[en] Rotational IMRT is a new technique, whose value still has to be assessed. We evaluated its adequacy for the treatment of head and neck (H and N) cancer compared to the well-established step-and-shoot IMRT. A total of 15 patients, who were treated with either IMRT (13 patients) or VMAT (2 patients) in the H and N region, were chosen. For each patient, a treatment plan with the respective other technique was calculated. To compare the resulting dose distributions, the dose-volume histograms (DVHs) were evaluated. To quantify the differences, a new quality index (QI) was introduced, as a measure of the planning target volume (PTV) coverage and homogeneity. A conformity function (CF) was defined to estimate normal tissue sparing. The QI for VMAT amounts to 36.3, whereas for IMRT the mean value is 66.5, indicating better PTV coverage as well as less overdosage for the rotational technique. While the sparing of organs at risk (OAR) was similar for both techniques, the CF shows a significantly better sparing of healthy tissue for all doses with VMAT treatment. VMAT results in dose distributions for H and N patients that are at least comparable with treatments performed with step-and-shoot IMRT. Two new tools to quantify the quality of dose distributions are presented and have proven to be useful.

[en] The current study aimed to compare contouring of glandular tissue only (gCTV) with the clinical target volume (CTV) as defined according to European Society for Radiotherapy and Oncology (ESTRO) guidelines (eCTV) and historically treated volumes (marked by wire and determined by palpation and anatomic landmarks) in breast cancer radiotherapy. A total of 56 consecutive breast cancer patients underwent treatment planning based solely on anatomic landmarks/wire markings ("wire based"). From these treatment plans, the 50% and 95% isodoses were transferred as structures and compared to the following CT-based volumes: eCTV; a Hounsfield unit (HU)-based automatic contouring of the gCTV; and standardized planning target volumes (PTVs) generated with 1-cm safety margins (resulting in the ePTVs and gPTVs, respectively). The 95% isodose volume of the wire-based plan was larger than the eCTV by 352.39 ± 176.06 cm${}^3$ but smaller than the ePTV by 157.58 ± 189.32 cm${}^3$. The 95% isodose was larger than the gCTV by 921.20 ± 419.78 cm${}^3$ and larger than the gPTV by 190.91 ± 233.49 cm${}^3$. Patients with larger breasts had significantly less glandular tissue than those with small breasts. There was a trend toward a lower percentage of glandular tissue in older patients. Historical wire and anatomic landmarks-based treatment planning sufficiently covers the glandular tissue and the theoretical gPTV generated for the glandular tissue. Modern CT-based CTV and PTV definition according to ESTRO results in a larger treated volume than the historical wire-based techniques. HU-standardized glandular tissue contouring results in a significantly smaller CTV and might be an option for reducing the treatment volume and improving reproducibility of contouring between institutions.

[en] To report on the Erlangen (UK-Er) experience with linear accelerator stereotactic body radiation therapy (LINAC SBRT) for adrenal metastasis from various primary tumors. 33 patients were treated. Primary sites included lung (n = 19), melanoma (n = 8), colorectal (n = 2), hepatocellular (n = 1), esophageal (n = 2), and breast cancer (n = 1). 14 patients were treated palliatively, 19 patients were treated with local curative intent. Treatment planning was done based on an exhale, mid-ventilation, and inspiration CT series. Further planning CTs were done to check for the correctness of the breathing pattern. Irradiation was performed using a NOVALIS (Varian, Palo Alto, CA, USA; Brainlab AG, München, Germany) linear accelerator. The isocenter was verified before each treatment session using the BrainLab ExacTrac$\mathrm{\circledR <!--\; ??\; -->}$ (Brainlab AG, München, Germany) system to minimize setup errors. Dose was prescribed to the planning target volume (PTV) surrounding 90% isodose. Depending on their overall performance status and prognosis, patients received clinical check-ups and radiological imaging. Median follow-up was 11 months. IBM SPSS v. 24 was used for univariate analysis using Kaplan-Meier curves, nonparametric Kruskal-Wallis test, and the chi-square test for frequency distributions. Toxicity was graded according to NCI CTCAE v4.0. Depending on radiologic imaging, patients were classified as stable, regression, and progression. Median survival was 11 months, median PFS was 5 months. Median local failure-free survival was 21 months. Patients who were treated with curative intent showed a better survival curve (p $<$ 0.0001) and PFS (p = 0.004). BED ranged from 42 to 108.8 Gy, median BED was 67.2 Gy. Three BED groups were formed. Overall survival curves differed significantly (p = 0.046), favoring the high-dose group. 21 patients were free from any adverse events or discomfort. In 7 cases, a grade I toxicity was noted. (orig.)

