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W Alberti

Publications and source records attributed to W Alberti.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Video technology and the personal computer in the therapy simulator].

PURPOSE: Technical progress in the development of radiation therapy simulators provided valuable addition of electronically stored images and monitor indicators for individual radiation parameters. One can store as well as print these data as a treatment plan. The possibility of supplementing older simulators with these technical options will be reported in the following paper. METHODS: The modification of our simulator installation was done simply. The new equipment needed to expand our simulator facility was almost exclusively derived from the fields of entertainment and home electronics (Visualizer/video camera, video tape recorder, video mixer, additional monitor; personal computer and printer). RESULTS: With these modifications we reached the technical standards of the latest simulator generation. In addition, we succeeded in implementing additional technical options: e.g. image inversion with contrast alignment to diagnostic displays, complete magnetic tape recording of the entire x-ray process with possible repetition, electronic overlapping of the simulator image and the diagnostic image (e.g. NMR; angiograms) to determine the treatment volume, automation in x-ray documentation. CONCLUSION: Increased precision and rational work steps employing readily available equipment will lead to further improvement in the quality of radiotherapy.

Computer Systems↗
PubMed1993

Solid phantom material for the dosimetry of iodine-125 seed ophthalmic plaques.

PURPOSE: A tissue-equivalent solid phantom material, RE-1, closely simulating the radiological attenuation and scattering properties of the human eye for the iodine-125 photon spectrum and their Compton-scattered secondary photons, was fabricated on a polyethylene base with CaCO3 and MgO as inorganic additives. METHODS AND MATERIALS: A 24 mm diameter spherical phantom was made from 1.1 mm thick sheets of RE-1, and holes were drilled in which 1 mm3 TLD cubes were placed. RESULTS: The radial dose function g(r), which determines the dose profile on the transverse axis, was measured in a quasi-infinite phantom of RE-1. CONCLUSION: The values obtained deviate only slightly from those for a quasi-infinite phantom made from water-equivalent material.

Brachytherapy↗
PubMed1993

Autoradiography for iodine-125 seeds.

To study the interior design of model 6702 and 6711 iodine-125 seeds contact autoradiographs were performed using mammography film. Improved resolution was obtained using a pin-hole camera with a hole of 0.1 mm x 0.1 mm. With these techniques, qualitative determination of the relative activity distribution within each seed was possible. The number of the activated resin spheres and the positions of the centers of these spheres can be exactly determined. A model calculation shows, that variations in the arrangement of the activated spheres within a seed have a moderate influence on the dose distribution at source distances below 10 mm. Knowing the exact source configuration may be useful when comparing dose calculations with measured data for model 6702 125I seeds which are currently employed in ophthalmic plaque and implant therapy of other tumors.

Autoradiography↗
PubMed1991

Dosimetry and physical treatment planning for iodine eye plaque therapy.

The dosimetry of eye plaques loaded with iodine-125 seeds (type 6702) was performed by means of computer calculations and measurements with thermoluminescent dosimeters (TLD). Measurements of the depth dose distribution (2-25.5 mm) along the transverse axis of a single seed were performed in water equivalent phantom material. The transverse axis attenuation and geometry factor F(r) was obtained by applying a least squares fit to the measured data. Based on the resulting radial dose function, a computer program was developed which calculates dose distributions within the eye for arbitrary loading and placement of the eye plaque. The computational results were verified by TLD measurements in an eye phantom.

Brachytherapy↗
PubMed1991

Complications associated with brachytherapy alone or with laser in lung cancer.

Relatively little has been reported about destruction through brachytherapy of mucosa-perforating and extraluminary tumors with probable large vessel involvement causing major hemorrhagic or fistular complications. We report 12 patients subjected to laser and brachytherapy for centrally occluding lung cancer, whom we have periodically followed up from June 1986 until they died. Although all laser procedures were free from complications, necrotic cavitation in five cases, two of which were accompanied by large bronchoesophageal fistulas, and massive fatal hemoptysis occurred in six. Minor complications included radiation mucositis (two), noncritical mucosal scarring (two), and cough (four). Characteristics that will identify patients at risk of developing fatal hemoptysis and fistulas should be better defined by imaging and endoscopic techniques. In such cases, modifying the protocol or using alternative procedures should be considered. Minor complications, such as cough, can be avoided by using topical steroid therapy (eg, beclomethasone dipropionate).

