@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{MemmelSisarioZimmermannetal.2020, author = {Memmel, Simon and Sisario, Dmitri and Zimmermann, Heiko and Sauer, Markus and Sukhorukov, Vladimir L. and Djuzenova, Cholpon S. and Flentje, Michael}, title = {FocAn: automated 3D analysis of DNA repair foci in image stacks acquired by confocal fluorescence microscopy}, series = {BMC Bioinformatics}, volume = {21}, journal = {BMC Bioinformatics}, doi = {10.1186/s12859-020-3370-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229023}, year = {2020}, abstract = {Background Phosphorylated histone H2AX, also known as gamma H2AX, forms mu m-sized nuclear foci at the sites of DNA double-strand breaks (DSBs) induced by ionizing radiation and other agents. Due to their specificity and sensitivity, gamma H2AX immunoassays have become the gold standard for studying DSB induction and repair. One of these assays relies on the immunofluorescent staining of gamma H2AX followed by microscopic imaging and foci counting. During the last years, semi- and fully automated image analysis, capable of fast detection and quantification of gamma H2AX foci in large datasets of fluorescence images, are gradually replacing the traditional method of manual foci counting. A major drawback of the non-commercial software for foci counting (available so far) is that they are restricted to 2D-image data. In practice, these algorithms are useful for counting the foci located close to the midsection plane of the nucleus, while the out-of-plane foci are neglected. Results To overcome the limitations of 2D foci counting, we present a freely available ImageJ-based plugin (FocAn) for automated 3D analysis of gamma H2AX foci in z-image stacks acquired by confocal fluorescence microscopy. The image-stack processing algorithm implemented in FocAn is capable of automatic 3D recognition of individual cell nuclei and gamma H2AX foci, as well as evaluation of the total foci number per cell nucleus. The FocAn algorithm consists of two parts: nucleus identification and foci detection, each employing specific sequences of auto local thresholding in combination with watershed segmentation techniques. We validated the FocAn algorithm using fluorescence-labeled gamma H2AX in two glioblastoma cell lines, irradiated with 2 Gy and given up to 24 h post-irradiation for repair. We found that the data obtained with FocAn agreed well with those obtained with an already available software (FoCo) and manual counting. Moreover, FocAn was capable of identifying overlapping foci in 3D space, which ensured accurate foci counting even at high DSB density of up to similar to 200 DSB/nucleus. Conclusions FocAn is freely available an open-source 3D foci analyzer. The user-friendly algorithm FocAn requires little supervision and can automatically count the amount of DNA-DSBs, i.e. fluorescence-labeled gamma H2AX foci, in 3D image stacks acquired by laser-scanning microscopes without additional nuclei staining.}, language = {en} } @article{TamihardjaZehnerHartrampfetal.2022, author = {Tamihardja, J{\"o}rg and Zehner, Leonie and Hartrampf, Philipp E. and Cirsi, Sinan and Wegener, Sonja and Buck, Andreas K. and Flentje, Michael and Polat, B{\"u}lent}, title = {Dose-escalated salvage radiotherapy for macroscopic local recurrence of prostate cancer in the prostate-specific membrane antigen positron emission tomography era}, series = {Cancers}, volume = {14}, journal = {Cancers}, number = {19}, issn = {2072-6694}, doi = {10.3390/cancers14194956}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-290302}, year = {2022}, abstract = {Simple Summary Prostate cancer often relapses after initial radical prostatectomy, and salvage radiotherapy offers a second chance of cure for relapsed patients. Modern imaging techniques, especially prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT), enable radiation oncologists to target radiotherapy at the involved sites of disease. In a group of patients, PSMA PET/CT imaging can detect a macroscopic local recurrence with or without locoregional lymph node metastasis. In these cases, an escalation of the radiotherapy dose is often considered for controlling the visible tumor mass. As the evidence for dose-escalated salvage radiotherapy for macroscopic recurrent prostate cancer after PSMA PET/CT imaging is still limited, we address this topic in the current analysis. We found that the outcome of patients with dose-escalated salvage radiotherapy for macroscopic prostate cancer recurrence is encouragingly favorable, while the toxicity is very limited. Abstract Background: The purpose of this study was to access the oncological outcome of prostate-specific membrane antigen positron emission tomography (PSMA PET/CT)-guided salvage radiotherapy (SRT) for localized macroscopic prostate cancer recurrence. Methods: Between February 2010 and June 2021, 367 patients received SRT after radical prostatectomy. Out of the 367 screened patients, 111 patients were staged by PSMA PET/CT before SRT. A total of 59 out of these 111 (53.2\%) patients were treated for PSMA PET-positive macroscopic prostatic fossa recurrence. Dose-escalated SRT was applied with a simultaneous integrated boost at a median prescribed dose of 69.3 Gy (IQR 69.3-72.6 Gy). The oncological outcome was investigated using Kaplan-Meier and Cox regression analyses. The genitourinary (GU)/gastrointestinal (GI) toxicity evaluation utilized Common Toxicity Criteria for Adverse Events (version 5.0). Results: The median follow-up was 38.2 months. The three-year biochemical progression-free survival rate was 89.1\% (95\% CI: 81.1-97.8\%) and the three-year metastasis-free survival rate reached 96.2\% (95\% CI: 91.2-100.0\%). The cumulative three-year late grade 3 GU toxicity rate was 3.4\%. No late grade 3 GI toxicity occurred. Conclusions: Dose-escalated PSMA PET/CT-guided salvage radiotherapy for macroscopic prostatic fossa recurrence resulted in favorable survival and toxicity rates.