[en] Marital status is a well-described prognostic factor in patients with gliomas but the observed survival difference is unexplained in the available population-based studies. A series of 57 elderly glioblastoma patients (≥70 years) were analyzed retrospectively. Patients received radiotherapy or chemoradiation with temozolomide. The prognostic significance of marital status was assessed. Disease complications, toxicity, and treatment delivery were evaluated in detail. Overall survival was significantly higher in married than in unmarried patients (median, 7.9 vs. 4.0 months; p = 0.006). The prognostic significance of marital status was preserved in the multivariate analysis (HR, 0.41; p = 0.011). Married patients could receive significantly higher daily temozolomide doses (mean, 53.7 mg/m"2 vs. 33.1 mg/m"2; p = 0.020), were more likely to receive maintenance temozolomide (45.7 % vs. 11.8 %; p = 0.016), and had to be hospitalized less frequently during radiotherapy (55.0 % vs. 88.2 %; p = 0.016). Of the patients receiving temozolomide, married patients showed significantly lower rates of hematologic and liver toxicity. Most complications were infectious or neurologic in nature. Complications of any grade were more frequent in unmarried patients (58.8 % vs. 30.0 %; p = 0.041) with the incidence of grade 3-5 complications being particularly elevated (47.1 % vs. 15.0 %; p = 0.004). We found poorer treatment delivery as well as an unexpected severe increase in toxicity and disease complications in elderly unmarried glioblastoma patients. Marital status may be an important predictive factor for clinical decision-making and should be addressed in further studies. (orig.)

[en] Intracranial arteriovenous malformations (AVMs) may show a harmful development. AVMs are treated by surgery, embolization, or radiation therapy. This study investigated obliteration rates and side effects in patients with AVMs treated by radiation therapy. A total of 40 cases treated between 2005 and 2013 were analyzed. Single-dose stereotactic radiosurgery (SRS) was received by 13 patients and 27 received hypofractionated stereotactic radiation therapy (HSRT). In 20 patients, endovascular embolization had been performed prior to irradiation and 24 patients (60 %) had a history of previous intracranial hemorrhage. Treatment resulted in complete obliteration (CO) in 23/40 cases and partial obliteration in 8/40. CO was achieved in 85 % of patients receiving SRS compared to 44 % of those receiving HSRT. In the HSRT group, a first indication of an influence of AVM volume on obliteration rate was found. Equivalent 2 Gy fraction doses (EQD2) >70 Gy showed an obliteration rate of 50 %. Prior embolization was significantly associated with a higher portion of CO (p = 0.032). Median latency period (24.2 vs. 26 months) until CO was similar in both groups (SRS vs. HSRT). The rate of intracranial hemorrhage in patients with no prior bleeding events was 0 %. Excellent obliteration rates were achieved by SRS. Consistent with the literature, this data analysis suggests that the results of HSRT are volume-dependent. Furthermore, regimens with EQD2 doses >70 Gy appear more likely to achieve obliteration than schemes with lower doses. The findings indicate that radiation therapy does not increase the risk of bleeding. Prior embolization may have a good prognostic impact. (orig.)

[en] The aim of this publication is to present long-term data on functional outcomes and tumor control in a cohort of 107 patients treated with stereotactic radiotherapy (RT) for vestibular schwannoma. Included were 107 patients with vestibular schwannoma (primary or recurrent following resection) treated with stereotactic RT (either fractioned or single-dose radiosurgery) between October 2002 and December 2013. Local control and functional outcomes were determined. Analysis of hearing preservation was limited to a subgroup of patients with complete audiometric data collected before treatment and during follow-up. Vestibular function test (FVT) results could be analyzed in a subset of patients and were compared to patient-reported dizziness. After a mean follow-up of 46.3 months, actuarial local control for the whole cohort was 100% after 2, 97.6% after 5, and 94.1% after 10 years. In patients with primary RT, serviceable hearing was preserved in 72%. Predictors for preservation of serviceable hearing in multivariate analysis were time of follow-up (odds ratio, OR = 0.93 per month; p = 0.021) and pre-RT tumor size (Koos stage I-IIa vs. IIb-IV; OR = 0.15; p = 0.031). Worsening of FVT results was recorded in 17.6% (N = 3). Profound discrepancy of patient-reported dizziness and FVT results was observed after RT. In patients with primary RT, worsening of facial nerve function occurred in 1.7% (N = 1). Stereotactic RT of vestibular schwannoma provides good functional outcomes and high control rates. Dependence of hearing preservation on time of follow-up and initial tumor stage has to be considered. (orig.)

