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  • ONCOLOGY  (12)
  • NUCLEAR-MEDICINE  (11)
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  • 1
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    Springer Verlag
    Keywords: radiation ; OPTIMIZATION ; treatment ; TECHNOLOGY ; inverse planning ; ONCOLOGY ; RADIATION ONCOLOGY
    Type of Publication: Book chapter
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  • 2
    Keywords: OPTIMIZATION ; radiotherapy ; Germany ; THERAPY ; ALGORITHM ; ALGORITHMS ; imaging ; NUCLEAR-MEDICINE ; radiation ; SEQUENCE ; treatment ; DISTRIBUTIONS ; RADIATION-THERAPY ; DIFFERENCE ; NUMBER ; BEAM ; DELIVERY ; STRATEGIES ; INTENSITY-MODULATED RADIOTHERAPY ; MULTILEAF COLLIMATOR ; SEGMENTS ; nuclear medicine ; IMRT ; APPROXIMATION ; MAPS ; radiology ; PROGRAM ; THERAPIES ; radiation therapy ; intensity modulated radiotherapy ; NUCLEAR ; technique ; BEAMS ; MEDICINE ; ERROR ; CONSTRAINTS
    Abstract: In inverse planning for intensity-modulated radiotherapy ( IMRT), the fluence distribution of each treatment beam is usually calculated in an optimization process. The delivery of the resulting treatment plan using multileaf collimators ( MLCs) is performed either in the step-and-shoot or sliding window technique. For step-and-shoot delivery, the arbitrary beam fluence distributions have to be transformed into an applicable sequence of subsegments. In a stratification step the complexity of the fluence maps is reduced by assigning each beamlet to discrete intensity values, followed by the sequencing step that generates the subsegments. In this work, we concentrate on the stratification for step-and-shoot delivery. Different concepts of stratification are formally introduced. In addition to already used strategies that minimize the difference between original and stratified beam intensities, we propose an original stratification principle that minimizes the error of the resulting dose distribution. It could be shown that for a comparable total number of subsegments the dose-oriented stratification results in a better approximation of the original, unsequenced plan. The presented algorithm can replace the stratification routine in existing sequencer programs and can also be applied to interpolated plans that are generated in an interactive decision making process of multicriteria inverse planning programs
    Type of Publication: Journal article published
    PubMed ID: 17881818
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  • 3
    Keywords: tumor ; COMBINATION ; evaluation ; Germany ; THERAPY ; CT ; FOLLOW-UP ; imaging ; VOLUME ; DISEASE ; NEW-YORK ; validation ; NUCLEAR-MEDICINE ; PATIENT ; MRI ; SEQUENCE ; SEQUENCES ; chemotherapy ; VARIABILITY ; FUNCTION TESTS ; MOTION ; nuclear medicine ; mesothelioma ; PLEURAL MESOTHELIOMA ; dynamic MRI ; radiology ; malignant pleural mesothelioma ; THERAPIES ; IMAGING TECHNIQUES ; WEIGHT ; breathing cycle ; NUCLEAR ; CRITERIA ; technique ; USA ; correlation ; MEDICINE ; comparison ; KAPPA ; VALUES ; INTEROBSERVER ; RECIST ; RECIST CRITERIA ; MPM ; tumour volumetry
    Abstract: To evaluate and compare early therapy response according to RECIST (response evaluation criteria in solid tumours) and modified RECIST criteria using MRI techniques in patients with malignant pleural mesothelioma (MPM) in comparison with CT. Fifty patients with MPM (32 male/18 female) were included in this study. Early therapy response was evaluated after 9 weeks [three of six chemotherapy (CHT)] cycles. Additionally patients were examined before chemotherapy, 4 weeks after early therapy response evaluation and after six cycles to evaluate diagnostic follow-up. RECIST and modified RECIST criteria were applied using CT and MRI (HASTE, VIBE, T2-TSE sequences). In MRI additionally a volumetric approach measuring tumour weight (overall segmented tumour volume) was applied. Additionally vital capacity (VC) was measured for correlation. Image interpretation was performed by three independent readers independently and in consensus. The 'gold standard' was follow-up examination. Twenty-eight patients showed partial response, 12 patients stable disease and 10 patients progressive disease at early therapy response evaluation. In the follow-up these results remained. For MRI, in 46 cases patients were identically classified using RECIST and modified RECIST criteria. Modified RECIST criteria were identically classified as gold standards in all cases, whereas using RECIST criteria in four cases