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Biomedical subjects

B Kimmig

Publications and source records attributed to B Kimmig.

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

[Stereotactic single-dose irradiation of cerebral angioma].

Angiomas are vascular malformations conceived as congenital anomalies. Surgical excision is the treatment of choice; an alternative is embolization. Radiation therapy is indicated: (1) for angiomas in vital or sensitive regions of the brain where they cannot be excised without the risk of a disabling neurological deficit and (2) for residual angiomas after partial embolization or incomplete surgical removal. The most effective radiotherapy for angiomas is radiosurgery. "Radiosurgery" is a term used for a special concept of radiotherapy. It describes stereotactically guided single high-dose irradiation. Therefore, a linear accelerator was modified at the German Cancer Research Center in Heidelberg. The precise localization of the target point and a steep dose gradient outside the target volume allow application of high doses to the tumor without damage to the surrounding normal brain tissue. Since 1984, in Heidelberg 41 patients with cerebral angiomas have been treated by stereotactic single high-dose irradiation (doses: 10-28 Gy). Eighteen patients were angiographically examined with a follow-up period longer than 18 months. In 7 patients, the pathological vessels was completely obliterated and in 6 partially. There was no change in 6 patients - all of whom received target doses of below 12 Gy.

Adolescent↗
PubMed1989

Imaging positron emitting radionuclides generated during radiation therapy.

In vivo generated positron emitting radioisotopes, primarily C-11 and N-13, have been documented following therapy with accelerators larger than 10 MeV. Six patients had positron emission tomography 15 to 25 minutes after radiation therapy with a 42 MeV accelerator. Five patients had recurrent colorectal malignancy, and one required therapy for a carcinoma of the common bile duct. We sought to determine whether state-of-the-art PET technology could be used to monitor the three-dimensional activity distribution of radiation-induced radioactivity. At the time of the examination all six patients had sufficient concentrations of C-11 and N-13 activity in the irradiated volume to permit the evaluation of the activity distribution. We found significant activity at the body surface, which permitted field delineation. We conclude that the in vivo generated radioactivity can be monitored with PET.

Aged↗
PubMed1989

[Diagnosis and therapy of neuroectodermal tumors].

Computed tomography (CT) and 123I- or 131I-meta-iodo-benzyl-guanidine (MIBG) scintigraphy were compared for accuracy in tumor detection in 47 patients with neuroectodermal neoplasms. MIBG concentration was found in 12 of 13 pheochromocytomas, 12 of 12 neuroblastomas, 5 of 9 carcinoids, and 1 of 4 glomus tumors. MIBG uptake was not observed in medullary thyroid carcinomas, oat-cell carcinomas, Merkel tumors, 1 gastrinoma, and 2 unclassified neuroectodermal neoplasms. With regard to the different tumor manifestations, the sensitivity in detecting pheochromocytomas, neuroblastomas, and carcinoids was 87%, 77%, and 100% for CT, and 83%, 100% and 71% for MIBG scintigraphy, MIBG scintiscan was superior in the detection of small adrenal pheochromocytomas (less than 1 cm diameter) and in the depiction of small bone metastases and bone marrow infiltration from neuroblastoma. In all, 25 cycles of high-dose MIBG therapy were performed in eight patients with surgically incurable tumors (4 malignant pheochromocytomas, 1 neuroblastoma, 3 carcinoids). The total therapeutic activity applied was 3.55-43.29 GBq 131I-MIBG. Tumor kinetics of MIBG were investigated before and during treatment. One patient with metastatic pheochromocytoma has been in complete remission for a follow-up period of 36 months since completion of treatment, and another patient is in partial remission. Tumor reduction or no change was observed in four patients. Two patients died of non-concentrating recurrence and metastases.

3-Iodobenzylguanidine↗
PubMed1989

[Computed tomographic diagnosis of diseases of the pituitary region].

Because of the high density and spatial resolution it allows, CT scanning has come to play a key role in the diagnosis of diseases of the pituitary region. While the extension of macroadenomas is regularly detected, only meticulous techniques using coronary scanning following intravenous bolus injection of contrast agent coupled with knowledge of artefacts and normal variations can allow sufficient certainty in the diagnosis of intrasellar lesions. In this respect, the finding of a localized, round hypodense region within the pituitary is of major importance. The so-called indirect signs of a pituitary mass are of minor significance. Demonstrations of typical changes in the CAT scan in combination with the clinical and hormonal findings can contribute to the differential diagnosis of diseases of the pituitary region.

