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B Kimmig

Publications and source records attributed to B Kimmig.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Daylight processing system in radiotherapy. Technical changes and cost benefit analysis].

BACKGROUND: In radiotherapy portal and verification imaging take an important place in daily quality assurance procedures. Different types of films and cassettes have to be used to gain an optimal result for photon and electron beams. MATERIALS AND METHODS: We describe a modification of a machine for daylight processing, which has been technically enabled not only to process all X-rays from simulator, brachytherapy, CT and MRI but all film materials from portal and verification imaging as well without changing system's configuration. Using a light gap, verification films are automatically differentiated from portal films or from film material from simulation and the cassettes are automatically loaded with the new verification film. Furtheron, we took some attention on cost effectivity. RESULTS: The daylight processing machine is sufficiently integrated into daily routine work load and spares a lot of staff time. Higher primary costs are overbalanced within a few years by lower supporting costs (Table 1). This is especially due to lower film material costs (Table 2), but also a result of staff time reduction. CONCLUSIONS: Radiotherapeutic departments may gain much comfort using a daylight processing machine as development unit.

Brachytherapy↗
PubMed1996

[Validity of bone scintigraphy for radiotherapy treatment planning of the skeletal system].

Aim of this paper is to assess the validity of bone scanning for radiation therapy treatment planning in the skeletal system. Radiation therapy treatment planning in the skeletal system is based on plain film radiographs and bone scanning. Between January 1, 1993 and June 30, 1994, 228 patients were irradiated due to malignancies in the skeletal system. Included were bone metastases, lymphomas, sarcomas and bone invasion of neuroblastoma. The morphological display of the plain film radiographs and the bone scintigraphies were compared and modifications of the target volume due to the scan findings quantified. In 17 of 228 patients (7.5%) the target volume was modified by at least 2 cm due to tumor invasion depicted by radionuclide scanning only. Bone scintigraphy enables a sensitive display of bony invasion in skeletal malignancies. Because of a scan induced alteration of the target volume in 7.5% of the cases, bone scanning cannot be abandoned in RT treatment planning.

Bone Neoplasms↗
PubMed1996

[The results of strontium-90 contact therapy to prevent the recurrence of pterygium].

AIM: Aim of the study was the evaluation of the role of adjuvant radiation therapy in the prevention of recurrence after excision. PATIENTS AND METHODS: Between July 1, 1985 and April 1, 1993, 64 patients (43 male, 21 female) were referred to radiation therapy after excision of a nasal pterygium. Radiation therapy was done with a strontium-90 eye applicator and a total dose of 30 Gy, fractionated in 6 fractions of 5 Gy each, 3 times a week. Forty-nine patients were treated primarily, 15 patients underwent radiation therapy for the first time in case of recurrent pterygium after multiple re-excisions. All patients had a following of 1 to 9 years with a median of 5.5 years. RESULTS: In 8 of 64 irradiated patients recurrent pterygium was detected (12.5%). Differentiated into the 2 groups 4 of the primarily treated patients had recurrent pterygium (8.16%), the other 4 were in the group with multiple former re-excisions (26.7%). With regard to the initiation of the irradiation after surgery pterygium did not recur in any of the primarily treated patients who were irradiated in between 3 days after surgery. In contrary 3 of 7 primarily treated patients (42.9%) who started radiation therapy between 7 and 10 days after surgery had recurrent pterygium. For the patients with primarily recurrent pterygium no dependence of the initiation of radiation therapy after surgery could be detected. CONCLUSIONS: Adjuvant radiation therapy after excision of pterygium lowers the rate of recurrence from about 40% to 12.5%, in a primarily adjuvant situation to 8.16%. In these patients radiation therapy should be initiated within 3 days after surgery. Patients with primarily recurrent pterygium have an elevated risk of recurrence independently of the initiation of radiation therapy.

Adult↗
PubMed1996

Conformal treatment planning for interstitial brachytherapy.