there was a mismatch (partial response vs. stable disease). Modified RECIST kappa values showed better interobserver variability compared with RECIST criteria (kappa=0.9-1.0 vs. 0.7-1.0). For CT, in 44 cases patients were identically classified using RECIST and modified RECIST criteria. Modified RECIST criteria were identically classified as in gold standards in 48 out of 50 patients, whereas using RECIST criteria in 6 cases there was a mismatch (partial response vs. stable disease). Modified RECIST kappa values showed better interobserver variability compared with RECIST criteria (kappa=0.9-1.0 vs. 0.6-1.0). Modified RECIST criteria especially in combination with high-resolution MRI is a very accurate and reproducible technique to correctly evaluate early therapy response in MPM
    Type of Publication: Journal article published
    PubMed ID: 18369634
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  • 4
    Keywords: CELLS ; radiotherapy ; SURVIVAL ; tumor ; CELL ; Germany ; neoplasms ; THERAPY ; TOXICITY ; FOLLOW-UP ; DISEASE ; TUMORS ; SURGERY ; radiation ; MRI ; PROGRESSION ; CONFORMAL RADIOTHERAPY ; EXPERIENCE ; RADIATION-THERAPY ; AGE ; EFFICACY ; REGION ; HEAD ; NECK ; local control ; ONCOLOGY ; overall survival ; radiation therapy ; MENINGIOMAS ; BONE ; SCAN ; INSTITUTION ; CASE SERIES
    Abstract: Background: Giant cell tumors are rare neoplasms, representing less than 5% of all bone tumors. The vast majority of giant cell tumors occurs in extremity sites and is treated by surgery alone. However, a small percentage occurs in pelvis, spine or skull bones, where complete resection is challenging. Radiation therapy seems to be an option in these patients, despite the lack of a generally accepted dose or fractionation concept. Here we present a series of five cases treated with high dose IMRT. Patients and Methods: From 2000 and 2006 a total of five patients with histologically proven benign giant cell tumors have been treated with IMRT in our institution. Two patients were male, three female, and median age was 30 years (range 20 - 60). The tumor was located in the sacral region in four and in the sphenoid sinus in one patient. All patients had measurable gross disease prior to radiotherapy with a median size of 9 cm. All patients were treated with IMRT to a median total dose of 64 Gy (range 57.6 Gy to 66 Gy) in conventional fractionation. Results: Median follow up was 46 months ranging from 30 to 107 months. Overall survival was 100%. One patient developed local disease progression three months after radiotherapy and needed extensive surgical salvage. The remaining four patients have been locally controlled, resulting in a local control rate of 80%. We found no substantial tumor shrinkage after radiotherapy but in two patients morphological signs of extensive tumor necrosis were present on MRI scans. Decline of pain and/or neurological symptoms were seen in all four locally controlled patients. The patient who needed surgical salvage showed markedly reduced pain but developed functional deficits of bladder, rectum and lower extremity due to surgery. No severe acute or late toxicities attributable to radiation therapy were observed so far. Conclusion: IMRT is a feasible option in giant cells tumors not amendable to complete surgical removal. In our case series local control was achieved in four out of five patients with marked symptom relief in the majority of cases. No severe toxicity was observed
    Type of Publication: Journal article published
    PubMed ID: 20187955
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  • 5
    Keywords: OPTIMIZATION ; radiotherapy ; evaluation ; Germany ; human ; PROSTATE ; ALGORITHM ; imaging ; SYSTEM ; VISUALIZATION ; meningioma ; NUCLEAR-MEDICINE ; TIME ; PATIENT ; QUALITY ; REDUCTION ; treatment ; FORM ; ELEMENT ; NO ; TRIAL ; RADIATION-THERAPY ; DATABASE ; BEAM ; INTENSITY-MODULATED RADIOTHERAPY ; sensitivity ; nuclear medicine ; IMRT ; radiology ; ONCOLOGY ; PROGRAM ; sensitivity analysis ; RE ; REAL-TIME ; interaction ; intensity modulated radiotherapy ; analysis ; methods ; NUCLEAR ; navigation ; BRACHYTHERAPY ; MEDICINE ; NOV ; user interface ; ERROR ; clinical evaluation ; DOSE OPTIMIZATION ; interactive ; inverse planning system ; multiobjective ; mutticriteria