Adenoma↗
PubMed1989

[New radiopharmaceuticals for oncologic diagnosis and therapy: developments in radioimmunoscintigraphy and radioimmunotherapy].

131I labeled monoclonal antibodies are at a disadvantage for radioimmunoscintigraphy due to the in-vivo cleavage of radioiodine by deiodases. Alternative labeling with 99mTc was not very successful because of the lack of suitable ligands for stable technetium complexes. New developments in this field will be presented using stable 99mTc-N2S2 complexes. Some comments on radioimmunotherapy have also been added.

Antibodies, Monoclonal↗
PubMed1989

[Radioiodine therapy and percutaneous radiotherapy of struma maligna].

Effective therapy of thyroid malignancies requires close cooperation between endocrinologists, surgeons and radiologists. Radioiodine offers the unique possibility of curing highly differentiated carcinoma even when it is in a disseminated state. Percutaneous radiotherapy is a proven treatment regimen for residual tumor tissue after surgery and iodine-131 therapy, for locally advanced carcinomas and for recurrences. The controversy surrounding postoperative "prophylactic" radiotherapy in differentiated carcinomas is discussed. The two treatment modalities using ionizing radiation - radioiodine and external irradiation - are reviewed and discussed with reference to indications, techniques, complications and results.

Adenocarcinoma↗
PubMed1989

[Stereotactically targeted radiotherapy of cerebral arteriovenous malformations].

A report is given about radiotherapy in 41 patients suffering from cerebral vessel anomalies. A modified linear accelerator was used in a moving field technique with multiple pendulum planes to apply single doses between 8 and 28 Gy by means of stereotaxis into the angiographically determined target volume. The medium follow-up is 23 months. The latency of radiogenic effects is between one and two years. Radiological controls with an interval of more than 18 months after therapy are available in 17 out of 41 patients. Angiographic investigation showed complete obliterations of pathological vessels in six out of these patients and partial obliterations in six patients; five patients remained unchanged. There were no acute complications. Seven patients presented neurological deficiencies with a latency of 6 to 12 months, however, in all cases but one they regressed completely. Even taking into consideration the small number of patients and the short time of observation, a comparison with the results of other radiotherapeutical proceedings allows to draw the conclusion that the presented technique of stereotaxic convergent-beam irradiation represents a relatively simple, reliable and, in case of precise indication, efficient method for the therapy of cerebral arteriovenous malformations.

Adult↗
PubMed1989

Combined neutron-photon-therapy of locally recurrent rectosigmoidal tumors.

21 patients with unresectable recurrent adenocarcinoma of the rectum were treated with combined photon-neutron radiation therapy. 40 Gy photon were given to the whole pelvis followed by a boost field of 6.6 or 10 Gy utilizing 14 MeV monoenergetic neutrons. The latter was given with an arc therapy technique whereby the dose output fluctuations normally encountered during gantry rotation were compensated for by a computer guided system. All patients had severe pain symptoms before therapy. Twelve patients had a full remission of the symptoms and nine reported considerable relief of pain during follow-up examination. In three patients, further pain symptoms developed after six, seven, and nine months due to renewed tumor progression. In spite of the relative high neutron doses applied, side effects with the arc-technique remained minimal and did not exceed those encountered with photon therapy alone. Although the total follow-up time is relatively short at a maximum of 20 months, with a mean time of 8.5 months, the preliminary results so far are extremely optimistic leading us to further pursue the study.

Adenocarcinoma↗
PubMed1989

[Radiotherapy of primary brain tumors].

Radiotherapy as primary therapy or combined with neurosurgery is a proven treatment modality for brain tumors. Results have been clearly improved by the advances in surgical and irradiation techniques, and the systematic combination of both types of treatment. The indications and treatment techniques are described and a summary of the therapeutic results is given. Brain tolerance and radiation-correlated complications are also discussed.

Adolescent↗
PubMed1988

[Electron therapy of malignant parotid tumors].

Between 1968 and 1984, 61 patients with malignant parotid tumors were irradiated with fast electrons. The irradiation was performed after surgery in 58 patients, 37 out of them had tumor reresidues at the beginning of radiotherapy. The local recurrence rate was 16%, and there were no differences between patients operated in sano and patients operated non in sano. The survival at five years, however, was only 43%. This is explained by the preponderance of tumor histologies with unfavorable prognoses. Distant metastases were observed in 38% of patients. 8/10 patients with local recurrences developed distant metastases. It is noticeable that polymorphous adenomas were found in the anamneses of ten patients and histologically different secondary carcinomas in 9/61 cases.

