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  1. Article ; Online: Die MIRAGE-Studie (MR-Linac-basierte Körperstereotaxie bei Prostatakarzinomen) – Precision at its best?

    Ehret, Felix

    Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al

    2024  Volume 200, Issue 3, Page(s) 255–258

    Title translation The MIRAGE Trial (MRI-guided stereotactic body radiotherapy for prostate cancer) - Precision at its best?
    MeSH term(s) Male ; Humans ; Radiosurgery ; Prostatic Neoplasms/radiotherapy ; Prostatic Neoplasms/surgery ; Radiotherapy, Image-Guided ; Magnetic Resonance Imaging
    Language German
    Publishing date 2024-01-05
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 84983-2
    ISSN 1439-099X ; 0179-7158 ; 0039-2073
    ISSN (online) 1439-099X
    ISSN 0179-7158 ; 0039-2073
    DOI 10.1007/s00066-023-02194-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online ; Thesis: Innovative Anwendungsmöglichkeiten der Hochpräzisionsbestrahlung

    Ehret, Felix [Verfasser]

    2023  

    Author's details Felix Ehret
    Keywords Medizin, Gesundheit ; Medicine, Health
    Subject code sg610
    Language German
    Publisher Medizinische Fakultät Charité - Universitätsmedizin Berlin
    Publishing place Berlin
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

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  3. Article ; Online: Protons or Photons - Let's Get It Done.

    Ehret, Felix / Shih, Helen A

    International journal of radiation oncology, biology, physics

    2023  Volume 115, Issue 3, Page(s) 555

    MeSH term(s) Humans ; Protons ; Photons/therapeutic use
    Chemical Substances Protons
    Language English
    Publishing date 2023-02-01
    Publishing country United States
    Document type Letter ; Comment
    ZDB-ID 197614-x
    ISSN 1879-355X ; 0360-3016
    ISSN (online) 1879-355X
    ISSN 0360-3016
    DOI 10.1016/j.ijrobp.2022.08.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Self-Shielding Gyroscopic Radiosurgery: A Prospective Experience and Analysis of the First 100 Patients.

    Ehret, Felix / Kohlhase, Nadja / Eftimova, Dochka / Hofmann, Theresa / Fürweger, Christoph / Haidenberger, Alfred / Kufeld, Markus / Muacevic, Alexander / Santacroce, Antonio

    Cureus

    2024  Volume 16, Issue 3, Page(s) e56035

    Abstract: Background Stereotactic radiosurgery is a well-established treatment option for the management of various benign and malignant brain tumors. It can be delivered with several treatment platforms, usually requiring shielded radiation vaults to meet ... ...

    Abstract Background Stereotactic radiosurgery is a well-established treatment option for the management of various benign and malignant brain tumors. It can be delivered with several treatment platforms, usually requiring shielded radiation vaults to meet regulatory safety requirements. Recent technical advances have led to the first self-shielding platform enabling the delivery of gyroscopic radiosurgery (GRS). Given the limited number of GRS treatment platforms, the novelty of its characteristics, and the lack of available data, we report our prospective experience with the first 100 patients treated with GRS. Materials and methods Patients undergoing GRS for the treatment of intracranial tumors were enrolled in this prospective study. Patient and treatment characteristics, including patient satisfaction, were collected and analyzed. Results A total of 100 patients with 155 tumors were treated. The most commonly treated tumors comprised brain metastases (BM) (49%), vestibular schwannomas (31%), and meningiomas (14%). The median prescription dose for malignant and benign tumors was 20 and 13 Gy, respectively. The median prescription isodose line was 56%. Gross tumor volumes were small, with a median of 0.37 cc for BM and 0.92 cc for the other entities. The median total treatment time was 40 minutes. Dosimetric performance indices showed median values of 1.20 (conformity index), 1.24 (new conformity index), 1.74 (homogeneity index), and 3.13 (gradient index). Volumetric assessment of the treated tumors showed an overall decrease in size at the first available follow-up. Most patients were satisfied with the treatment experience. Conclusion Our first prospective experience of the use of GRS is favorable. Analyses of the dosimetric performance, treatment times, volumetric assessment, and patient satisfaction demonstrate its suitability for stereotactic treatments of intracranial tumors. Further prospective clinical and dosimetric analyses for GRS are pending.
    Language English
    Publishing date 2024-03-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2747273-5
    ISSN 2168-8184
    ISSN 2168-8184
    DOI 10.7759/cureus.56035
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Applications of Frameless Image-Guided Robotic Stereotactic Radiotherapy and Radiosurgery in Pediatric Neuro-Oncology: A Systematic Review.