}, language = {en} } @article{LisowskiTroemelLutyjetal.2022, author = {Lisowski, Dominik and Tr{\"o}mel, Jannik and Lutyj, Paul and Lewitzki, Victor and Hartrampf, Philipp E. and Polat, B{\"u}lent and Flentje, Michael and Tamihardja, J{\"o}rg}, title = {Health-related quality of life and clinical outcome after radiotherapy of patients with intracranial meningioma}, series = {Scientific Reports}, volume = {12}, journal = {Scientific Reports}, doi = {10.1038/s41598-022-24192-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301233}, year = {2022}, abstract = {This retrospective, single-institutional study investigated long-term outcome, toxicity and health-related quality of life (HRQoL) in meningioma patients after radiotherapy. We analyzed the data of 119 patients who received radiotherapy at our department from 1997 to 2014 for intracranial WHO grade I-III meningioma. Fractionated stereotactic radiotherapy (FSRT), intensity modulated radiotherapy (IMRT) or radiosurgery radiation was applied. The EORTC QLQ-C30 and QLQ-BN20 questionnaires were completed for assessment of HRQoL. Overall survival (OS) for the entire study group was 89.6\% at 5 years and 75.9\% at 10 years. Local control (LC) at 5 and 10 years was 82.4\% and 73.4\%, respectively. Local recurrence was observed in 22 patients (18.5\%). Higher grade acute and chronic toxicities were observed in seven patients (5.9\%) and five patients (4.2\%), respectively. Global health status was rated with a mean of 59.9 points (SD 22.3) on QLQ-C30. In conclusion, radiotherapy resulted in very good long-term survival and tumor control rates with low rates of severe toxicities but with a deterioration of long-term HRQoL.}, language = {en} } @article{TamihardjaSchortmannLawrenzetal.2021, author = {Tamihardja, J{\"o}rg and Schortmann, Max and Lawrenz, Ingulf and Weick, Stefan and Bratengeier, Klaus and Flentje, Michael and Guckenberger, Matthias and Polat, B{\"u}lent}, title = {Moderately hypofractionated radiotherapy for localized prostate cancer: updated long-term outcome and toxicity analysis}, series = {Strahlentherapie und Onkologie}, volume = {197}, journal = {Strahlentherapie und Onkologie}, issn = {0179-7158}, doi = {10.1007/s00066-020-01678-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232509}, pages = {124-132}, year = {2021}, abstract = {Purpose Evaluation of long-term outcome and toxicity of moderately hypofractionated radiotherapy using intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost treatment planning and cone beam CT-based image guidance for localized prostate cancer. Methods Between 2005 and 2015, 346 consecutive patients with localized prostate cancer received primary radiotherapy using cone beam CT-based image-guided intensity-modulated radiotherapy (IG-IMRT) and volumetric modulated arc therapy (IG-VMAT) with a simultaneous integrated boost (SIB). Total doses of 73.9 Gy (n = 44) and 76.2 Gy (n = 302) to the high-dose PTV were delivered in 32 and 33 fractions, respectively. The low-dose PTV received a dose (D95) of 60.06 Gy in single doses of 1.82 Gy. The pelvic lymph nodes were treated in 91 high-risk patients to 45.5 Gy (D95). Results Median follow-up was 61.8 months. The 5‑year biochemical relapse-free survival (bRFS) was 85.4\% for all patients and 93.3, 87.4, and 79.4\% for low-, intermediate-, and high-risk disease, respectively. The 5‑year prostate cancer-specific survival (PSS) was 94.8\% for all patients and 98.7, 98.9, 89.3\% for low-, intermediate-, and high-risk disease, respectively. The 5‑year and 10-year overall survival rates were 83.8 and 66.3\% and the 5‑year and 10-year freedom from distant metastasis rates were 92.2 and 88.0\%, respectively. Cumulative 5‑year late GU toxicity and late GI toxicity grade ≥2 was observed in 26.3 and 12.1\% of the patients, respectively. Cumulative 5‑year late grade 3 GU/GI toxicity occurred in 4.0/1.2\%. Conclusion Moderately hypofractionated radiotherapy using SIB treatment planning and cone beam CT image guidance resulted in high biochemical control and survival with low rates of late toxicity.}, language = {en} } @article{RichterWegenerBreueretal.2021, author = {Richter, Anne and Wegener, Sonja and Breuer, Kathrin and Razinskas, Gary and Weick, Stefan and Exner, Florian and Bratengeier, Klaus and Flentje, Michael and Sauer, Otto and Polat, B{\"u}lent}, title = {Comparison of sliding window and field-in-field techniques for tangential whole breast irradiation using the Halcyon and Synergy Agility systems}, series = {Radiation Oncology}, volume = {16}, journal = {Radiation Oncology}, doi = {10.1186/s13014-021-01942-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265704}, year = {2021}, abstract = {Background To implement a tangential treatment technique for whole breast irradiation using the Varian Halcyon and to compare it with Elekta Synergy Agility plans. Methods For 20 patients two comparable treatment plans with respect to dose coverage and normal tissue sparing were generated. Tangential field-in-field treatment plans (Pinnacle/Synergy) were replanned using the sliding window technique (Eclipse/Halcyon). Plan specific QA was performed using the portal Dosimetry and the ArcCHECK phantom. Imaging and treatment dose were evaluated for treatment delivery on both systems using a modified CIRS Phantom. Results The mean number of monitor units for a fraction dose of 2.67 Gy was 515 MUs and 260 MUs for Halcyon and Synergy Agility plans, respectively. The homogeneity index and dose coverage were similar for both treatment units. The plan specific QA showed good agreement between measured and calculated plans. All Halcyon plans passed portal dosimetry QA (3\%/2 mm) with 100\% points passing and ArcCheck QA (3\%/2 mm) with 99.5\%. Measurement of the cumulated treatment and imaging dose with the CIRS phantom resulted in lower dose to the contralateral breast for the Halcyon plans. Conclusions For the Varian Halcyon a plan quality similar to the Elekta Synergy device was achieved. For the Halcyon plans the dose contribution from the treatment fields to the contralateral breast was even lower due to less interleaf transmission of the Halcyon MLC and a lower contribution of scattered dose from the collimator system.}, language = {en} } @article{BratengeierHerzogWegeneretal.2017, author = {Bratengeier, Klaus and Herzog, Barbara and Wegener, Sonja and Holubyev, Kostyantyn}, title = {Finer leaf resolution and steeper beam edges using a virtual isocentre in concurrence to PTV-shaped collimators in standard distance - a planning study}, series = {Radiation Oncology}, volume = {12}, journal = {Radiation Oncology}, number = {88}, doi = {10.1186/s13014-017-0826-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157543}, year = {2017}, abstract = {Purpose: Investigation of a reduced source to target distance to improve organ at risk sparing during stereotactic irradiation (STX). Methods: The authors present a planning study with perfectly target-volume adapted collimator compared with multi-leaf collimator (MLC) at reduced source to virtual isocentre distance (SVID) in contrast to normal source to isocentre distance (SID) for stereotactic applications. The role of MLC leaf width and 20-80\% penumbra was examined concerning the healthy tissue sparing. Several prescription schemes and target diameters are considered. Results: Paddick's gradient index (GI) as well as comparison of the mean doses to spherical shells at several distances to the target is evaluated. Both emphasize the same results: the healthy tissue sparing in the high dose area around the planning target volume (PTV) is improved at reduced SVID ≤ 70 cm. The effect can be attributed more to steeper penumbra than to finer leaf resolution. Comparing circular collimators at different SVID just as MLC-shaped collimators, always the GI was reduced. Even MLC-shaped collimator at SVID 70 cm had better healthy tissue sparing than an optimal shaped circular collimator at SID 100 cm. Regarding penumbra changes due to varying SVID, the results of the planning study are underlined by film dosimetry measurements with Agility™ MLC. Conclusion: Penumbra requires more attention in comparing studies, especially studies using different planning systems. Reduced SVID probably allows usage of conventional MLC for STX-like irradiations.}, language = {en} } @article{DjuzenovaFischerKatzeretal.2021, author = {Djuzenova, Cholpon S. and Fischer, Thomas and Katzer, Astrid and Sisario, Dmitri and Korsa, Tessa and Streussloff, Gudrun and Sukhorukov, Vladimir L. and Flentje, Michael}, title = {Opposite effects of the triple target (DNA-PK/PI3K/mTOR) inhibitor PI-103 on the radiation sensitivity of glioblastoma cell lines proficient and deficient in DNA-PKcs}, series = {BMC Cancer}, volume = {21}, journal = {BMC Cancer}, doi = {10.1186/s12885-021-08930-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265826}, year = {2021}, abstract = {Background: Radiotherapy is routinely used to combat glioblastoma (GBM). However, the treatment efficacy is often limited by the radioresistance of GBM cells. Methods: Two GBM lines MO59K and MO59J, differing in intrinsic radiosensitivity and mutational status of DNA-PK and ATM, were analyzed regarding their response to DNA-PK/PI3K/mTOR inhibition by PI-103 in combination with radiation. To this end we assessed colony-forming ability, induction and repair of DNA damage by gamma H2AX and 53BP1, expression of marker proteins, including those belonging to NHEJ and HR repair pathways, degree of apoptosis, autophagy, and cell cycle alterations. Results: We found that PI-103 radiosensitized MO59K cells but, surprisingly, it induced radiation resistance in MO59J cells. Treatment of MO59K cells with PI-103 lead to protraction of the DNA damage repair as compared to drug-free irradiated cells. In PI-103-treated and irradiated MO59J cells the foci numbers of both proteins was higher than in the drug-free samples, but a large portion of DNA damage was quickly repaired. Another cell line-specific difference includes diminished expression of p53 in MO59J cells, which was further reduced by PI-103. Additionally, PI-103-treated MO59K cells exhibited an increased expression of the apoptosis marker cleaved PARP and increased subG1 fraction. Moreover, irradiation induced a strong G2 arrest in MO59J cells (similar to 80\% vs. similar to 50\% in MO59K), which was, however, partially reduced in the presence of PI-103. In contrast, treatment with PI-103 increased the G2 fraction in irradiated MO59K cells. Conclusions: The triple-target inhibitor PI-103 exerted radiosensitization on MO59K cells, but, unexpectedly, caused radioresistance in the MO59J line, lacking DNA-PK. The difference is most likely due to low expression of the DNA-PK substrate p53 in MO59J cells, which was further reduced by PI-103. This led to less apoptosis as compared to drug-free MO59J cells and enhanced survival via partially abolished cell-cycle arrest. The findings suggest that the lack of DNA-PK-dependent NHEJ in MO59J line might be compensated by DNA-PK independent DSB repair via a yet unknown mechanism.