[A frameless method for stereotactic radiotherapy].
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Humans↗
Biomedical subjects
G Gademann
Publications and source records attributed to G Gademann.
[Radiotherapy of prostatic cancer].
In most cases, surgery and radiotherapy are used for primary local treatment of prostate carcinoma. The treatment decision depends to varying extents on the involvement of the two clinical fields urology and radio-oncology. Radiotherapy seems to have more weight in the treatment of prostate carcinoma in the USA than in Germany, albeit with local differences. For the early stages prospective observation of the tumour is recommended. Surgery, as far as possible nerve conserving procedures, is indicated for localized tumours with no infiltration of the capsule or seminal vesicles. This does not mean that the clinical results after radiotherapy are worse in these patients. With both treatment modalities the survival data are comparable with those in a healthy population. Surgery is limited to the exploration of the pelvic lymph nodes in the stages C and D1. Radiotherapy has been shown to be effective in these tumours, but is still not satisfactory, with a relapse rate of ca. 30% for stage C after 10 years. This means new research and developments are necessary in conformation radiotherapy, neutron therapy, brachytherapy and hyperthermia. Side-effects after radiotherapy are rare, with late complications in only a low percentage of patients. Recurrences after radical prostatectomy can be followed for at least 5 years without evidence of disease. Radiotherapy has a good palliative effect in bone and brain metastases.
Brachytherapy↗
Renal tolerance to nonhomogenous irradiation: comparison of observed effects to predictions of normal tissue complication probability from different biophysical models.
PURPOSE: A patient series was analyzed retrospectively as an example of whole organ kidney irradiation with an inhomogenous dose distribution to test the validity of biophysical models predicting normal tissue tolerance to radiotherapy. METHODS AND MATERIAL: From 1969 to 1984, 142 patients with seminoma were irradiated to the paraaortic region using predominantly rotational techniques which led to variable but partly substantial exposure of the kidneys. Median follow up was 8.2 (2.1-21) years and actuarial 10-year survival (Kaplan-Meier estimate) 82.8%. For all patients 3-dimensional dose distributions were reconstructed and normal tissue complication probabilities for the kidneys were generated from the individual dose volume histograms. To this respect different published biophysical algorithms had been introduced in a 3-dimensional-treatment planning system. RESULTS: In seven patients clinical manifest renal impairment was observed (interval 10-84 months). An excellent agreement between predicted and observed effects was seen for two volume-oriented models, whereas complications were overestimated by an algorithm based on critical element assumptions. CONCLUSIONS: Should these observations be confirmed and extended to different types of organs corresponding algorithms could easily be integrated into 3-dimensional-treatment planning programs and be used for comparing and judging different plans on a more biologically oriented basis.
Adult↗
Stereotactically guided fractionated radiotherapy: technical aspects.
A system for high precision radiotherapy in the head and neck region has been developed. The components of the system are a head mask connected to a stereotactic frame, a localization unit that can be used during CT- and MR-imaging and a stereotactic target positioner. Conformal precision radiotherapy is planned with a new treatment planning system (Voxelplan-Heidelberg). Three different multi-leaf collimator systems are used. An evaluation of the precision and accuracy of the head fixation system, which was performed with a photogrammetry system, is presented.
Head↗
Fractionated stereotactically guided radiotherapy of head and neck tumors: a report on clinical use of a new system in 195 cases.
Between November 1988 and December 1992, 195 patients with tumors of the head and neck (low grade gliomas, meningiomas, neurinomas, chordomas and miscellaneous) were treated with a newly developed stereotactical system for fractionated, conformal, high-precision radiotherapy. The overall preparation time, including head mask production for fixation, CT, MRI, 3-D treatment planning and stereotactical localisation could be reduced to 4-5 h per patient. The use of MR in the target definition was increased to a mean of about 60%. The medial follow-up time is 22 months. Three different patient groups were selected according to pretreatment. Patients with full high-precision radiotherapy survived in 95% of cases, patients with boost treatment in 86% and patients with preirradiated recurrent disease in 64%. Meningiomas as the largest histology group (n = 62) showed partial response in 27% and complete response in 10% of cases. Progression occurred in two patients. All patients are alive. Acute side-effects were minimal and of the order of 10%, no late complications occurred despite tumor doses ranging up to 72 Gy. High-precision radiotherapy as it is performed in Heidelberg can be regarded as an effective, reliable and tolerable system for selected tumors of the head and neck.