[en] Radiation oncology is an essential component of therapeutic oncology and necessitates well-trained personnel. Multicatheter brachytherapy (MCBT) is one radiotherapeutic option for early-stage breast cancer treatment. However, specialized hands-on training for MCBT is not currently included in the curriculum for residents. A recently developed hands-on brachytherapy workshop has demonstrated promising results in enhancing knowledge and practical skills. Nevertheless, these simulation-based teaching formats necessitate more time and financial resources. Our analyses include computational models for the implementation and delivery of this workshop and can serve as a basis for similar educational initiatives. This study aimed to assess the cost-effectiveness of a previously developed and evaluated breast brachytherapy simulation workshop. Using a micro-costing approach, we estimated costs at a detailed level by considering supplies, soft- and hardware, and personnel time for each task. This method also allows for a comprehensive evaluation of the costs associated with implementing new medical techniques. The workshop costs were divided into two categories: development and workshop execution. The cost analysis was conducted on a per-participant basis, and the impact on knowledge improvement was measured using a questionnaire. The total workshop costs were determined by considering the initial workshop setup expenses including the development and conceptualization of the course with all involved collaborators, as well as the costs incurred for each individual course. The workshop was found to be financially efficient, with a per-participant cost of € 39, considering the industrial sponsorship provided for brachytherapy equipment. In addition, we assessed the workshop's efficacy by analyzing participant feedback using Likert scale evaluations. The findings indicated a notable enhancement in both theoretical and practical skills among the participants. Moreover, the cost-to-benefit ratio (CBFR) analysis demonstrated a CBFR of € 13.53 for each Likert point increment. The hands-on brachytherapy workshop proved to be a valuable and approximately cost-effective educational program, leading to a significant enhancement in the knowledge and skills of the participants. Without the support of industrial sponsorship, the costs would have been unattainable.

[en] To evaluate the interobserver variability of gross tumor volume (GTV) - delineation of Dominant Intraprostatic Lesions (DIPL) in patients with prostate cancer using published MRI criteria for multiparametric MRI at 3 Tesla by 6 different observers. 90 GTV-datasets based on 15 multiparametric MRI sequences (T2w, diffusion weighted (DWI) and dynamic contrast enhanced (DCE)) of 5 patients with prostate cancer were generated for GTV-delineation of DIPL by 6 observers. The reference GTV-dataset was contoured by a radiologist with expertise in diagnostic imaging of prostate cancer using MRI. Subsequent GTV-delineation was performed by 5 radiation oncologists who received teaching of MRI-features of primary prostate cancer before starting contouring session. GTV-datasets were contoured using Oncentra Masterplan® and iplan® Net. For purposes of comparison GTV-datasets were imported to the Artiview® platform (Aquilab®), GTV-values and the similarity indices or Kappa indices (KI) were calculated with the postulation that a KI > 0.7 indicates excellent, a KI > 0.6 to < 0.7 substantial and KI > 0.5 to < 0.6 moderate agreement. Additionally all observers rated difficulties of contouring for each MRI-sequence using a 3 point rating scale (1 = easy to delineate, 2 = minor difficulties, 3 = major difficulties). GTV contouring using T2w (KI-T2w = 0.61) and DCE images (KI-DCE = 0.63) resulted in substantial agreement. GTV contouring using DWI images resulted in moderate agreement (KI-DWI = 0.51). KI-T2w and KI-DCE was significantly higher than KI-DWI (p = 0.01 and p = 0.003). Degree of difficulty in contouring GTV was significantly lower using T2w and DCE compared to DWI-sequences (both p < 0.0001). Analysis of delineation differences revealed inadequate comparison of functional (DWI, DCE) to anatomical sequences (T2w) and lack of awareness of non-specific imaging findings as a source of erroneous delineation. Using T2w and DCE sequences at 3 Tesla for GTV-definition of DIPL in prostate cancer patients by radiation oncologists with knowledge of MRI features results in substantial agreement compared to an experienced MRI-radiologist, but for radiotherapy purposes higher KI are desirable, strengthen the need for expert surveillance. DWI sequence for GTV delineation was considered as difficult in application