}, language = {en} } @article{TamihardjaCirsiKessleretal.2021, author = {Tamihardja, J{\"o}rg and Cirsi, Sinan and Kessler, Patrick and Razinskas, Gary and Exner, Florian and Richter, Anne and Polat, B{\"u}lent and Flentje, Michael}, title = {Cone beam CT-based dose accumulation and analysis of delivered dose to the dominant intraprostatic lesion in primary radiotherapy of prostate cancer}, series = {Radiation Oncology}, volume = {16}, journal = {Radiation Oncology}, doi = {10.1186/s13014-021-01933-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265656}, year = {2021}, abstract = {Background Evaluation of delivered dose to the dominant intraprostatic lesion (DIL) for moderately hypofractionated radiotherapy of prostate cancer by cone beam computed tomography (CBCT)-based dose accumulation and target coverage analysis. Methods Twenty-three patients with localized prostate cancer treated with moderately hypofractionated prostate radiotherapy with simultaneous integrated boost (SIB) between December 2016 and February 2020 were retrospectively analyzed. Included patients were required to have an identifiable DIL on bi-parametric planning magnetic resonance imaging (MRI). After import into the RayStation treatment planning system and application of a step-wise density override, the fractional doses were computed on each CBCT and were consecutively mapped onto the planning CT via a deformation vector field derived from deformable image registration. Fractional doses were accumulated for all CBCTs and interpolated for missing CBCTs, resulting in the delivered dose for PTV\(_{DIL}\), PTV\(_{Boost}\), PTV, and the organs at risk. The location of the index lesions was recorded according to the sector map of the Prostate Imaging Reporting and Data System (PIRADS) Version 2.1. Target coverage of the index lesions was evaluated and stratified for location. Results In total, 338 CBCTs were available for analysis. Dose accumulation target coverage of PTV\(_{DIL}\), PTV\(_{Boost}\), and PTV was excellent and no cases of underdosage in D\(_{Mean}\), D_95\%, D_02\%, and D_98\% could be detected. Delivered rectum D\(_{Mean}\) did not significantly differ from the planned dose. Bladder mean DMean was higher than planned with 19.4 ± 7.4 Gy versus 18.8 ± 7.5 Gy, p < 0.001. The penile bulb showed a decreased delivered mean DMean with 29.1 ± 14.0 Gy versus 29.8 ± 14.4 Gy, p < 0.001. Dorsal DILs, defined as DILs in the posterior medial peripheral zone of the prostate, showed a significantly lower delivered dose with a mean DMean difference of 2.2 Gy (95\% CI 1.3-3.1 Gy, p < 0.001) compared to ventral lesions. Conclusions CBCT-based dose accumulation showed an adequate delivered dose to the dominant intraprostatic lesion and organs at risk within planning limits. Cautious evaluation of the target coverage for index lesions adjacent to the rectum is warranted to avoid underdosage.}, language = {en} } @article{FischerHartmannReisslandetal.2022, author = {Fischer, Thomas and Hartmann, Oliver and Reissland, Michaela and Prieto-Garcia, Cristian and Klann, Kevin and Pahor, Nikolett and Sch{\"u}lein-V{\"o}lk, Christina and Baluapuri, Apoorva and Polat, B{\"u}lent and Abazari, Arya and Gerhard-Hartmann, Elena and Kopp, Hans-Georg and Essmann, Frank and Rosenfeldt, Mathias and M{\"u}nch, Christian and Flentje, Michael and Diefenbacher, Markus E.}, title = {PTEN mutant non-small cell lung cancer require ATM to suppress pro-apoptotic signalling and evade radiotherapy}, series = {Cell \& Bioscience}, volume = {12}, journal = {Cell \& Bioscience}, issn = {2045-3701}, doi = {10.1186/s13578-022-00778-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-299865}, year = {2022}, abstract = {Background Despite advances in treatment of patients with non-small cell lung cancer, carriers of certain genetic alterations are prone to failure. One such factor frequently mutated, is the tumor suppressor PTEN. These tumors are supposed to be more resistant to radiation, chemo- and immunotherapy. Results We demonstrate that loss of PTEN led to altered expression of transcriptional programs which directly regulate therapy resistance, resulting in establishment of radiation resistance. While PTEN-deficient tumor cells were not dependent on DNA-PK for IR resistance nor activated ATR during IR, they showed a significant dependence for the DNA damage kinase ATM. Pharmacologic inhibition of ATM, via KU-60019 and AZD1390 at non-toxic doses, restored and even synergized with IR in PTEN-deficient human and murine NSCLC cells as well in a multicellular organotypic ex vivo tumor model. Conclusion PTEN tumors are addicted to ATM to detect and repair radiation induced DNA damage. This creates an exploitable bottleneck. At least in cellulo and ex vivo we show that low concentration of ATM inhibitor is able to synergise with IR to treat PTEN-deficient tumors in genetically well-defined IR resistant lung cancer models.