Adenocarcinoma↗
PubMed1988

[Radiotherapy of locally recurring colorectal tumors. Prognostic factors, follow-up diagnosis and results].

From 1979 through April, 1985, 74 patients were treated by percutaneous irradiation for local recurrences of colorectal carcinomas. The treatment consisted of a contralateral irradiation up to a dose of 40 Gy and a small-volume boost up to 60 to 66 Gy. In case of progressive remote metastases, the treatment was finished at 50 Gy. 53 patients received a dose of 50 Gy or more and were followed for at least six months. The decisive prognostic parameter was the presence of remote metastases when the recurrence appeared (n = 32). The median survival was six months, in patients without remote metastases at this moment it was 15 months. A complete or considerable relief of pain was obtained in 78%; it continued for a median period of 8.5 months, although most of the patients showed a new local tumor progression after an interval of three to 26 months. Computed tomography showed only small regressions or, in most cases, unchanged volumes of the tumors.

Aged↗
PubMed1987

Dihydrofolate reductase-activity in brain tissue. Effect of X-irradiation.

The mechanism responsible for the toxic late effects of cranial irradiation, followed by the administration of systemic methotrexate (MTX) on brain tissue, is still under discussion. We studied the influence of X-irradiation on dihydrofolate reductase (E.C. 1.5.1.3) activity (DHFR), the enzyme inhibited by MTX. New Zealand white rabbits, 6-9 weeks old, underwent 24 Gy fractionated or 20 Gy single-dose brain irradiation using a 60Co source. Before, immediately following, and 1, 2, 4, 12 weeks after irradiation, DHFR was measured in brain and liver tissue by a photometric assay. DHFR in brain tissue was 11.9 +/- 2.9 mU/g wet weight (ww) X h and in liver tissue 121.8 +/- 24.2 mU/g ww X h. Fractionated brain irradiation with 2 Gy per day produced no significant changes in brain DHFR. Single-dose cranial irradiation significantly decreased brain DFHR (7.3 +/- 0.6 mU/g ww X h). Suppression of the developmental increase of DHFR by X-irradiation in young rabbits could be excluded by determining the unchanged brain-to-liver ratios of DHFR in the animals with fractionated brain irradiation.

Animals↗
PubMed1987

[False-positive findings of 67-gallium scintigraphy in staging/restaging of malignant lymphoma].

Gallium scintigraphy has been an established method for the diagnosis of malignant lymphomas for some years. If properly interpreted, the value of the method is not necessarily reduced by the lack of tumour specificity and the well known property of 67Ga to accumulate in inflammatory and granulomatous conditions. A retrospective analysis of 123 patients with malignant lymphomas showed false positive 67Ga scintigrams in 7%. These cases demonstrate the spectrum of possible errors. 'False positives' were all those localised areas of uptake which were due to some pathological condition which was not lymphomatous. All the positive gallium findings could be elucidated by clinical, radiological and histological investigations.

False Positive Reactions↗
PubMed1987

Perspectives of radiotherapy.

The 5 years' survival rate of all cancer patients is 35-45%. In that survival rate radiotherapy takes part in 15%. By further development of radiological methods and techniques radiotherapy gains significance in the recent time. Optimizing radiation planning and tactics, all modern imaging techniques are applied consequently. The radiotherapist must be able to asses their immanent specifity which should remain object of the radiological training, even if separated into therapy and diagnostics. Dose distribution is calculated by computer; three-dimensional planning is done in tumors of the mediastinum, oesophagus carcinoma and paraaortic lymphomas. Critical description of radiation techniques, results, problems and prognoses are given by results in tumors of the epipharynx and gastric cancer. After-loading, done until now only in gynaecological tumors, is performed in recurrences of pharyngeal tumors by individually shaped applicators. Reducing the number of therapy failures as well as possible, the application of higher tumor doses, new kinds of rays as neutrons and combinations with physical and chemical methods is outlined. Modifications of radiation volumes are discussed, especially the irradiation of the complete abdomen in ovarian cancer, the irradiation of the complete body surface by electrons in mycosis fungoides, and the total body irradiation prior to autologue bone marrow transplantation. Modifications of fractionation are shown in short-time radiation of bone metastases and single-time radiation of brain lesions. Low penetrating electron therapy facilitates intraoperative single-time irradiation. Because of higher biological efficiency neutrons and heavy ions allow to irradiate low sensible tumors or recurrences embedded in fibrotic tissue respectively. The combination with hyperthermia yields good results in tumors of the head and neck with better local response and total remissions of 59%. There are potentials in synchronising with chemotherapeutics. Remissions of different duration were achieved in 190 patients. Because of neutrotoxicity there are still problems in applicating radiosensitizers. New methods are applied treating endocrine active tumors by labelled hormone precursers.