Adolescent↗
[The value of radiotherapy for liver metastases].
The role of palliative irradiation was analysed in 55 patients with liver metastases from colorectal (n = 35), breast (n = 10) and lung cancer (n = 10), treated between January 1982 and June 1992 with irradiation doses more than 10 Gy. In 47 patients irradiation alone was done. The great majority of patients were treated because of pain (n = 21) or cholestasis (n = 22). In 29 patients the disease involved not only the liver, but was disseminated. A mean dose of 23.8 Gy was delivered, with daily fractions of 1.5 (n = 30), 1.8 (n = 1) or 2 Gy (n = 16). Complete and near complete pain relief was obtained in six (28.6%) and nine (42.9%) patients. Normalized and near normalized values of bilirubin serum levels were obtained in five (22.7%) and seven (31.9%) patients. As well relief of pain as normalisation of cholestasis were significantly correlated with the irradiation doses applied. Median survival was 36.5 days for patients with lung cancer, 70.5 and 73 days for patients with breast and colorectal cancer. Irradiation doses given (10 to 18 Gy vs. 19 to 28 Gy vs. 29 to 48 Gy) and the status of disease (liver only vs. disseminated) were significantly correlated to prognosis (p = 0.00001, p = 0.0007). Patients of the high-dose group or patients with liver metastases alone revealed a median survival of 174 or 175 days. Since May 1991 simultaneous radio-chemotherapy, with the systemic application of leukovorine and 5-FU, was performed in eight patients with colorectal cancer. After performing a three-dimensional radiotherapy planning, which enclosed the whole liver inside the target volume, a mean dose of 29.4 Gy, with daily single fractions of 1.5 Gy was delivered. The follow-up, done with CT or NMR revealed in seven patients a progression free interval of three to 8.5 (5.5) months. After a median follow-up of 221 days the median survival was 333 days. In the treatment of patients with liver metastases a clear therapeutic selection has to be done according to valid prognostic criteria. In the majority of our patients with clinical symptoms, i.e. pain or cholestasis, irradiation alone was sufficient for palliation of these symptoms. Prognosis is limited because of the disseminated state of disease in 62% of the patients. In a group of patients, suffering from colorectal cancer with good prognostic criteria, the simultaneous application of radiotherapy and systemic chemotherapy was able to increase significantly the survival with minor toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)
Breast Neoplasms↗
Cure in a patient with multiple osseus metastases in non-small cell lung cancer: a case report.
PURPOSE: This case was reported to describe a case of cure in a 61-year old patient with squamous cell lung cancer and multiple extrathoracic metastasis. METHODS AND MATERIALS: A left upper lobectomy of lung for a squamous cell carcinoma was performed on a 61-year old man with curative intent. Four months later two osseus metastases were irradiated with Cobalt 60 up to 40 Gy. RESULTS: The two irradiated lesions showed continuously shrinkage as well as signs of recalcification. Eleven years later the patient shows clinically absolute well being and on CT there are no signs of recurrent disease of the lung or bone anymore. DISCUSSION: To our knowledge has nobody so far reported of a case of as squamous cell lung cancer which was operated and irradiated on thus resulting in cure. Further on the authors discuss that it might well be worthwhile to define subgroups in stage 4 non-small cell lung cancer (presence of extrathoracic metastases) which might benefit from a more aggressive treatment approach than pure palliation.
Bone Neoplasms↗
[Three-dimensional radiation planning. Studies on clinical integration].
The routine use of three-dimensional treatment planning was evaluated in a clinical project funded by the German Krebshilfe at the Radiological Department of the University of Heidelberg. 166 patients entered the prospective study within 14 months, 155 of them were treated according to the 3D-plans. More than 50% of the patients had thoracic tumors, followed by pelvic tumors. One medicine physicist and one specially trained technician performed the treatment planning. The target volumes were contoured in the CT slices at the planning computer by the responsible radiotherapists. A mean of 6.5 hours per patient was necessary for all planning procedures, however, this time consumption shows a trend toward less time of only four hours including about ten optimization steps. Meanwhile approximately 20 to 30% of all computer assisted planning are performed in 3D, corresponding to about one plan per day. The achieved time consumption is a clinically accepted quantity, that allows the introduction of 3D-planning into clinical routine.