}, language = {en} } @article{RichterExnerBratengeieretal.2019, author = {Richter, Anne and Exner, Florian and Bratengeier, Klaus and Polat, B{\"u}lent and Flentje, Michael and Weick, Stefan}, title = {Impact of beam configuration on VMAT plan quality for Pinnacle\(^3\)Auto-Planning for head and neck cases}, series = {Radiation Oncology}, volume = {14}, journal = {Radiation Oncology}, doi = {10.1186/s13014-019-1211-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200301}, pages = {12}, year = {2019}, abstract = {Background The purpose of this study was to compare automatically generated VMAT plans to find the superior beam configurations for Pinnacle3 Auto-Planning and share "best practices". Methods VMAT plans for 20 patients with head and neck cancer were generated using Pinnacle3 Auto-Planning Module (Pinnacle3 Version 9.10) with different beam setup parameters. VMAT plans for single (V1) or double arc (V2) and partial or full gantry rotation were optimized. Beam configurations with different collimator positions were defined. Target coverage and sparing of organs at risk were evaluated based on scoring of an evaluation parameter set. Furthermore, dosimetric evaluation was performed based on the composite objective value (COV) and a new cross comparison method was applied using the COVs. Results The evaluation showed a superior plan quality for double arcs compared to one single arc or two single arcs for all cases. Plan quality was superior if a full gantry rotation was allowed during optimization for unilateral target volumes. A double arc technique with collimator setting of 15° was superior to a double arc with collimator 60° and a two single arcs with collimator setting of 15° and 345°. Conclusion The evaluation showed that double and full arcs are superior to single and partial arcs in terms of organs at risk sparing even for unilateral target volumes. The collimator position was found as an additional setup parameter, which can further improve the target coverage and sparing of organs at risk.}, language = {en} } @article{BratengeierHolubyevWegener2019, author = {Bratengeier, Klaus and Holubyev, Kostyantyn and Wegener, Sonja}, title = {Steeper dose gradients resulting from reduced source to target distance—a planning system independent study}, series = {Journal of Applied Clinical Medical Physics}, volume = {20}, journal = {Journal of Applied Clinical Medical Physics}, number = {1}, doi = {10.1002/acm2.12490}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177424}, pages = {89-100}, year = {2019}, abstract = {Purpose: To quantify the contribution of penumbra in the improvement of healthy tissue sparing at reduced source-to-axis distance (SAD) for simple spherical target and different prescription isodoses (PI). Method: A TPS-independent method was used to estimate three-dimensional (3D) dose distribution for stereotactic treatment of spherical targets of 0.5 cm radius based on single beam two-dimensional (2D) film dosimetry measurements. 1 cm target constitutes the worst case for the conformation with standard Multi-Leaf Collimator (MLC) with 0.5 cm leaf width. The measured 2D transverse dose cross-sections and the profiles in leaf and jaw directions were used to calculate radial dose distribution from isotropic beam arrangement, for both quadratic and circular beam openings, respectively. The results were compared for standard (100 cm) and reduced SAD 70 and 55 cm for different PI. Results: For practical reduction of SAD using quadratic openings, the improvement of healthy tissue sparing (HTS) at distances up to 3 times the PTV radius was at least 6\%-12\%; gradient indices (GI) were reduced by 3-39\% for PI between 40\% and 90\%. Except for PI of 80\% and 90\%, quadratic apertures at SAD 70 cm improved the HTS by up to 20\% compared to circular openings at 100 cm or were at least equivalent; GI were 3\%-33\% lower for reduced SAD in the PI range 40\%-70\%. For PI = 80\% and 90\% the results depend on the circular collimator model. Conclusion: Stereotactic treatments of spherical targets delivered at reduced SAD of 70 or 55 cm using MLC spare healthy tissue around the target at least as good as treatments at SAD 100 cm using circular collimators. The steeper beam penumbra at reduced SAD seems to be as important as perfect target conformity. The authors argue therefore that the beam penumbra width should be addressed in the stereotactic studies.}, language = {en} } @phdthesis{Haeckel2017, author = {H{\"a}ckel, Annalena}, title = {Implementierung und Umsetzbarkeit eines Tablet-gest{\"u}tzten Screenings auf Unterst{\"u}tzungsbedarf in der Radioonkologie}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154974}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {Die Inzidenz und Pr{\"a}valenz von Krebserkrankungen pr{\"a}sentiert sich in den vergangenen Jahren ungebrochen hoch. Durch die stetige Optimierung der Versorgung werden Betroffenen neuartige Optionen offeriert. Moderne Onkotherapie zeichnet sich durch sektoren{\"u}bergreifende Kooperation aus. Diese komplexen Versorgungskonzepte k{\"o}nnen durch innovative Technologien simplifiziert werden. Vorliegende Arbeit er{\"o}rtert die Frage nach der Umsetzbarkeit Tablet-gest{\"u}tzter Screenings in der Routine der Strahlenmedizin. Die Erfassung der ESAS-Items und des Unterst{\"u}tzungsbedarfs erm{\"o}glichte nach dem Vorbild kanadischer Versorgungskonzepte definierte Aussagen zur Qualit{\"a}t der medizinischen Versorgung. Im Rahmen der Studie erhielten Tumorpatienten vor der perkutanen Radiotherapie (T1) ein Tablet-gest{\"u}tztes Symptom-Screening. Das Tablet-Screening wurde von den Teilnehmern bez{\"u}glich Bedienung und Nutzerfreundlichkeit evaluiert. Nach Abschluss der Radiotherapie erfolgte eine telefonische Nachbefragung der Teilnehmer (T2). Insgesamt partizipierten 332 Krebspatienten am Tablet-Screening. 