Brachytherapy↗
PubMed1987

[Role of 131I-metaiodobenzylguanidine scintigraphy in the diagnosis of intestinal carcinoids].

Iodine-131 metaiodobenzylguanidine (131I-MIBG) is concentrated in a variety of neuroendocrine tumors, such as pheochromocytoma and neuroblastoma. Other neuroendocrine tumors from the APUD-cell system such as carcinoid tumors, may possess this uptake capability as well. We investigated 11 patients suffering from intestinal carcinoid with 131I-MIBG in order to determine the value of MIBG scintigraphy in these tumors. MIBG scans were positive in 5 out of 11 patients (45%). False-positive MIBG-scans did not occur. No correlation between MIBG uptake, clinical symptoms and urinary 5-HIAA level could be found.

3-Iodobenzylguanidine↗
PubMed1987

[Results of radiation therapy in brain metastases with reference to computerized tomography].

Between 1979 and 1985, 193 patients were submitted to radiotherapy of the brain for formation of metastases. A primary irradiation was performed in 159 patients, 34 patients had been treated by surgery. The median survival time after diagnosis of all irradiated patients (40 to 60 Gy within four to six weeks) was 4.9 months, 22% of the patients survived one year. Patients with mammary carcinomas and patients with bronchial carcinomas showed marked differences in median survival times (4.2 and 6.9 months, respectively) and one-year survival rate (11% and 32%, respectively). In histologic examination, the extent of extracerebral formation of metastases was the decisive parameter for survival. At the end of radiotherapy, 47% of patients showed an amelioration in neurologic deficiency, 16% deteriorated. A follow-up by computed tomography with observation periods between four and 34 months was possible in 84 patients. Most of these patients showed improvement in computed tomography during a period of four to twenty weeks after the beginning of radiotherapy. Later on, about two thirds of the controlled patients had again deterioration with local progression or new formation of metastases in spite of total brain irradiation. A long-term normalization (greater than one year) was observed only in patients with mammary carcinomas.

Brain Neoplasms↗
PubMed1986

Iodine-131-labeled diphosphonates for the palliative treatment of bone metastases--III. Considerations of interaction, binding and absorbed dose.

General considerations about the possible mechanisms of action of rather low dose ionizing radiation with bone metastases and stimulated nerve fibers reveal that only minute amounts of chemicals are produced by direct interaction of energetic electrons. Thus changes of the chemical milieu due to direct interaction must be ruled out in favour of a radiation-induced trigger reaction which may then initiate a cascade of cellular responses. Organ distribution studies of a series of radioiodinated benzylidenediphosphonates with H-, HO- and H2N- in the alpha- and p-position revealed best results for pHO-NH2 (BDP3). The microscopic distribution of 131I-DBP3 in bone tissue was monitored by autoradiography. Elevated uptake in normal (tibia) and neoplastic bone (experimental osteosarcoma) corresponded with the degree of vascularization and formation of new hydroxylapatite. Unlike the uptake in human osteoblastic bone metastases the experimental osteosarcoma of SD-rats accumulated 131I-BDP3 less than normal bone. This was due to the short volume doubling time, the delay of hydroxyl-apatite deposition and the formation of necroses. Theoretical replacement of 131I in iodinated BDP3 with radioisotopes emitting higher energy electrons yielded best bone metastasis/organ ratios for 32P labeled BDP3. The bone metastasis/bone marrow dose ratio by comparison with 131I labeled BDP3 is, however, almost equal. The isotopes 130I and 133I are not suited to the achievement of higher tumor/background doses although they are higher energy beta- -emitters than 131I. Because of their short physical half life and absence of different kinetics in normal and neoplastic bone no dose enhancement in bone metastases can be attained.

Animals↗