Abdominal Neoplasms↗
Radiotherapy treatment planning of basal meningiomas: improved tumor localization by correlation of CT and MR imaging data.
A localization technique, based on three-dimensional CT and MR imaging data for precision radiotherapy of basal meningiomas, is presented. Indications for radiotherapy included unresected tumors, gross disease remaining despite surgery, and recurrences. The patient's head was fixed in a stereotactic localization system which is usable at the CT, MR and the linear accelerator installations. The geometrical distortion of MR imaging data was evaluated in three dimensions by phantom measurements. The geometrical distortion was "corrected" (reducing displacements to the size of a pixel) by calculations based on modelling the distortion as a fourth order two-dimensional polynomial. The target volume was defined in three-dimensional MR imaging data after application of 0.1 mmol/kg b.w. Gd-DTPA solution and transferred precisely from MR onto CT data to provide a map of the radiation attenuation coefficient for dose calculation. The superior soft tissue contrast of MR showed an excellent tumor delineation especially when the bony base of the skull obscured the target in CT images. Target volume, calculated dose distribution, and critical structures could be transferred between CT and MR imaging data and displayed as three-dimensional shaded structures for better assessment for matching of target volume and dose distribution. With the described planning system a more precise target definition of basal meningiomas was possible by integration of the superior tumor delineation in MR compared with CT.
Computer Graphics↗
Charged particle therapy to pediatric tumors of the retroperitoneal region: a possible indication.
Despite a very successful interdisciplinary therapy regimen for pediatric solid tumors dominated by surgery and chemotherapy, the role of radiotherapy might become again more important if new techniques will allow a better dose localization to the target volume combined with a better protection of the normal tissue. This characteristic is known for charged particle beams. In a field study based on German cooperative trials, the possibility of a charged particle radiotherapy to retroperitoneal tumors of childhood will be discussed regarding indications in risk groups and recurrences. Absolute patient numbers are estimated from the clinical experiences and the incidences of the diseases. A stepwise introduction of this new therapy modality is proposed.
Adolescent↗
Computer systems and mechanical tools for stereotactically guided conformation therapy with linear accelerators.
An integrated system for fractionated, stereotactically guided conformation radiotherapy has been developed. The system components are a stereotactic fixation system that can be used each treatment day, a localization, and positioning unit that can be used during x-ray computer tomography, magnetic resonance imaging, positron emission tomography, and radiographical examinations as well as for treatment. Conformal precision radiotherapy is planned with a new three-dimensional treatment planning system (Voxel-Plan-Heidelberg) which comprises, among others options, a three-dimensional image correlation procedure as well as routines for the calculation of coplanar and non-coplanar irradiations with irregularly shaped fields. Two different multi-leaf collimators have been designed for precision radiotherapy in the head and neck region. A manual multi-leaf collimator is used for irradiations with stationary beams or for moving beam treatments with invariable irregularly shaped fields. This collimator system is now being used for patient treatments. The design of a computer controlled multi-leaf collimator unit for multiple fixed field irradiation techniques is discussed. All system components are aimed at conforming dose distributions for fractionated radiotherapy treatments to the target to improve sparing of adjacent normal tissues, and at achieving a sufficient geometrical accuracy in the dose application.
Computer Systems↗
[Aspergillosis of the central nervous system in glioblastoma multiforme].
A 45 year-old male with a butterfly glioma received stereotactic biopsy for histologic confirmation of the clinical diagnosis. Microscopically, the results were controversial since some biopsy specimens showed distinct inflammatory changes, while others displayed typical features of a malignant glioma. The patient died four days after the stereotactic approach due to therapy-resistant intracranial pressure rise. In addition to a large butterfly glioblastoma originating from the frontal part of the corpus callosum, neuropathologic examination revealed a mycotic encephalitis with formation of numerous fungi-containing inflammatory foci in all parts of the brain and in the glioma. General autopsy disclosed pulmonary aspergillosis as the source of the inflammatory spread. A previous steroid medication over several weeks for treatment of increased intracranial pressure may be considered as an important factor in the origin of the pulmonary aspergillosis complicating the butterfly glioma.
Aspergillosis↗
[Results of functional activator treatment of collum fractures in the growth period].