    Abstract: Background and purpose: Currently, inverse planning for intensity-modulated radiotherapy (IMRT) can be a timeconsuming trial and error process. This is because many planning objectives are inherently contradictory and cannot reach their individual optimum all at the same time. Therefore in clinical practice the potential of IMRT cannot be fully exploited for all patients. Multicriteria (multiobjective) optimization combined with interactive plan navigation is a promising approach to overcome these problems. Patients and methods: We developed a new inverse planning system called "Multicriteria Interactive Radiotherapy Assistant (MIRA)". The optimization result is a database of patient specific, Pareto-optimal plan proposals. The database is explored with an intuitive user interface that utilizes both a new interactive element for plan navigation and familiar dose visualizations in form of DVH and isoclose projections. Two clinical test cases, one paraspinal meningioma case and one prostate case, were optimized using MIRA and compared with the clinically approved planning program KonRad. Results: Generating the databases required no user interaction and took approx. 2-3 h per case. The interactive exploration required only a few minutes until the best plan was identified, resulting in a significant reduction of human planning time. The achievable plan quality was comparable to KonRad with the additional benefit of having plan alternatives at hand to perform a sensitivity analysis or to decide for a different clinical compromise. Conclusions: The MIRA system provides a complete database and interactive exploration of the solution space in real time. Hence, it is ideally suited for the inherently multicriterial problem of inverse IMRT treatment planning. (c) 2007 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 17892901
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  • 6
    Keywords: OPTIMIZATION ; Germany ; imaging ; VISUALIZATION ; NUCLEAR-MEDICINE ; TIME ; MOUSE ; IDENTIFICATION ; RADIATION-THERAPY ; INTENSITY-MODULATED RADIOTHERAPY ; treatment planning ; SELECTION ; nuclear medicine ; IMRT ; radiology ; INCREASE ; methods ; NUCLEAR ; ENGLAND ; navigation ; EXCLUSION ; INCREASES ; MEDICINE ; VALUES ; interactions ; OPERATIONS ; interactive ; EFFICIENT SET
    Abstract: Inherently, IMRT treatment planning involves compromising between different planning goals. Multi- criteria IMRT planning directly addresses this compromising and thus makes it more systematic. Usually, several plans are computed from which the planner selects the most promising following a certain procedure. Applying Pareto navigation for this selection step simultaneously increases the variety of planning options and eases the identification of the most promising plan. Pareto navigation is an interactive multi- criteria optimizationmethod that consists of the two navigationmechanisms 'selection' and 'restriction'. The former allows the formulation of wishes whereas the latter allows the exclusion of unwanted plans. They are realized as optimization problems on the so- called plan bundle - a set constructed from pre- computed plans. They can be approximately reformulated so that their solution time is a small fraction of a second. Thus, the user can be provided with immediate feedback regarding his or her decisions. Pareto navigation was implemented in the MIRA navigator software and allows real- time manipulation of the current plan and the set of considered plans. The changes are triggered by simple mouse operations on the so- called navigation star and lead to real- time updates of the navigation star and the dose visualizations. Since any Pareto- optimal plan in the plan bundle can be found with just a few navigation operations the MIRA navigator allows a fast and directed plan determination. Besides, the concept allows for a refinement of the plan bundle, thus offering a middle course between single plan computation and multi- criteria optimization. Pareto navigation offers so far unmatched real- time interactions, ease of use and plan variety, setting it apart from the multi- criteria IMRT planning methods proposed so far
    Type of Publication: Journal article published
    PubMed ID: 18263953
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  • 7
    Keywords: radiotherapy ; Germany ; LUNG ; imaging ; LUNG-CANCER ; RISK ; TISSUE ; NUCLEAR-MEDICINE ; radiation ; PATIENT ; INDEX ; TARGET ; chemotherapy ; NORMAL TISSUE ; nuclear medicine ; mesothelioma ; PLEURAL MESOTHELIOMA ; IMRT ; FEASIBILITY ; MANAGEMENT ; NECK-CANCER ; radiology ; ONCOLOGY ; methods ; NUCLEAR ; MODULATED RADIATION-THERAPY ; MEDICINE ; comparison ; PENCIL BEAM ; TOMOTHERAPY ; TREATMENT PLANS ; MPM ; helical tomotherapy ; EXTRAPLEURAL PNEUMONECTOMY ; HEIDELBERG EXPERIENCE ; HEMITHORACIC RADIATION ; step-and-shoot IMRT