79 potentielle Studienprobanden nahmen nicht teil. Als Hauptursachen zeigten sich fehlende Zeit (21,5\%), die Teilnahme an sonstigen Studien (20,3\%) und zu hohe psychische Belastungen (17,7\%). Der Anteil der Screening-Teilnehmer mit fundierten Vorkenntnissen im Umgang mit Tablet-PCs (15,7\%) war gering. Probanden mit Tablet-Vorerfahrungen waren signifikant j{\"u}nger als Unerfahrene. Anwendung und Nutzerfreundlichkeit erlangte hohe Zustimmung. Die wenigen (21,7\%) Bef{\"u}rworter konventioneller Stift-Papier-Frageb{\"o}gen waren signifikant {\"a}lter. 219 Screening-Teilnehmer stellten ihre ausgewerteten Symptom-Frageb{\"o}gen weiteren Auswertungen zur Verf{\"u}gung. Der Performance-Status wurde von Patient und Mediziner eher divergent bewertet (ĸ=0,254). Von T1 zu T2 nahm der Anteil positiv gescreenter Probanden ab. Kurativpatienten markierten bei den ESAS-Items M{\"u}digkeit, Kurzatmigkeit und Sonstiges signifikante Symptomverbesserungen. Bei Palliativpatienten zeigte Kurzatmigkeit signifikante Verbesserung, Depressionen hingegen signifikante Verschlechterung. Der schw{\"a}chste Unterst{\"u}tzungsbedarf (23,3\%) wurde beim ,,Bedarf an Informationen beim Erstellen von Patientenverf{\"u}gungen'' registriert. Die BUKA-Studie konnte die Chancen Tablet-gest{\"u}tzter Befragungen in der Routine der Radioonkologie darstellen. Das Screening markierte durchg{\"a}ngig positive Bewertungen sowie große Akzeptanz. Die positiven Ergebnisse deckten sich mit denen anderer Studien bez{\"u}glich EDV-gest{\"u}tzter Datenerhebung. Die oftmals nicht ausreichendende Zeit zur Studienteilnahme war jedoch nicht auf eine zu zeitintensive Bedienung von Tablet-PCs zur{\"u}ckzuf{\"u}hren. Die Anzahl der Screening-Items sollte der kurzen Wartezeit der Strahlenambulanz angepasst werden. EDV-Screenings sollten dar{\"u}ber hinaus zuk{\"u}nftig bereits von zuhause absolviert werden. Die zunehmende Technisierung des Alltags l{\"a}sst den Anteil PC-erfahrener Patienten weiter ansteigen. Die Einf{\"u}hrung EDV-gest{\"u}tzter Versionen bietet eine effektive M{\"o}glichkeit des Patienten-Monitoring als Grundlage multidisziplin{\"a}rer onkologischer Versorgung. Infolge der zunehmenden PC-gest{\"u}tzten Verarbeitung hochsensibler Patientendaten ist die Gew{\"a}hrleistung vollkommener Datensicherheit dringend notwendig. Im Gegensatz zu anderen Arbeiten pr{\"a}sentierte das Studienkollektiv {\"u}berwiegend Kurativpatienten mit gutem Allgemeinzustand. Trotz geringerer Symptombelastung konnten auch hier die positiven Effekte der Radiotherapie dargestellt werden. Der hohe Unterst{\"u}tzungsbedarf erschien oftmals dem mangelnden medizinischen Verst{\"a}ndnis der Betroffenen geschuldet. Kurativpatienten {\"a}ußerten deutlich mehr Interesse aktiv an der Therapie teilzuhaben. Palliativpatienten erschienen durch das {\"U}bermaß an Therapien entkr{\"a}ftet.}, subject = {Screening}, language = {de} } @phdthesis{Maier2023, author = {Maier, Marco}, title = {Therapiezieleinsch{\"a}tzung von palliativ bestrahlten Patienten bei Erstvorstellung in der Radioonkologie}, doi = {10.25972/OPUS-32111}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-321119}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {In der vorliegenden Arbeit wurden die H{\"a}ufigkeit und m{\"o}gliche Pr{\"a}diktoren f{\"u}r eine {\"u}beroptimistische Therapiezieleinsch{\"a}tzung von palliativ bestrahlten onkologischen Patienten der Klinik und Poliklinik f{\"u}r Strahlentherapie des Universit{\"a}tsklinikum W{\"u}rzburg untersucht. Dazu wurden die Frage zur Therapiezieleinsch{\"a}tzung, die Integrated Palliative Care Outcome Scale (IPOS), das Distress-Thermometer und das Fatigue-Screening aus dem Patientenselbsteinsch{\"a}tzungsbogen, den die Patienten routinem{\"a}ßig vor dem {\"a}rztlichen Erstgespr{\"a}ch erhalten, sowie soziodemographische und krankheitsbezogene Daten aus der elektronischen Patientenakte analysiert (Untersuchungszeitraum 05/2018-05/2019). Die Einsch{\"a}tzung des Therapieziels galt als {\"u}beroptimistisch, wenn ein Patient f{\"a}lschlicherweise von dem Behandlungsziel „Heilung" ausging. Von einer realistischen Therapiezieleinsch{\"a}tzung wurde ausgegangen, wenn ein Patient von der Nichtheilbarkeit seiner Krebserkrankung ausging. Insgesamt wurden Daten von 283 Patienten ausgewertet, davon 133 Frauen (47\%) und 150 M{\"a}nner (53\%). Das mittlere Alter lag bei 66,7 Jahren (Spannweite 30-95 Jahre). Die drei h{\"a}ufigsten Tumorentit{\"a}ten waren Lungen- (26,9\%), Brust- (18,0\%) und Prostatakrebs (10,2\%). 64,7\% (183/283) der Patienten dieser Studie sch{\"a}tzten ihr Therapieziel {\"u}beroptimistisch ein. Es fanden sich statistisch signifikante Zusammenh{\"a}nge (p<0,05) mit einzelnen IPOS-Items, der bisherigen Dauer der Therapie unter palliativer Intention und dem Karnofsky-Index . Die beiden Variablen „Dauer der Therapie unter palliativer Intention" und „Karnofsky-Index" wurden in einer bin{\"a}r logistischen Regression als Pr{\"a}diktoren f{\"u}r eine {\"u}beroptimistische Therapiezieleinsch{\"a}tzung identifiziert. Da die Selbsteinsch{\"a}tzung vor der Erstbegegnung mit dem Strahlentherapeuten erfolgte, bleibt offen, inwieweit die Patienten- und Arzteinsch{\"a}tzung nach dem Aufkl{\"a}rungsgespr{\"a}ch h{\"a}ufiger {\"u}bereinstimmen als in der vorliegenden Studie (35,3\% realistische Therapiezieleinsch{\"a}tzung).