminescent dosimeters. The treatment was also simulated on an RT-plan 7000 computer; calculated and measured doses in anatomical sites of major interest were compared. Doses in all significant points were within +/- 7% of the doses at the reference point. Calculated and measured doses agreed within +/- 5% except points situated near unhomogeneous tissues. The authors discuss their results and present conclusions about algorithms for computer dose calculation in irregular field treatments.

Computers↗