    Ehret, Felix / Kaul, David / Budach, Volker / Lohkamp, Laura-Nanna

    Cancers

    2022  Volume 14, Issue 4

    Abstract: Background: CyberKnife-based robotic radiosurgery (RRS) is a widely used treatment modality for various benign and malignant tumors of the central nervous system (CNS) in adults due to its high precision, favorable safety profile, and efficacy. Although ...

    Abstract Background: CyberKnife-based robotic radiosurgery (RRS) is a widely used treatment modality for various benign and malignant tumors of the central nervous system (CNS) in adults due to its high precision, favorable safety profile, and efficacy. Although RRS is emerging in pediatric neuro-oncology, scientific evidence for treatment indications, treatment parameters, and patient outcomes is scarce. This systematic review summarizes the current experience and evidence for RRS and robotic stereotactic radiotherapy (RSRT) in pediatric neuro-oncology.
    Methods: We performed a systematic review based on the databases Ovid Medline, Embase, Cochrane Library, and PubMed to identify studies and published articles reporting on RRS and RSRT treatments in pediatric neuro-oncology. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied herein. Articles were included if they described the application of RRS and RSRT in pediatric neuro-oncological patients. The quality of the articles was assessed based on their evidence level and their risk for bias using the original as well as an adapted version of the Newcastle Ottawa Quality Assessment Scale (NOS). Only articles published until 1 August 2021, were included.
    Results: A total of 23 articles were included after final review and removal of duplicates. Articles reported on a broad variety of CNS entities with various treatment indications. A majority of publications lacked substantial sample sizes and a prospective study design. Several reports included adult patients, thereby limiting the possibility of data extraction and analysis of pediatric patients. RRS and RSRT were mostly used in the setting of adjuvant, palliative, and salvage treatments with decent local control rates and acceptable short-to-intermediate-term toxicity. However, follow-up durations were limited. The evidence level was IV for all studies; the NOS score ranged between four and six, while the overall risk of bias was moderate to low.
    Conclusion: Publications on RRS and RSRT and their application in pediatric neuro-oncology are rare and lack high-quality evidence with respect to entity-related treatment standards and long-term outcomes. The limited data suggest that RRS and RSRT could be efficient treatment modalities, especially for children who are unsuitable for surgical interventions, suffer from tumor recurrences, or require palliative treatments. Nevertheless, the potential short-term and long-term adverse events must be kept in mind when choosing such a treatment. Prospective studies are necessary to determine the actual utility of RRS and RSRT in pediatric neuro-oncology.
    Language English
    Publishing date 2022-02-21
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2527080-1
    ISSN 2072-6694
    ISSN 2072-6694
    DOI 10.3390/cancers14041085
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Robotic CyberKnife Radiosurgery for the Treatment of Choroidal and Ciliary Body Melanoma.

    Liegl, Raffael / Schmelter, Valerie / Fuerweger, Christoph / Ehret, Felix / Priglinger, Siegfried / Muacevic, Alexander / Foerster, Paul

    American journal of ophthalmology

    2023  Volume 250, Page(s) 177–185

    Abstract: Purpose: To present the results of robotic-assisted radiosurgery in choroidal and ciliary body melanomas treated at the Department of Ophthalmology of Ludwig-Maximilians-University and the European CyberKnife Center in Munich, Germany.: Design: ... ...