}, subject = {Palliativmedizin}, language = {de} } @article{ZetzlRennerPittigetal.2021, author = {Zetzl, Teresa and Renner, Agnes and Pittig, Andre and Jentschke, Elisabeth and Roch, Carmen and van Oorschot, Birgitt}, title = {Yoga effectively reduces fatigue and symptoms of depression in patients with different types of cancer}, series = {Supportive Care in Cancer}, volume = {29}, journal = {Supportive Care in Cancer}, issn = {0941-4355}, doi = {10.1007/s00520-020-05794-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235415}, pages = {2973-2982}, year = {2021}, abstract = {Purpose Examine the effects of an 8-week yoga therapy on fatigue in patients with different types of cancer. Methods A total of 173 cancer patients suffering from mild to severe fatigue were randomly allocated to yoga intervention (n = 84) (IG) versus waitlist control group (CG) (n = 88). Yoga therapy consisted of eight weekly sessions with 60 min each. The primary outcome was self-reported fatigue symptoms. Secondary outcomes were symptoms of depression and quality of life (QoL). Data were assessed using questionnaires before (T0) and after yoga therapy for IG versus waiting period for CG (T1). Results A stronger reduction of general fatigue (P = .033), physical fatigue (P = .048), and depression (P < .001) as well as a stronger increase in QoL (P = .002) was found for patients who attended 7 or 8 sessions compared with controls. Within the yoga group, both higher attendance rate and lower T0-fatigue were significant predictors of lower T1-fatigue (P ≤ .001). Exploratory results revealed that women with breast cancer report a higher reduction of fatigue than women with other types of cancer (P = .016) after yoga therapy. Conclusion The findings support the assumption that yoga therapy is useful to reduce cancer-related fatigue, especially for the physical aspects of fatigue. Women with breast cancer seem to benefit most, and higher attendance rate results in greater reduction of fatigue. Trial registration German Clinical Trials Register DRKS00016034}, language = {en} } @article{RadeloffRamosTiradoHaddadetal.2021, author = {Radeloff, Katrin and Ramos Tirado, Mario and Haddad, Daniel and Breuer, Kathrin and M{\"u}ller, Jana and Hochmuth, Sabine and Hackenberg, Stephan and Scherzad, Agmal and Kleinsasser, Norbert and Radeloff, Andreas}, title = {Superparamagnetic iron oxide particles (VSOPs) show genotoxic effects but no functional impact on human adipose tissue-derived stromal cells (ASCs)}, series = {Materials}, volume = {14}, journal = {Materials}, number = {2}, issn = {1996-1944}, doi = {10.3390/ma14020263}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222970}, year = {2021}, abstract = {Adipose tissue-derived stromal cells (ASCs) represent a capable source for cell-based therapeutic approaches. For monitoring a cell-based application in vivo, magnetic resonance imaging (MRI) of cells labeled with iron oxide particles is a common method. It is the aim of the present study to analyze potential DNA damage, cytotoxicity and impairment of functional properties of human (h)ASCs after labeling with citrate-coated very small superparamagnetic iron oxide particles (VSOPs). Cytotoxic as well as genotoxic effects of the labeling procedure were measured in labeled and unlabeled hASCs using the MTT assay, comet assay and chromosomal aberration test. Trilineage differentiation was performed to evaluate an impairment of the differentiation potential due to the particles. Proliferation as well as migration capability were analyzed after the labeling procedure. Furthermore, the labeling of the hASCs was confirmed by Prussian blue staining, transmission electron microscopy (TEM) and high-resolution MRI. Below the concentration of 0.6 mM, which was used for the procedure, no evidence of genotoxic effects was found. At 0.6 mM, 1 mM as well as 1.5 mM, an increase in the number of chromosomal aberrations was determined. Cytotoxic effects were not observed at any concentration. Proliferation, migration capability and differentiation potential were also not affected by the procedure. Labeling with VSOPs is a useful labeling method for hASCs that does not affect their proliferation, migration and differentiation potential. Despite the absence of cytotoxicity, however, indications of genotoxic effects have been demonstrated.}, language = {en} } @article{ZetzlPittigRenneretal.2021, author = {Zetzl, Teresa and Pittig, Andre and Renner, Agnes and van Oorschott, Birgitt and Jentschke, Elisabeth}, title = {Yoga therapy to reduce fatigue in cancer: effects of reminder e-mails and long-term efficacy}, series = {Supportive Care in Cancer}, volume = {29}, journal = {Supportive Care in Cancer}, number = {12}, issn = {1433-7339}, doi = {10.1007/s00520-021-06345-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-268415}, pages = {7725-7735}, year = {2021}, abstract = {Objective To examine the efficacy of reminder e-mails to continue yoga therapy on practice frequency and fatigue in cancer patients and long-term effects of yoga on fatigue, depression, and quality of life. Methology One hundred two cancer patients who completed an 8-week yoga therapy were randomly allocated to two groups: reminder (N = 51) vs. no-reminder group (N = 51). After completing yoga therapy, the reminder group received weekly e-mails for 24 weeks, which reminded them of practicing yoga, whereas the no-reminder group did not. Primary outcomes were fatigue and practice frequency, and long-term outcomes were fatigue, depression, and quality of life. Data were assessed using