Adult↗
PubMed1990

[Development and dosimetry of a 125 iodine applicator for brachytherapy of intraocular tumors].

Due to the low gamma energy (27-35 ke V), iodine 125 is especially suitable for brachytherapy of intraocular tumors. 125I is available as encapsulated seeds. Applicators can be individually loaded with these seeds to accommodate the shape of the tumor as much as possible. To measure the depth-dose distribution LiF thermoluminence detectors (TLDs, 1 mm3) are embedded in an RW-1 eye phantom at various distances and directions from the high active plaque positioned at the top of the phantom. To obtain the three-dimensional dose distribution, the TLDs are read after exposure for the appropriate time period. Based on experimental measurements of the 125I plaque, a computer program is developed to calculate the dose distribution within the eye and the radiation time for intraocular tumors. These results are very similar to those obtained when using mathematical equations published in the literature. In summary, three-dimensional dose distribution at various distances from an 125I eye plaque has been experimentally determined using a new method. This is an important prerequisite for introducing 125I plaques into the treatment of intraocular tumors.

Brachytherapy↗
PubMed1989

[Sequential induction chemotherapy and radiation treatment of inoperable small cell bronchial cancer. Results of a prospective randomized study].

To study the potential benefit of sequential chemotherapy in inoperable small cell lung cancer (SCLC), from 1982 to 1986 ninety-one patients with histologically proven and previously untreated SCLC (median age: 53 years; median Karnofsky status: 80%) were randomly assigned to an initial therapy with adriamycin (since 1984 epirubicin), cyclophosphamide, vincristine (ACO resp. EPICO) or etoposide/cisplatin (VP16/DDP). Treatment courses were repeated every 3 weeks for a total of less than or equal to 6 courses with a crossover after a maximum of 3 cycles of either regimen. Limited disease (LD) patients with bronchoscopical, computertomographical and (re-) mediastinoscopical complete remission (CR) randomly received either a thoracic irradiation with 40 Gy or observation only. Overall, 60 out of 85 evaluable patients achieved an objective remission. A CR was observed in 24/51 patients (47%) with limited disease, and in 8/34 patients (24%) with extensive disease. Both, ACO (EPICO) and VP16/DDP were equally effective as initial and second-line therapy. Moreover, after failure to the initial therapy an objective remission could be achieved in 13% of the patients following the alternative second line combination. In 28% of LD patients with an otherwise complete remission residual tumor was detected by (re-) mediastinoscopy. Median survival times were 14 (CR: 16) months in LD patients and 10 (CR: 15) months in ED patients. At present, median survival is significantly improved in irradiated versus non-irradiated LD patients (25 vs. 13 months, p less than 0.04). The remission rates and median survival times observed in this study are comparable to those of a historical control group treated with ACO plus radiotherapy alone.

Adult↗
PubMed1989

[Dosimetry of ruthenium applicators with an eye phantom and small volume thermoluminescence detectors].

Even though 106Ru/106Rh applicators have been in clinical use over more than two decades for the radiotherapy of malignant uveal melanomas, the dosimetry of emitted beta radiation is still a physical problem. The dose rate at the applicator surface and the depth dose in tissue equivalent material can be determined only within +/- 30% error. Using new cubic-shaped thermoluminescence detectors (TLD) with small volume the dose distribution is examined in water equivalent material (RW-1). The spatial resolution is 14 times better compared to the previous technique. From dose measurements in an eye phantom the homogeneity of nuclide deposition and the depth dose distribution of a 106Ru/106Rh applicator are determined.

Brachytherapy↗
PubMed1987

[Non-ocular, malignant secondary tumor following spontaneous healing of a retinoblastoma ("retinoma", "retinocytoma")].

In a 47-year-old patient, the father of a child with bilateral retinoblastoma, three retinomas or retinocytomas were observed in the right eye, which had never been treated, in the course of a routine checkup. The left eye had been enucleated at age three-and-a-half because of a tumor of unknown etiology. At age 55 the patient died of lung cancer. The autopsy revealed a metastasized small-cell bronchial carcinoma. Histopathological examination of the right eye showed, in the region where the tumors had been observed clinically, merely disorganized retinal tissue with proliferations of pigment epithelium in some areas, and well-differentiated retinoblastomas in others. Tumor regression and differentiation appear to be the mechanisms responsible for spontaneous healing of the retinoblastoma. This case also emphasizes the threat posed by non-ocular secondary tumors to carriers of retinoblastoma genes.