    Abstract Purpose: To present the results of robotic-assisted radiosurgery in choroidal and ciliary body melanomas treated at the Department of Ophthalmology of Ludwig-Maximilians-University and the European CyberKnife Center in Munich, Germany.
    Design: Interventional case series METHODS: This retrospective study included 594 consecutive patients referred to our clinic for the treatment of choroidal and ciliary body melanomas with robotic radiosurgery (CyberKnife) from 2005 to 2019. Eye retention, local control and disease-specific survival rates were calculated as Kaplan-Meier and actuarial estimates. The impact of prescription dose, tumor size, and ciliary body involvement was assessed by likelihood ratio tests and Cox regression.
    Results: Among all patients who were staged according to the TNM classification system (8th edition), 22.7% were I, 57.9% were II, 18.9% were III, and 0.5% were IV. Median apical tumor height and base diameter were 5.8 and 11.4 mm. The mean follow-up was 41.7 months. Local control after 3 and 5 years was 92.0% (95% CI = 88.2%-94.7%) and 84.3% (95% CI = 77.9%-89.0%), respectively, for 21 to 22 Gy and 86.9% (95% CI = 79.7%-91.7%) and 77.7% (95% CI = 68.5%-84.6%), respectively, when treated with 20 Gy or less. Eye retention was achieved in 89.9% and 81.0% after 3 and 5 years with 21 to 22 Gy and 85.9% and 80.0% for 20 Gy or less. Disease-specific survival rates were 93.1% (95% CI = 90.2%-95.2%) after 3 years, 89.8% (95% CI = 86.0%-92.6%) after 5 years, and 87.8% (95% CI = 82.8%-91.4%) after 7 years.
    Conclusions: This is the largest series of patients treated for choroidal and ciliary body melanomas with CyberKnife. Our results reflect an improvement in the outcome of CyberKnife therapy for patients with choroidal and ciliary body melanoma treated with single-session radiosurgery in the last decade.
    MeSH term(s) Humans ; Radiosurgery/adverse effects ; Radiosurgery/methods ; Robotic Surgical Procedures ; Ciliary Body/surgery ; Retrospective Studies ; Melanoma/radiotherapy ; Melanoma/surgery ; Treatment Outcome
    Language English
    Publishing date 2023-01-13
    Publishing country United States
    Document type Journal Article
    ZDB-ID 80030-2
    ISSN 1879-1891 ; 0002-9394
    ISSN (online) 1879-1891
    ISSN 0002-9394
    DOI 10.1016/j.ajo.2022.12.021
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: A Suspected Vestibular Schwannoma with Uncharacteristic Growth Dynamic and Symptom Severity: A Case Report.

    Ehret, Felix / Muacevic, Alexander

    Cureus

    2018  Volume 10, Issue 1, Page(s) e2024

    Abstract: Vestibular schwannomas are mostly sporadic, neuroectodermal, benign tumors of the myelin-forming cells of the vestibulocochlear nerve. Typical initial symptoms of vestibular schwannomas often include unilateral hearing loss, tinnitus, vertigo, and ... ...

    Abstract Vestibular schwannomas are mostly sporadic, neuroectodermal, benign tumors of the myelin-forming cells of the vestibulocochlear nerve. Typical initial symptoms of vestibular schwannomas often include unilateral hearing loss, tinnitus, vertigo, and headaches. As schwannomas characteristically show a slow growth rate and various symptoms, different therapeutic approaches are possible, ranging from a watchful waiting strategy to radiation therapy and neurosurgical tumor removal. In addition, these treatment options should be evaluated carefully and assigned individually to the patients' needs and symptoms while respecting the feasibility and possible outcome of the chosen treatment. We present a 69-year-old patient with an atypical, severe symptom constellation and tumor growth dynamic. The planned treatment of the schwannoma with radiosurgery revealed an unforeseen change of focus. Most notably, this case emphasizes the importance of a thorough radiological and patient-orientated assessment.
    Language English
    Publishing date 2018-01-05
    Publishing country United States
    Document type Case Reports
    ZDB-ID 2747273-5
    ISSN 2168-8184
    ISSN 2168-8184
    DOI 10.7759/cureus.2024
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Single-fraction prostate-specific membrane antigen positron emission tomography- and multiparametric magnetic resonance imaging-guided stereotactic body radiotherapy for prostate cancer local recurrences.

    Ehret, Felix / Hofmann, Theresa / Fürweger, Christoph / Kufeld, Markus / Staehler, Michael / Muacevic, Alexander / Haidenberger, Alfred

    BJU international

    2022  Volume 131, Issue 1, Page(s) 101–108

    Abstract: Objective: To analyse the efficacy and safety of focal prostate-specific membrane antigen positron emission tomography (PSMA-PET)- and multiparametric magnetic resonance imaging (mpMRI)-guided single-fraction stereotactic body radiotherapy (SBRT) for ... ...