questionnaires after yoga therapy (T1) and 6 months after completing yoga therapy (T2). Result A significantly stronger reduction of general (p = 0.038, d = 0.42) and emotional fatigue (p = 0.004, d = 0.59) and a higher increase of practice frequency (p = 0.015, d = 0.52) between T1 and T2 were found for the reminder group compared to the no-reminder group. In the mediation model, practice frequency as a mediator partially explained the changes in emotional fatigue (indirect effect B =  - 0.10). Long-term effects of yoga therapy regarding fatigue, depression, and quality of life were found (F > 7.46, p < 0.001, d > 0.54). Conclusion Weekly reminder e-mails after yoga therapy can positively affect general and emotional fatigue and help cancer patients with fatigue establish a regular yoga practice at home. However, higher practice frequency did not lead to higher physical or cognitive fatigue improvement, suggesting other factors that mediate efficacy on physical or cognitive fatigue, such as mindfulness or side effects of therapy.}, 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} } @phdthesis{Cirak2019, author = {Cirak, Marianne}, title = {Sedierung am Lebensende auf der Palliativstation}, doi = {10.25972/OPUS-17965}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179651}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Retrospektive Analyse von 181 Patienten, die im Zeitraum vom 01.02.2015 bis zum 31.03.2016 auf der Palliativstation des Universit{\"a}tsklinikums W{\"u}rzburg verstorben sind. Es wurde die palliative Sedierungstherapie untersucht unter folgenden Gesichtspunkten: Erfolgte sie leitliniengerecht (waren die Symptome therapierefrakt{\"a}r bzw. wurde eine proportionale Sedierung durchgef{\"u}hrt)? Wie l{\"a}sst sich die palliative Sedierungstherapie von aktiver Sterbehilfe abgrenzen? Welchen Einfluss hat das Delir? Welche Qualit{\"a}t hatte die Dokumentation? Die Autorin kommt zu dem Schluss, dass die palliative Sedierungstherapie ein wichtiges Instrument ist zur Symptomlinderung am Lebensende. Es ist auch eine sichere Therapiemaßnahme, solange sie leitliniengerecht durchgef{\"u}hrt wird. Die palliative Sedierungstherapie auf der Palliativstation der Universit{\"a}tsklinik W{\"u}rzburg konnte als leitliniengerecht best{\"a}tigt werden. Das Delir war mit einer signifikant l{\"a}ngeren Sedierungsdauer verbunden und Patienten mit Delir wiesen signifikant mehr Risikofaktoren f{\"u}r Delir auf. Der Erhebung von Risikofaktoren und der fr{\"u}hzeitigen Erkennung des Delirs kommen damit eine besondere Bedeutung zu. Eine korrekte Dokumentation ist aus rechtlichen Gesichtspunkten und aus Respekt vor dem Selbstbestimmungsrecht des Patienten sehr wichtig, hier gab es Verbesserungspotential. Eine Empfehlung zur strukturierten Durchf{\"u}hrung der palliativen Sedierungstherapie wurde von der Autorin entwickelt.}, subject = {Palliative Sedierung}, language = {de} } @article{WackExnerWegeneretal.2020, author = {Wack, Linda J. and Exner, Florian and Wegener, Sonja and Sauer, Otto A.}, title = {The impact of isocentric shifts on delivery accuracy during the irradiation of small cerebral targets — Quantification and possible corrections}, series = {Journal of Applied Clinical Medical Physics}, volume = {21}, journal = {Journal of Applied Clinical Medical Physics}, number = {5}, doi = {10.1002/acm2.12854}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218146}, pages = {56-64}, year = {2020}, abstract = {Purpose To assess the impact of isocenter shifts due to linac gantry and table rotation during cranial stereotactic radiosurgery on D\(_{98}\), target volume coverage (TVC), conformity (CI), and gradient index (GI). Methods Winston-Lutz (WL) checks were performed on two Elekta Synergy linacs. A stereotactic quality assurance (QA) plan was applied to the ArcCHECK phantom to assess the impact of isocenter shift corrections on Gamma pass rates. These corrections included gantry sag, distance of collimator and couch axes to the gantry axis, and distance between cone-beam computed tomography (CBCT) isocenter and treatment beam (MV) isocenter. We applied the shifts via script to the treatment plan in Pinnacle 16.2. In a planning study, isocenter and mechanical rotation axis shifts of 0.25 to 2 mm were applied to stereotactic plans of spherical planning target volumes (PTVs) of various volumes. The shifts determined via WL measurements were applied to 16 patient plans with PTV sizes between 0.22 and 10.4 cm3. Results ArcCHECK measurements of a stereotactic treatment showed significant increases in Gamma pass rate for all three measurements (up to 3.8 percentage points) after correction of measured isocenter deviations. For spherical targets of 1 cm3, CI was most severely affected by increasing the distance of the CBCT isocenter (1.22 to 1.62). Gradient index increased with an isocenter-collimator axis distance of 1.5 mm (3.84 vs 4.62). D98 (normalized to reference) dropped to 0.85 (CBCT), 0.92 (table axis), 0.95 (collimator axis), and 0.98 (gantry sag), with similar but smaller changes for larger targets. Applying measured shifts to patient plans lead to relevant drops in D\(_{98}\) and TVC (7\%) for targets below 2 cm\(^3\) treated on linac 1. Conclusion Mechanical deviations during gantry, collimator, and table rotation may adversely affect the treatment of small stereotactic lesions. Adjustments of beam isocenters in the treatment planning system (TPS) can be used to both quantify their impact and for prospective correction of treatment plans.}, language = {en} }