    Abstract: Purpose: To evaluate the potential of helical tomotherapy in the adjuvant treatment of malignant pleural mesothelionna and compare target homogeneity, conformity and normal tissue dose with step-and-shoot intensity-modulated radiotherapy. Methods and materials: Ten patients with malignant pleural mesothelioma who had undergone neoadjuvant chemotherapy with cisplatin and permetrexed followed by extrapleural pneumonectomy (EPP) were treated in our department with 54 Gy to the hemithorax delivered by step-and-shoot IMRT. A planning comparison was performed by creating radiation plans for helical tomotherapy. The different plans were compared by analysing target homogeneity using the homogeneity indices HImax and HImin and target conformity by using the conformity index CI95. To assess target coverage and normal tissue sparing TV90, TV95 and mean and maximum doses were compared. Results: Both modalities achieved excellent dose distributions while sparing organs at risk. Target coverage and homogeneity could be increased significantly with helical tomotherapy compared with step-and-shoot IMRT. Mean dose to the contralateral lung could be lowered beyond 5 Gy. Conclusions: Our planning study showed that helical tomotherapy is an excellent option for the adjuvant intensity-modulated radiotherapy of MPM. It is capable of improving target coverage and homogeneity. (c) 2007 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 18207597
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  • 8
    Keywords: CANCER ; SURVIVAL ; Germany ; LUNG ; PROSTATE ; THERAPY ; lung cancer ; LUNG-CANCER ; DEATH ; DISEASE ; LONG-TERM ; MORTALITY ; POPULATION ; RISK ; HEART ; prognosis ; BREAST ; breast cancer ; BREAST-CANCER ; MALIGNANCIES ; AGE ; colorectal cancer ; COLORECTAL-CANCER ; COUNTRIES ; PROSTATE-CANCER ; LONG-TERM SURVIVAL ; CANCER-PATIENTS ; UNITED-STATES ; FAILURE ; TRENDS ; STROKE ; ONCOLOGY ; HEART-FAILURE ; COMPETING RISKS ; 1ST-EVER STROKE ; 5 CONTINENTS ; 5-YEAR SURVIVAL ; PERTH COMMUNITY STROKE ; PRESERVED EJECTION FRACTION
    Abstract: Background: Cancer, heart failure and stroke are among the most common causes of death worldwide. Investigation of the prognostic impact of each disease is important, especially for a better understanding of competing risks. Aim of this study is to provide an overview of long term survival of cancer, heart failure and stroke patients based on the results of large population- and hospital-based studies. Methods: Records for our study were identified by searches of Medline via Pubmed. We focused on observed and relative age- and sex-adjusted 5-year survival rates for cancer in general and for the four most common malignancies in developed countries, i.e. lung, breast, prostate and colorectal cancer, as well as for heart failure and stroke. Results: Twenty studies were identified and included for analysis. Five-year observed survival was about 43% for all cancer entities, 40-68% for stroke and 26-52% for heart failure. Five-year age and sex adjusted relative survival was 50-57% for all cancer entities, about 50% for stroke and about 62% for heart failure. In regard to the four most common malignancies in developed countries 5-year relative survival was 12-18% for lung cancer, 73-89% for breast cancer, 50-99% for prostate cancer and about 43-63% for colorectal cancer. Trend analysis revealed a survival improvement over the last decades. Conclusions: The results indicate that long term survival and prognosis of cancer is not necessarily worse than that of heart failure and stroke. However, a comparison of the prognostic impact of the different diseases is limited, corroborating the necessity for further systematic investigation of competing risks
    Type of Publication: Journal article published
    PubMed ID: 20307299
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  • 9
    Keywords: ONCOLOGY ; radiology ; IMRT ; nuclear medicine ; imaging ; SYSTEM ; NEW-YORK ; NUCLEAR-MEDICINE ; PROSTATE ; interactive ; MEDICINE ; USA ; NUCLEAR
    Type of Publication: Meeting abstract published
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  • 10
    Keywords: Germany ; PROSTATE ; NUCLEAR-MEDICINE ; imaging ; nuclear medicine ; MOTION ; ONCOLOGY ; radiology ; analysis ; NUCLEAR ; MEDICINE
    Type of Publication: Meeting abstract published
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