    Abstract Objective: To analyse the efficacy and safety of focal prostate-specific membrane antigen positron emission tomography (PSMA-PET)- and multiparametric magnetic resonance imaging (mpMRI)-guided single-fraction stereotactic body radiotherapy (SBRT) for the treatment of prostate cancer (PCa) local recurrences.
    Patients and methods: Patients with PSMA-PET-positive PCa local recurrences treated with single-fraction SBRT between 2016 and 2020 were included. Identification for subsequent recurrences or metastatic spread based on increasing prostate-specific antigen (PSA) levels were evaluated using PSMA-PET imaging.
    Results: A total of 64 patients were identified. Patients received various treatments before SBRT (31 patients with radical prostatectomy [RP], 18 external beam radiotherapy [EBRT] with RP, five EBRT, and the remaining 10 other combinations). The median follow-up was 21.6 months. The median PSA level before SBRT was 1.47 ng/mL. All patients received a single-fraction treatment with a median prescription dose and isodose line of 21 Gy and 65%, respectively. At the time of SBRT, six patients (9%) received an androgen deprivation therapy (ADT). PSA levels decreased after SBRT (P = 0.03) and three local recurrences were detected during the follow-up. The progression-free survival after 1-, 2-, and 3-years was 85.3%, 65.9%, and 51.2%, respectively. Six patients (9%) started ADT after SBRT due to disease progression. The rates of newly started ADT after 1-, 2-, and 3-years were 1.8%, 7.3%, and 22.7%, respectively. Grade 1 or 2 toxicities occurred in six patients (9%); no high-grade toxicity was observed.
    Conclusion: While the available data for SBRT in the PCa local recurrence setting describe outcomes for fractionated irradiations, the findings of this first analysis of single-fraction, PSMA-PET- and mpMRI-guided focal SBRT are encouraging. Such treatment appears to be a safe, efficient, and time-saving therapy even in intensively pretreated patients. Recurrence-directed treatments can delay the use of ADT and could avoid prostate bed irradiation in selected patients.
    MeSH term(s) Male ; Humans ; Prostatic Neoplasms/diagnostic imaging ; Prostatic Neoplasms/radiotherapy ; Prostatic Neoplasms/pathology ; Radiosurgery ; Prostate-Specific Antigen ; Multiparametric Magnetic Resonance Imaging ; Prostate/pathology ; Androgen Antagonists/therapeutic use ; Neoplasm Recurrence, Local/diagnostic imaging ; Neoplasm Recurrence, Local/radiotherapy ; Neoplasm Recurrence, Local/pathology ; Positron-Emission Tomography ; Positron Emission Tomography Computed Tomography/methods
    Chemical Substances Prostate-Specific Antigen (EC 3.4.21.77) ; Androgen Antagonists
    Language English
    Publishing date 2022-10-09
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1462191-5
    ISSN 1464-410X ; 1464-4096 ; 1358-8672
    ISSN (online) 1464-410X
    ISSN 1464-4096 ; 1358-8672
    DOI 10.1111/bju.15894
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Self-Shielding Gyroscopic Radiosurgery-A First Clinical Experience, Case Series, and Dosimetric Comparison.

    Muacevic, Alexander / Eder, Michael Martin / Hofmann, Theresa / Fürweger, Christoph / Ehret, Felix

    World neurosurgery

    2022  Volume 164, Page(s) e420–e426

    Abstract: Background: Self-shielding gyroscopic radiosurgery (GRS) represents a technical innovation in the field of stereotactic radiosurgery. GRS does not require a radiation vault and is optimized for radiosurgical treatments. Reports on its usage are limited. ...