Calcinosis↗
PubMed1987

The prognosis of retinoblastoma in terms of globe saving treatment. A computer assisted study. Part I.

At present there is no satisfactory classification or staging system. In order to compare the Reese classification (Reese & Ellsworth, 1963), the Essen classification (Höpping, 1983) and a new classification, a method of evaluating different parameters was created to get an optimal classification of globe saving treatment. A computer score table for the Essen eye clinic was established and this table could be valuable for all clinics using modern methods of treatment.

Decision Making, Computer-Assisted↗
PubMed1986

[Indications for and results of postoperative radiotherapy of vulvar cancer].

Between 1968 and 1979, 132 patients with squamous cell carcinomas of the vulva were submitted to a more or less radical operation. Then they were irradiated at the Radiologic Center of the GHS Essen. All patients received irradiations of the vulvar region with high energy electrons combined with photons (n = 78) as well as photons or electrons alone (n = 15 and 39, respectively). The dose was generally 40 to 60 Gy. 81 patients (61.4%) were additionally irradiated in the inguinal region. The overall three-year and five-year survival rate is 48.5 and 34.1%, respectively. The median survival time is 31.5 months. Contrary to expectation there were no significantly different recurrence rates after radical vulvectomy and large excision combined with postoperative irradiation. This is attributed to the favorable effect of radiotherapy. A graduated conception has been elaborated based on the results of our retrospective analysis and the communications of literature. Radical vulvectomy and inguinal lymphadenectomy is the therapy of choice. Radiotherapy in the vulvar region should be applied if radical surgery seems problematic or is not possible. Irradiation of lymph node regions is indicated if they are involved or if a resection is not possible.

Adult↗
PubMed1985

Bone marrow transplantation for chronic granulocytic leukaemia.

Twenty-one patients with chronic granulocytic leukaemia underwent marrow transplantation. The donors were human-lymphocyte antigen-identical siblings in 19 cases. In the remaining 2 cases the donor was a parent in one and an identical twin in the other. The preparatory regimen included cyclophosphamide and 8.6 Gy total body irradiation given at either a dose of 0.1 Gy/min or 0.04 Gy/min. Five patients were in the accelerated phase of the disease, one was in remission following blast crisis, and the rest were all in the chronic phase. After chemotherapy and irradiation, all patients received bone marrow transplants. To date, nine patients are still alive, with a median survival of 64 days (range 28-683 days). One patient continued to have leukaemic cells and in another, the leukaemia recurred 18 months following transplantation. Interstitial pneumonitis was the cause of death of eight patients (38%). Graft-versus-host disease occurred in ten patients (47%).

Adolescent↗
PubMed1985

[Combined chemotherapy and radiotherapy: cyclophosphamide].

Compared to the other chemotherapeutic preparations discussed today, cyclophosphamide in combination with radiotherapy is a relatively unproblematic substance. Despite the great number of experimental and clinical data, the evaluation does not prove an advantage of the combined therapy with cyclophosphamide and irradiation as against radiotherapy alone in local tumor treatment. This should give occasion to further experimental investigations in adequate models. On the other hand, the practice of combined treatment with irradiation and preparations containing cyclophosphamide should be reconsidered for those cases where local control of a tumor is the principal therapeutic aim.

Animals↗
PubMed1985

[Prognostic factors during control of the course of lymphogranulomatosis: comparison of 2 therapy technics and analysis of serologic parameters].

Between 1970 and 1980, 339 patients with Hodgkin's disease in stages IA to IIIB were treated at the Department of Radiotherapy, University of Essen, FRG. 65 patients (group A) were irradiated using a multiple-field-technique with cobalt-60, 110 patients (group B) with mantle fields, inverted Y or paraaortic extended fields given with 5.7 MeV photons. There were no significant differences between the cumulative survival times, local and marginal recurrences. However, the recurrence rates of unirradiated lymph node regions were different, mainly due to absent or given paraaortic treatment. The presence of initially normal blood parameters (BSR, relatively lymphocyte count, haptoglobin, copper, iron) is of high prognostic value. Combined, they allow a correct prognosis as to the five year recurrence rate in up to 98% of cases. The prognostic precision of initially pathologic values was considerably reduced, even if a normalization had occurred after one year from the initiation of treatment.

Cobalt Radioisotopes↗