PURPOSE: Quality of a brachytherapy application depends on the choice of the target volume, on the dose distribution homogeneity and radiation injury on critical tissue, which should be postulated by advanced brachytherapy treatment planning systems. MATERIAL AND METHODS: Basic imaging method for conformal treatment planning is the cross-sectional imaging. The clinical applicability of a new type 3D planning system using CT and/or MRT-simulation or US-simulation for planning purposes was studied. The planning system developed at Kiel University differs from usual brachytherapy planning systems because of the obligatory use of cross-sectional imaging as basic imaging method for reconstruction of structures of interest. Dose distribution and normal anatomy can be visualized on each CT/MRT/US slice as well as coronal, sagittal, axial and free chosen reconstruction (3D), as well as dose-volume histogram curves and special colour-coded visualization of dose homogeneity in the target can be analyzed. RESULTS: Because of the experience in the clinical routine, as well as on the base of 30 simultaneous planning procedures on both 2D (semi-3D) and 3D planning systems we observed similar time consumption. Advantages of 3D planning were the better interpretation of target delineation, delineation of critical structures as well as dose distribution, causing more accurate volume optimisation of dose distribution. CONCLUSION: Conformal brachytherapy treatment planning for interstitial brachytherapy means significant advantages for the clinical routine compared to 2D or semi-3D methods.

Algorithms↗
PubMed1996

Results of adjuvant radiation therapy after surgical excision of pterygium.

The aim of the present study was the evaluation of the role of adjuvant radiation therapy in the prevention of recurrence after excision. Between July 1, 1985, and April 1, 1993, 64 patients (43 men, 21 women) were referred for radiation therapy after excision of a nasal pterygium. All patients were followed for 1-9 years (median 5.5 years). Radiation therapy was done with a strontium 90 eye applicator at a total dose of 30 Gy fractionated into six fractions of 5 Gy each. In all, 49 patients were treated after their first excision and 15 patients had undergone multiple prior excisions. In 8 of 64 irradiated patients, recurrent pterygium was detected (12.5%); 4 recurrences developed after first excision and adjuvant radiation therapy (8.16%) and the other 4, following multiple former reexcisions and radiotherapy (26.7%). Pterygium did not recur in any of the primarily treated patients who were irradiated within 3 days of surgery. In contrast, 3 of 7 accordingly treated patients (42.9%) who started radiation therapy at between 7 and 10 days after surgery developed recurrent pterygium. Adjuvant radiation therapy after excision of pterygium lowers the overall rate of recurrence to 12.5%. In an adjuvant situation after first excision, radiation therapy should be initiated within 3 days of surgery, the result being freedom from recurrence.

Adult↗
PubMed1995

[The use of contrast media for quality assurance in radiotherapy planning].

PURPOSE: The target volume definition in radiation therapy was evidently improved by CT and MRI. Basis of treatment planning, however, remains the therapy simulator. Important instruments for adequate fluoroscopic treatment planning are contrast media that recently have been applied less out of legal and professional reasons. Aim of this work is to evaluate the possible benefit of contrast media applications. PATIENTS AND METHODS: In 1303 simulations between 1.1.1993 and 30.9.1993 105 times intravenous contrast media were applied, supplied by oral or endolymphatic contrast agents. It was studied if the previously intended plan had to be altered due to contrast media application. RESULTS: In 17 out of 105 cases (16.2%) the target volume or the preplanned technique had to be altered after contrast media application. Main reason was the existence of anatomical variations especially in kidney and small bowel detected by use of contrast agents. So standard indications for contrast media applications were defined. CONCLUSIONS: Contrast media are an important tool in treatment planning that should be orientated on diagnostical standards. Applications of contrast agents facilitate the detection of anatomical variations and the selection of the appropriate technique in order to shield sensitive tissues. The therapeutical and legal benefit outweigh potential hazards due to intolerances or professional obstacles.

Contrast Media↗
PubMed1992

[MR tomography and MR angiography--a new method for the planning of the irradiation of large abdominal fields].

