@article{LisowskiLutyjAbazarietal.2023,
  author    = {Lisowski, Dominik and Lutyj, Paul and Abazari, Arya and Weick, Stefan and Traub, Jan and Polat, B{\"u}lent and Flentje, Michael and Kraft, Johannes},
  title     = {Impact of Radiotherapy on Malfunctions and Battery Life of Cardiac Implantable Electronic Devices in Cancer Patients},
  series = {Cancers},
  volume    = {15},
  journal   = {Cancers},
  number    = {19},
  issn      = {2072-6694},
  doi       = {10.3390/cancers15194830},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-358008},
  year      = {2023},
  abstract  = {Purpose: This study analyses a large number of cancer patients with CIEDs for device malfunction and premature battery depletion by device interrogation after each radiotherapy fraction and compares different guidelines in regard to patient safety. Methods: From 2007 to 2022, a cohort of 255 patients was analyzed for CIED malfunctions via immediate device interrogation after every RT fraction. Results: Out of 324 series of radiotherapy treatments, with a total number of 5742 CIED interrogations, nine device malfunctions (2.8\%) occurred. Switching into back-up/safety mode and software errors occurred four times each. Once, automatic read-out could not be performed. The median prescribed cumulative dose at planning target volume (PTV) associated with CIED malfunction was 45.0 Gy (IQR 36.0-64.0 Gy), with a median dose per fraction of 2.31 Gy (IQR 2.0-3.0 Gy). The median maximum dose at the CIED at time of malfunction was 0.3 Gy (IQR 0.0-1.3 Gy). No correlation between CIED malfunction and maximum photon energy (p = 0.07), maximum dose at the CIED (p = 0.59) nor treatment localization (p = 0.41) could be detected. After excluding the nine malfunctions, premature battery depletion was only observed three times (1.2\%). Depending on the national guidelines, 1-9 CIED malfunctions in this study would have been detected on the day of occurrence and in none of the cases would patient safety have been compromised. Conclusion: Radiation-induced malfunctions of CIEDs and premature battery depletion are rare. If recommendations of national safety guidelines are followed, only a portion of the malfunctions would be detected directly after occurrence. Nevertheless, patient safety would not be compromised.},
  language  = {en}
}
@article{HuflageKunzHendeletal.2023,
  author    = {Huflage, Henner and Kunz, Andreas Steven and Hendel, Robin and Kraft, Johannes and Weick, Stefan and Razinskas, Gary and Sauer, Stephanie Tina and Pennig, Lenhard and Bley, Thorsten Alexander and Grunz, Jan-Peter},
  title     = {Obesity-related pitfalls of virtual versus true non-contrast imaging — an intraindividual comparison in 253 oncologic patients},
  series = {Diagnostics},
  volume    = {13},
  journal   = {Diagnostics},
  number    = {9},
  issn      = {2075-4418},
  doi       = {10.3390/diagnostics13091558},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313519},
  year      = {2023},
  abstract  = {Objectives: Dual-source dual-energy CT (DECT) facilitates reconstruction of virtual non-contrast images from contrast-enhanced scans within a limited field of view. This study evaluates the replacement of true non-contrast acquisition with virtual non-contrast reconstructions and investigates the limitations of dual-source DECT in obese patients. Materials and Methods: A total of 253 oncologic patients (153 women; age 64.5 ± 16.2 years; BMI 26.6 ± 5.1 kg/m\(^2\)) received both multi-phase single-energy CT (SECT) and DECT in sequential staging examinations with a third-generation dual-source scanner. Patients were allocated to one of three BMI clusters: non-obese: <25 kg/m\(^2\) (n = 110), pre-obese: 25-29.9 kg/m\(^2\) (n = 73), and obese: >30 kg/m\(^2\) (n = 70). Radiation dose and image quality were compared for each scan. DECT examinations were evaluated regarding liver coverage within the dual-energy field of view. Results: While arterial contrast phases in DECT were associated with a higher CTDI\(_{vol}\) than in SECT (11.1 vs. 8.1 mGy; p < 0.001), replacement of true with virtual non-contrast imaging resulted in a considerably lower overall dose-length product (312.6 vs. 475.3 mGy·cm; p < 0.001). The proportion of DLP variance predictable from patient BMI was substantial in DECT (R\(^2\) = 0.738) and SECT (R\(^2\) = 0.620); however, DLP of SECT showed a stronger increase in obese patients (p < 0.001). Incomplete coverage of the liver within the dual-energy field of view was most common in the obese subgroup (17.1\%) compared with non-obese (0\%) and pre-obese patients (4.1\%). Conclusion: DECT facilitates a 30.8\% dose reduction over SECT in abdominal oncologic staging examinations. Employing dual-source scanner architecture, the risk for incomplete liver coverage increases in obese patients.},
  language  = {en}
}
@article{KraftWeickBreueretal.2022,
  author    = {Kraft, Johannes and Weick, Stefan and Breuer, Kathrin and Lutyj, Paul and Bratengeier, Klaus and Exner, Florian and Richter, Anne and Tamihardja, J{\"o}rg and Lisowski, Dominik and Polat, B{\"u}lent and Flentje, Michael},
  title     = {Treatment plan comparison for irradiation of multiple brain metastases with hippocampal avoidance whole brain radiotherapy and simultaneous integrated boost using the Varian Halcyon and the Elekta Synergy platforms},