    Abstract Background: Self-shielding gyroscopic radiosurgery (GRS) represents a technical innovation in the field of stereotactic radiosurgery. GRS does not require a radiation vault and is optimized for radiosurgical treatments. Reports on its usage are limited. We describe the first clinical experience of GRS at our institution to assess the application of GRS in the treatment of cranial tumors. Moreover, we perform a dosimetric comparison to robotic radiosurgery (RRS) with vestibular schwannoma (VS) GRS patients.
    Methods: Patients who were treated with GRS between July and November 2021 were included. Patient, tumor, and dosimetric characteristics were retrospectively summarized and analyzed.
    Results: Forty-one patients with 48 intracranial tumors were included. Tumor entities mostly comprised VS, brain metastases, and meningiomas. The median prescription dose and isodose line were 13.5 Gy and 50.0% for benign neoplasia versus 20 Gy and 60.0% for malignant tumors, respectively. The mean planning target volume was 1.5 cubic centimeters. All patients received a single-fraction treatment without encountering any technical setup difficulties. Treatment plan comparisons with RRS revealed comparable plan characteristics, dose gradients, and organs at risk doses. Significant differences were detected concerning the new conformity index and number of monitor units per treatment (both P < 0.01).
    Conclusions: This case series provides more evidence on the usage of self-shielding GRS in the management of cranial tumors. Dosimetric comparisons for VS cases revealed mostly equivalent dosimetric characteristics to RRS. Further clinical and physical analyses for GRS are underway.
    MeSH term(s) Brain Neoplasms/radiotherapy ; Brain Neoplasms/secondary ; Brain Neoplasms/surgery ; Humans ; Neuroma, Acoustic/radiotherapy ; Neuroma, Acoustic/surgery ; Radiometry ; Radiosurgery ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Retrospective Studies
    Language English
    Publishing date 2022-05-11
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2534351-8
    ISSN 1878-8769 ; 1878-8750
    ISSN (online) 1878-8769
    ISSN 1878-8750
    DOI 10.1016/j.wneu.2022.04.120
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Outcomes of Isocitrate Dehydrogenase Wild Type Glioblastoma after Re-irradiation.

    Ehret, Felix / Wolfgang, Josy / Allwohn, Luisa / Onken, Julia / Wasilewski, David / Roohani, Siyer / Oertel, Joachim / Zips, Daniel / Kaul, David

    Clinical and translational radiation oncology

    2023  Volume 42, Page(s) 100653

    Abstract: Purpose: Glioblastomas (GBM) are the most common malignant primary brain tumors in adults and have a dismal prognosis. Patients frequently suffer from local tumor recurrences, with limited therapeutic options. Re-irradiation represents a possible ... ...

    Abstract Purpose: Glioblastomas (GBM) are the most common malignant primary brain tumors in adults and have a dismal prognosis. Patients frequently suffer from local tumor recurrences, with limited therapeutic options. Re-irradiation represents a possible intervention, but given the recent 5th edition of the World Health Organization classification of central nervous system tumors, studies in isocitrate dehydrogenase wild type (IDH-wt) cohorts undergoing a second course of radiotherapy remain limited. Herein, we sought to describe our institutional experience and outcomes after GBM IDH-wt re-irradiation.
    Materials and methods: GBM patients with confirmed IDH-wt status undergoing re-irradiation were included in this single-center, retrospective analysis.
    Results: A total of 88 patients were analyzed. The median clinical and radiographic follow-up periods were 4.6 months and 4.4 months, respectively. Most patients had a Karnofsky performance status of at least 80% (n = 57). The median biologically effective dose and 2 Gy equivalent dose (EQD2) for re-irradiations, assuming an α/β ratio of 10 Gy for GBM, were 51.4 and 42.8 Gy, respectively. In total, 71 deaths were recorded. The median overall survival (OS) was 8.0 months. Multivariable Cox regression of OS revealed a positive influence of gross total resection vs. biopsy or no resection (hazard ratio: 0.43, p = 0.02). The median progression-free survival (PFS) was 5.9 months. The multivariable Cox regression for PFS did not detect any significant factors. No clear evidence of radiation necrosis was recorded during the available follow-up. However, only a minority (n = 4) of patients underwent surgery after re-irradiation, none showing histopathological proof of radiation necrosis.
    Conclusion: The prognosis for recurrent IDH-wt GBM after re-irradiation is poor. Patients who are amenable and able to undergo re-resection may have a favorable OS. A second course of radiotherapy with a moderate cumulative EQD2 and small- to medium-sized planning target volumes appeared safe regarding the occurrence of radiation necrosis.
    Language English
    Publishing date 2023-06-13
    Publishing country Ireland
    Document type Journal Article
    ISSN 2405-6308
    ISSN (online) 2405-6308
    DOI 10.1016/j.ctro.2023.100653
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