Subdiaphragmatic radiation therapy in malignant lymphoma requires complete irradiation of retroperitoneal lymph nodes, spleen and splenic pedicle and optimal shielding of radiosensitive structures. The aim of our study was to develop a new method for individual field definition by using MR tomography and MR angiography. In 38 patients with malignant lymphoma coronal MR tomograms and MR angiograms of the abdominal vessels were obtained and superimposed by a specially created computer program. By using a Subtraskop the MRT/MRA superposition was geometrically projected onto the simulation film in correct scale. The target volume could individually be defined and was compared to standard treatment planning according to the definition by Abbatucci. In all patients an exact irradiation of the spleen, the splenic pedicle and prominent lymphatic masses was possible. Furthermore, this resulted in a 32% reduction of treated kidney volume in the average of patients. Noninvasiveness, acceptable costs and high accuracy support the application of this new method in clinical routine.

Abdomen↗
PubMed1992

[Stereotactic convergent-beam irradiation: its current prospects based on clinical results].

"Radiosurgery" is the term for a special concept in radiotherapy. It describes a percutaneous, stereotactically guided irradiation delivering a single high dose with collimated narrow beams. The precise stereotactic localization of the target point and a steep dose gradient outside the target volume allow the administration of high doses to a lesion without damage to adjacent normal tissue. Risk of necrosis, due to a dose volume relationship represents the limits of radiosurgery. Units for radiosurgery were designed at Stockholm using multiple external cobalt-60-gamma sources, at Boston operating with protons of a cyclotron, at Berkeley operating with helium ions accelerated by a synchrocyclotron. An attractive alternative to these complicated and expensive facilities is the use of a modified linear accelerator. At the German Cancer Research Center in Heidelberg such a system was developed and has been available for the treatment of patients since 1984. Though, data of over 100,000 patients with vascular malformations and cancer disease are available worldwide, the indication for this therapy is validated only for a minority of entities. In cases of inoperable arteriovenous malformations favourable results in achieving obliteration range between 60% and 100% were obtained. Median survival for solitary brain metastases with controlled, extracerebral tumor diseases were between nine and twelve months. Up to now, advantages of stereotactic irradiation for benign tumor masses could not be proven. Therefore, randomized trials should be initiated in this field, considering decisive improvements in local tumor control with techniques of microsurgery and fractionated, postoperative radiotherapy during the last few years.

Brain↗
PubMed1991

Radiosurgical treatment of cerebral metastases. Method, indications and results.

Stereotactically guided single-dose irradiation of brain metastases with low radiosensitivity has been performed in a series of 30 patients. Clinical symptoms improved in 18 of 27 evaluated patients and remained stable in another 7. Tumour regression was achieved in 13 of 22 patients, and arrest of tumour growth in 7 other patients. The treatment was usually well tolerated. The incidence of side effects was low. Thus, radiosurgery seems to be a valuable alternative to microsurgical extirpation of solitary brain metastases with low radiosensitivity.

Adult↗
PubMed1991

[Comparison of dosimetric properties of 15-MV-photons and 14-MeV-neutrons in external stereotaxic convergence therapy].

Dosimetric properties for stereotaxic convergent beam therapy techniques with small field sizes have been investigated as well as for the linear accelerator Mevatron 77 as for the neutron generator KARIN. Additionally we also measured the dose distribution of single plane rotational therapy. As an indication of quality we calculated the V50 ratio as V50 = (F50-F90)/F90 and the corresponding V20 values. For the single plane irradiation there is a considerable difference in dose distribution in favour of photons. V50 (axial) amounts to 1.77 for photons and to 2.7 for neutrons. For the convergential non coplaner arc-therapy using nine plans there is nearly no difference in the high dose region including the 50%-isodose. V50 (axial): 1.16 and 1.6 respectively; (frontal) 1.36 and 1.35 respectively. Regarding to physical dose distributions our results indicate, that 14-MeV neutrons are suitable for high dosed stereotactic single irradiations.

