Purpose: The newest generation of the Leksell Gamma Knife (GK) allows frame based as well as frameless treatment. We here report outcomes of a prospective non-randomized study on mask fixation (MF) versus frame fixation (FF) for GK treatment of brain metastases. Methods: The decision for FF or MF was made on a case-by-case basis. Factors considered were patients' preference, proximity of critical structures, V12 and treatment time. Either stereotactic radiosurgery or fractionated stereotactic radiotherapy in up to 3 fractions was performed. For MF, a PTV margin of 1 mm was added. Follow-up included quarterly MRI scans. The primary outcome was local control. Secondary endpoints were progression-free survival (PFS), overall survival (OS) and the incidence of radionecrosis. Results: A total of 197 lesions (169 FF and 28 MF) were treated in 76 patients (59 FF and 17 MF). 187 lesions were treated with SRS and 10 with FSRT. Median dose was 22 Gy in both groups and median follow-up was 9.3 months. There was a higher local failure rate (HR: 3.69; 95%CI: 1.13-12.0; p = 0.03) with 11 local failures in the FF and none in the MF cohort. No differences were observed between the groups for OS (median: n.r. vs. 16.9 months; HR:1.00; 95%CI: 0.41-2.46; p = 0.999) and PFS (median: 6.9 vs. 8.4 months; HR: 0.92; 95%CI: 0.47-1.79; p = 0.800). Three cases of radionecrosis occurred with FF but none with MF (p = 0.67). Conclusions: Gamma Knife treatment with MF does not result in worse outcome or increased rates of radionecrosis in this non-randomized study. (C) 2020 Elsevier B.V. All rights reserved. Radiotherapy and Oncology 147 (2020) 195-199

Comparing the accuracy of MRI/ultrasound-guided target-biopsy by transrectal biopsy (TRB) with elastic versus rigid image fusion versus transperineal biopsy (TPB) with rigid image fusion in a standardized setting.

The Gamma Knife Icon (Elekta AB, Stockholm, Sweden) allows frameless stereotactic treatment using a combination of cone beam computer tomography (CBCT), a thermoplastic mask system, and an infrared-based high-definition motion management (HDMM) camera system for patient tracking during treatment. We report on the first patient with meningioma at the left petrous bone treated with adaptive fractionated stereotactic radiotherapy (a-gkFSRT).

Zwischenbericht und erste Ergebnisse aus einer Prospektivstudie 1 und 6 Wochen nach Bestrahlungsende.

To compare the cosmetic outcome and early side effects between hypofractionated (HF) and normofractionated (NF) tangential intensity modulated radiation therapy (tIMRT) as part of breast conserving therapy of early stage breast cancer. To date, 80 early breast cancer patients older than 60 years were stratified in two groups, 43 right-sided patients to 40 Gy in 15 fractions and 37 left-sided to 50 Gy in 25 fractions. A 16 Gy boost was added to patients younger than 70 years. tIMRT was performed according to strict dosimetric limits to ensure dose homogeneity. Weekly cone beam CT was performed to enhance treatment accuracy. Based on CTC-AE v3 and LENT-SOMA scales treatment related toxicity was prospectively documented. We report on early adverse effects at 1 and 6 weeks after end of RT compared to baseline pre-RT signs and symptoms. Both groups had minor differences in average breast size (1105 cc right vs 1147 cc left) and number of patients receiving a boost (around 50% in each). Median age was 69 years in each group. Dose homogeneity did not differ significantly between both groups. In the HF and NF groups the peak incidence of acute dermatitis was at 1 week with 11.6 and 10.8% G2-dermatitis, respectively. At 6 weeks only maximum of G1-dermatitis in 20 and 16% was still observed. Hyperpigmentation was persistent between the 1st and 6th weeks and was higher in the NF group with G1+2 hyperpigmentation in 56.8% compared to 39.5% in the HF group. Breast edema reached a peak at 1 week and tended to be less incident in the HF group with G1+2 edema in 23.3% vs 32.4% in the NF group. Breast retraction was evident in around 8% of patients in both groups at baseline. It increased to 21% in the HF group at 1 week vs 16% in the NF group. However, at 6 weeks incidence was close again at 16.3% and 18.9%, respectively. No grade 3 or 4 adverse effects were observed in all previously mentioned outcome points. At 1 week G2 breast pain was doubled (to a total of 12.5%) in both groups then dropped again to baseline values (6.25%) after 6 weeks. A maximum of G3 breast pain was observed in 1 patient in each group (total 2.5%) at 6 weeks. tIMRT as part of breast conserving therapy causes minor acute side effects. The hypofractionated treatment schedule was generally better tolerated and caused relatively less cosmetic disfigurement in the early post therapeutic phase.

Purpose/Objective(s): Pencil-beam (PB) based dose calculation for treatment planning is limited by inaccuracies in regions of tissue inhomogeneities, particularly in situations with lateral electron disequilibrium as is present at tissue/lung interfaces. To overcome these limitations, a new ’’lateral disequilibrium inclusive’’ (LDI) PB based dose calculation algorithm was introduced. In this study we evaluated the accuracy of the new model by film and ionization chamber measurements and Monte Carlo simulations. Materials/Methods: To validate the performance of the new LDI algorithm implemented in Corvus 09, eight test plans were generated on inhomogeneous thorax and pelvis phantoms. In addition, three plans were calculated with a simple effective path length (EPL) algorithm on the inhomogeneous thorax phantom. To simulate homogeneous tissues, four test plans were evaluated in homogeneous phantoms (Homogeneous dose calculation (HOM)). Results:Themeanpixelpassrates andstandarddeviationsofthegamma4%/4mmtestfor thefilmmeasurementswere(96±3)% for the plans calculated with LDI, (70 ± 5)% for the plans calculated with EPL and (99 ± 1)% for the homogeneous plans. Ionization chamber measurements and Monte Carlo simulations confirmed the high accuracy of the new algorithm (dose deviations smaller or equal 4%, gamma 3%/3mm pass rates larger or equal 96%).