  series = {Radiation Oncology},
  volume    = {17},
  journal   = {Radiation Oncology},
  doi       = {10.1186/s13014-022-02156-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301221},
  year      = {2022},
  abstract  = {No abstract available.},
  language  = {en}
}
@article{TamihardjaRazinskasExneretal.2021,
  author    = {Tamihardja, J{\"o}rg and Razinskas, Gary and Exner, Florian and Richter, Anne and Kessler, Patrick and Weick, Stefan and Kraft, Johannes and Mantel, Frederick and Flentje, Michael and Polat, B{\"u}lent},
  title     = {Comparison of treatment plans for hypofractionated high-dose prostate cancer radiotherapy using the Varian Halcyon and the Elekta Synergy platforms},
  series = {Journal of Applied Clinical Medical Physics},
  volume    = {22},
  journal   = {Journal of Applied Clinical Medical Physics},
  number    = {9},
  doi       = {10.1002/acm2.13380},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260722},
  pages     = {262-270},
  year      = {2021},
  abstract  = {Purpose To compare radiotherapy plans between an O-ring and a conventional C-arm linac for hypofractionated high-dose prostate radiotherapy in terms of plan quality, dose distribution, and quality assurance in a multi-vendor environment. Methods Twenty prostate cancer treatment plans were irradiated on the O-ring Varian Halcyon linac and were re-optimized for the C-arm Elekta Synergy Agility linac. Dose-volume histogram metrics for target coverage and organ at risk dose, quality assurance, and monitor units were retrospectively compared. Patient-specific quality assurance with ion chamber measurements, gamma index analysis, and portal dosimetry was performed using the Varian Portal Dosimetry system and the ArcCHECK® phantom (Sun Nuclear Corporation). Prostate-only radiotherapy was delivered with simultaneous integrated boost (SIB) volumetric modulated arc therapy (VMAT) in 20 fractions of 2.5/3.0 Gy each. Results For both linacs, target coverage was excellent and plan quality comparable. Homogeneity in PTVBoost was high for Synergy as well as Halcyon with a mean homogeneity index of 0.07 ± 0.01 and 0.05 ± 0.01, respectively. Mean dose for the organs at risk rectum and bladder differed not significantly between the linacs but were higher for the femoral heads and penile bulb for Halcyon. Quality assurance showed no significant differences in terms of ArcCHECK gamma pass rates. Median pass rate for 3\%/2 mm was 99.3\% (96.7 to 99.8\%) for Synergy and 99.8\% (95.6 to 100\%) for Halcyon. Agreement between calculated and measured dose was high with a median deviation of -0.6\% (-1.7 to 0.8\%) for Synergy and 0.2\% (-0.6 to 2.3\%) for Halcyon. Monitor units were higher for the Halcyon by approximately 20\% (p < 0.001). Conclusion Hypofractionated high-dose prostate cancer SIB VMAT on the Halcyon system is feasible with comparable plan quality in reference to a standard C-arm Elekta Synergy linac.},
  language  = {en}
}
@article{TamihardjaLutyjKraftetal.2021,
  author    = {Tamihardja, J{\"o}rg and Lutyj, Paul and Kraft, Johannes and Lisowski, Dominik and Weick, Stefan and Flentje, Michael and Polat, B{\"u}lent},
  title     = {Two-Weekly High-Dose-Rate Brachytherapy Boost After External Beam Radiotherapy for Localized Prostate Cancer: Long-Term Outcome and Toxicity Analysis},
  series = {Frontiers in Oncology},
  volume    = {11},
  journal   = {Frontiers in Oncology},
  issn      = {2234-943X},
  doi       = {10.3389/fonc.2021.764536},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250992},
  year      = {2021},
  abstract  = {Purpose Evaluation of clinical outcome of two-weekly high-dose-rate brachytherapy boost after external beam radiotherapy (EBRT) for localized prostate cancer. Methods 338 patients with localized prostate cancer receiving definitive EBRT followed by a two-weekly high-dose-rate brachytherapy boost (HDR-BT boost) in the period of 2002 to 2019 were analyzed. EBRT, delivered in 46 Gy (DMean) in conventional fractionation, was followed by two fractions HDR-BT boost with 9 Gy (D90\%) two and four weeks after EBRT. Androgen deprivation therapy (ADT) was added in 176 (52.1\%) patients. Genitourinary (GU)/gastrointestinal (GI) toxicity was evaluated utilizing the Common Toxicity Criteria for Adverse Events (version 5.0) and biochemical failure was defined according to the Phoenix definition. Results Median follow-up was 101.8 months. 15 (4.4\%)/115 (34.0\%)/208 (61.5\%) patients had low-/intermediate-/high-risk cancer according to the D`Amico risk classification. Estimated 5-year and 10-year biochemical relapse-free survival (bRFS) was 84.7\% and 75.9\% for all patients. The estimated 5-year bRFS was 93.3\%, 93.4\% and 79.5\% for low-, intermediate- and high-risk disease, respectively. The estimated 10-year freedom from distant metastasis (FFM) and overall survival (OS) rates were 86.5\% and 70.0\%. Cumulative 5-year late GU toxicity and late GI toxicity grade ≥ 2 was observed in 19.3\% and 5.0\% of the patients, respectively. Cumulative 5-year late grade 3 GU/GI toxicity occurred in 3.6\%/0.3\%. Conclusions Two-weekly HDR-BT boost after EBRT for localized prostate cancer showed an excellent toxicity profile with low GU/GI toxicity rates and effective long-term biochemical control.},
  language  = {en}
}