Brain Neoplasms↗
PubMed1990

Quantification of subcutaneous fibrosis after combined photon neutron therapy.

Subcutaneous fibrosis is intensified for neutron therapy compared with photon irradiation. It can be a dose limiting factor. Quantification of subcutaneous fibrosis is possible using CT scans and measuring the tissue density in Hounsfield units. With this technique the time dependent development of fibrosis after neutron irradiation was determined in ten patients, who had been treated for recurrent recto-sigmoidal tumors.

Adenocarcinoma↗
PubMed1990

Photon-neutron therapy for recurrent colorectal cancer--follow up and preliminary results.

26 patients with unresectable locally recurrent adenocarcinoma of the rectum were treated with a mixed beam schedule. 40 Gy photons were delivered to the whole pelvis followed by a neutron boost of 6.6 or 10 Gy. Neutron therapy was carried out with a 14 MeV d-t generator (KARIN) using an isocentric are technique. Fluctuation in neutron dose rate during irradiation was monitored by a computer which controlled the gantry speed. All patients were followed clinically by CEA monitoring and CT-scans. In 18 patients positron-emission-tomography (PET) was used to verify the therapeutic efficacy. All patients were symptomatic with severe pain prior to therapy. After a mean follow-up interval of 12.8 months (range six to 26 months), the palliative effect in terms of pain relief was excellent in 22 patients in spite of the poor general condition of most patients and the large tumor extension. In four patients, further pain symptoms developed again after six to nine months due to renewed tumor progression. We observed proctitis at late side effects in one, enteritis in two and a fistula in one patient six to ten months after therapy. Changes in tumor glucose metabolism were monitored by serial PET examinations in all patients. The typical pattern observed by PET was a decrease in the F-18-Deoxyglucose (FDG) accumulation, approximately six weeks after onset of therapy.

Adenocarcinoma↗
PubMed1989

Recurrence of colorectal tumors: PET evaluation.

Positron emission tomography (PET) was used in the follow-up of patients with colorectal malignancies to differentiate between recurrent colorectal tumor and scar. Patients were examined with oxygen-15-labeled water and with fluorine-18-labeled deoxyglucose (FDG). FDG was injected intravenously to assess tumor metabolism. The tracer concentration was quantitatively evaluated by means of a region-of-interest technique and standardized for both injected dose and body volume. Of 29 patients, 21 had recurrent colorectal malignancy, and eight had a nonmalignant mass. All malignancies were seen on the PET cross sections. Nonmalignant lesions had a low FDG accumulation on images obtained 60 minutes after injection. While the tumor-soft tissue ratio was highest shortly after the intravenous injection of FDG, the tumor-scar ratio was highest 60 minutes after injection. It was possible to differentiate tumor from non-malignant tissue with FDG with the use of standardized concentration values and tumor-soft tissue ratios. Imaging with O-15-labeled water gave no additional information.

Adult↗
PubMed1989

[Radiotherapy using photons and neutrons in recurrences of colorectal tumors].

74 patients with locoregional recurrences of colorectal carcinomas were subjected to radiotherapy with photons. In 72% of the patients a palliative effect was seen with considerable or complete pain relief. The median survival times of the patients with and without remote metastases were 7 and 15 months, respectively. Radiobiological experience leads us to expect a higher degree of efficacy when using highly ionising radiation such as neutrons. The relatively poor physical parameters of conventional neutron generators were optimised by means of a novel irradiation technique developed at the German Research Centre in Heidelberg. Using this technique, a study was started for the combined photon/neutron irradiation in recurrent sacral tumours. 14 MeV neutrons of a DT (deuterium-tritium) generator ("KARIN" supplied by Haefely) were applied as boost. 26 patients have so far been treated by this method. Palliative results are excellent and the results obtained so far have been so encouraging that an extension of the study is under consideration.

Cobalt Radioisotopes↗