[en] The new Medical Licensing Regulations 2025 (Ärztliche Approbationsordnung, ÄApprO) require the development of competence-oriented teaching formats. In addition, there is a great need for high-quality teaching in the field of radiation oncology, which manifests itself already during medical school. For this reason, we developed a simulation-based, hands-on medical education format to teach competency in performing accelerated partial breast irradiation (APBI) with interstitial multicatheter brachytherapy for early breast cancer. In addition, we designed realistic breast models suitable for teaching both palpation of the female breast and implantation of brachytherapy catheters. From June 2021 to July 2022, 70 medical students took part in the hands-on brachytherapy workshop. After a propaedeutic introduction, the participants simulated the implantation of single-lead catheters under supervision using the silicone-based breast models. Correct catheter placement was subsequently assessed by CT scans. Participants rated their skills before and after the workshop on a six-point Likert scale in a standardized questionnaire. Participants significantly improved their knowledge-based and practical skills on APBI in all items as assessed by a standardized questionnaire (mean sum score 42.4 before and 16.0 after the course, p < 0.001). The majority of respondents fully agreed that the workshop increased their interest in brachytherapy (mean 1.15, standard deviation [SD] 0.40 on the six-point Likert scale). The silicone-based breast model was found to be suitable for achieving the previously defined learning objectives (1.19, SD 0.47). The learning atmosphere and didactic quality were rated particularly well (mean 1.07, SD 0.26 and 1.13, SD 0.3 on the six-point Likert scale). The simulation-based medical education course for multicatheter brachytherapy can improve self-assessed technical competence. Residency programs should provide resources for this essential component of radiation oncology. This course is exemplary for the development of innovative practical and competence-based teaching formats to meet the current reforms in medical education.

[en] The aim of this study was to analyze the heart dose for left-sided breast cancer that can be achieved during daily practice in patients treated with multicatheter brachytherapy (MCBT) accelerated partial-breast irradiation (APBI) and deep-inspiration breath-hold (DIBH) whole-breast irradiation (WBI) using a simultaneous integrated tumor bed boost (SIB)---two different concepts which nonetheless share some patient overlap. We analyzed the nominal average dose (Dmean) to the heart as well as the biologically effective dose (BED) and the equivalent dose in 2-Gy fractions (EQD2) for an α/β of 3 in 30 MCBT-APBI patients and 22 patients treated with DIBH plus SIB. For further dosimetric comparison, we contoured the breast planning target volume (PTV) in each of the brachytherapy planning CTs according to the ESTRO guidelines and computed tangential field plans. Mean dose (Dmean), EQD2 Dmean, and BED Dmean for three dosing schemes were calculated: 50 Gy/25 fractions and two hypofractionated regimens, i.e., 40.05 Gy/15 fractions and 26 Gy/5 fractions. Furthermore, we calculated tangential field plans without a boost for the 22 cases treated with SIB with the standard dosing scheme of 40.05 Gy/15 fractions. MCBT and DIBH radiation therapy both show low-dose exposure of the heart. As expected, hypofractionation leads to sparing of the heart dose. Although MCBT plans were not optimized regarding dose to the heart, Dmean differed significantly between MCBT and DIBH (1.28 Gy vs. 1.91 Gy, p < 0.001) in favor of MCBT, even if the Dmean in each group was very low. In MCBT radiation, the PTV-heart distance is significantly associated with the dose to the heart (p < 0.001), but it is not in DIBH radiotherapy using SIB. In daily practice, both DIBH radiation therapy as well as MCBT show a very low heart exposure and may thus reduce long term cardiac morbidity as compared to currently available long-term clinical data of patients treated with conventional tangential field plans in free breathing. Our analysis confirms particularly good cardiac sparing with MCBT-APBI, so that this technique should be offered to patients with left-sided breast cancer if the tumor-associated eligibility criteria are fulfilled.