29 children aged between 2 and 16 and suffering from fractures of the condylar process were treated by functional appliances, 15 of them received previous intermaxillary wiring. Clinical and radiological reexamination including nuclear magnetic resonance tomography of the TMJ revealed good results for the use of functional appliances without previous immobilization.
Activator Appliances↗
[Fast response of an olfactory meningioma to radiotherapy].
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Brain Neoplasms↗
The medical heavy ion therapy project at the Gesellschaft für Schwerionenforschung facility in Darmstadt.
It could be demonstrated that local tumor control is considerably improved by radiation therapy with charged particles (protons or heavier ions). The advantages of heavy ion therapy compared to conventional photon therapy techniques are due to the better physical dose distributions achievable and the radiobiological characteristics of heavy ions. However, because of the expense and complexity of heavy ion therapy it is only carried out at a few facilities throughout the world. The Radiologische Universitätsklinik (Radiological University Hospital) and the Deutsches Krebsforschungszentrum (German Cancer Research Centre, DKFZ) in Heidelberg, in collaboration with the Gesellschaft für Schwerionenforschung (Laboratory for Heavy Ion, GSI) in Darmstadt, have developed a concept to use the new heavy ion synchrotron (Schwerionen-Synchroton SIS) in Darmstadt for medical-clinical irradiations. Due to the high flexibility of the SIS accelerator the medical program can be performed in addition to the planned physical experiments with minor interference only. The close geographical proximity of the three institutes involved and the accelerator which will be completed by the end of 1989 provide the unique opportunity to carry out relevant clinical, medical-physical, physical-technical, and radiobiological research in a relatively short time and, compared to similar projects in other countries, at low cost.
Costs and Cost Analysis↗
[Detection and assessment of cervical lymph node metastases in head-neck tumors. A comparison of methods].
From 1984 to 1987, seventy-two patients with squamous cell carcinomas involving oropharynx, hypopharynx, larynx and cervical lymph nodes, who underwent surgery, were examined to determine the value of computed tomography (CT), magnetic resonance (MR), high-resolution real-time sonography (US) and palpation in preoperative staging of cervical nodal metastases. The clinical staging was compared with the microscopic findings in the neck specimens and with operative reports. For the identification and description of cervical lymph node metastases, US and CT are more valuable than MR and palpation. In comparison to CT, however, US has advantages in most cervical areas as a dynamic method with variable representation of interesting regions. False positive errors are related to confusion with inflammatory nodes in all examinations. Metastatic infiltration of surrounding tissue especially of neck vessels, are best recognised by means of US and MR. However, the high rates of sensitivity and low rates of specificity of all methods point to the possibility of a great number of false positive errors in demonstrating tissue infiltration.
Angiography↗
[Detection of muscle, vein and artery infiltrations of cervical lymphatic metastases].
In a prospective study, 15 patients with squamous cell carcinomas of head and neck and clinical fixed cervical lymph node metastases were examined to determine the value of computed tomography, magnetic resonance imaging and high resolution real time ultrasonography in preoperative recognition of muscle and vessel infiltration. The preoperative findings were compared with the microscopic results of neck specimens and the operative reports. For each diagnostic method sensitivity, specificity, and effectivity were calculated. Ultrasonography, magnetic resonance imaging and computed tomography can assess muscle infiltrations as well. Metastatic infiltrations of carotid arteries are best recognised by ultrasonography and magnetic resonance imaging. Both methods are more valuable than computed tomography. All methods are unsuccessful in detecting infiltrations of the jugular vein. In conclusion, metastatic infiltrations of surrounding tissue, as described by imaging methods, are rarely confirmed by histological results.
Carcinoma, Squamous Cell↗
[Non-invasive follow-up control of tumor therapy following chemotherapy using 31P-MR spectroscopy in whole body tomography].
The 31P Magnetic Resonance Spectroscopy allows to monitor noninvasively and in vivo the energy and phospholipid metabolism of tissue. At present the high technical demand prevents the application of this new modality in the clinical routine. By means of some cases the advantages and limitations of the 31P-MRS are demonstrated. Recent results show that 31P-MRS monitors effects on the metabolism of tumor cells as early as two days after onset of chemotherapy. Further clinical studies and technical developments are necessary to render 31P-MRS a clinic routine examination.
Computer Graphics↗