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To evaluate the long-term results after hypofractionated stereotactic photon radiotherapy (SRT) in patients with choroidal melanoma treated between 1997 and 2016. A total of 335 patients (183 male and 152 female) with choroidal melanoma unsuitable for ruthenium-106 brachytherapy or local resection were treated with linear accelerator-based SRT at the Medical University of Vienna. All patients received five fractions with either 10, 12 or 14 Gy per fraction. A complete ophthalmic examination including visual acuity and measurement of the tumor base and height using standardized A- and B-scan ultrasonography was performed every 3 months in the first 2 years, every 6 months until 5 years and yearly thereafter. Early and late adverse side effects were assessed at every follow-up visit. The median overall follow-up was 78.6 months (39.1 to 113.7 months). Local tumor control was 95.4% after 10 and 12 years, respectively. Fifty-four patients developed metastatic disease, and 31 died during the follow-up. Mean visual acuity decreased from 0.55 Snellen at baseline to 0.05 Snellen at the last individual follow-up. Ischemic retinopathy (192/335cases) and optic neuropathy (174/335cases) were the most common radiogenic side effects, followed by radiogenic cataract (n = 127), neovascular glaucoma (n = 71) and corneal epithelium defects (n = 49). Enucleation was performed in 54 patients mostly due to neovascular glaucoma (n = 41) or tumor recurrence (n = 10) during the study period. The eye retention rate was 79.7% after 10 and 12 years. Hypofractionated stereotactic photon radiotherapy showed a high rate of local tumor control for choroidal melanoma and an acceptable rate of radiogenic side effects. [ABSTRACT FROM AUTHOR]

In the current study IMPT plan robustness was evaluated with respect to inter-fractional patient positioning for various beam arrangements and two tumor indications in the cranial region. Material and methods. For 14 patients suffering from tumors in the cranial region [skull base (SB; n = 7) and paranasal sinus (PS; n = 7)] the CTV and OARs were delineated. A safety margin of 3 mm was applied to the CTV. A prescribed dose of 2 GyE was planned via three beam arrangements (α, β, γ). Beam arrangement α consisted of lateral opposed fields for both tumor groups while beam arrangement β was optimized according to respective tumor and OAR locations, using two beams only. Beam arrangement γ applied four beams in the SB group and three beams in the PS group. Dose distributions were recalculated subjected to virtual patient translations along the major anatomical axes. The following dosimetric indices were evaluated and compared to original plans: target coverage (TC), target dose homogeneity (HI), CTV median and average dose (Dmedian, Dmean). For OARs near maximum dose and average dose (D2%, Dmean) were evaluated. Results. Dose distributions were distorted after introducing shifts. In the SB group, TC and HI were significantly different for caudal, cranial and anterior shifts for all beam arrangements. For PS patients, all but right shifts differed significantly from the original plans for all beam arrangements, although clinical relevance was not reached for arrangement γ (ΔTC < 1.5%). In general, beam arrangement γ exhibited the least spread of data regarding target indices and was consequently considered the most robust. Dosimetric parameters regarding the brainstem were mostly influenced by shifts along the anterio-posterior axis. Conclusion. For cranial IMPT, set-up uncertainties may lead to pronounced deterioration of dose distributions. According to our investigations, multi-beam arrangements were dosimetrically more robust and hence preferable over two beam arrangements. [ABSTRACT FROM AUTHOR]

Four multi-layer textile samples for potential use in space suits, developed within the Planetary Exploration Textiles project of the European Space Agency, were exposed to a low energy proton beam, to characterise their effect on dose deposition in astronauts. Each textile stack contained all required layers for a potential space suit component. The influence of the textiles on proton beams was investigated using dosimetric equipment as utilised for medical purposes. The experiments were conducted at the synchrotron-based therapy and research centre MedAustron, Austria. To quantify the radiation characteristics, the water equivalent thickness of the fabrics was determined. A PEAKFINDER system (PTW, Freiburg, Germany) was positioned downstream of the textiles and the positions of the Bragg peaks were measured and compared to the range without any material in front. As reference values aluminium and lead plates were used and the results of the textiles were normalised to these materials. Furthermore, proton threshold energies for stopping protons in the suit materials were calculated. The position of the Bragg peak was shifted between 1.2mm to 2.6mm depending on the textile stacks. This corresponds to a proton threshold energy for the investigated stacks between 10–15MeV. The study showed that methods used in particle therapy are appropriate tools to quantify characteristics of space suit materials in proton beams. However, the effect of the investigated textiles on proton beams was comparable among the used fabrics. [ABSTRACT FROM AUTHOR]

Purpose: To identify modifying factors and dose-/volume-response relationships for the retina and optic nerve related to highly conformal hypofractionated radiotherapy., Patients and Methods: Seventy-three patients undergoing hypofractionated stereotactic photon radiotherapy of choroidal melanoma were included in this retrospective study. The volumes of the optic nerve receiving doses of more than 7.5 or 12 Gy, respectively, were defined. Optic nerve circumference included in the 30%, 40%, 50%, or 80% isodose (ON%) and retina included in 30% or 40% were determined as quantal effects. Univariate and multivariate analyses were performed for clinical variables as well as probit analysis to define EDx (doses where a positive response is expected in x% of the cases)., Results: Median follow-up was 90.0 (interquartile range 69.0-98.0) months. Fifty-two (71%) and 49 (67%) patients developed radiation retinopathy and optic neuropathy (any grade). Age, length of follow-up and diabetes were significant parameters regarding retinopathy. Optic neuropathy was significantly influenced by age, length of follow-up, and ON30. The probability of optic neuropathy (any grade and grade ≥ 2) significantly increases with the dose (p ranges from 0.0126 to 0.0211)., Conclusion: Treatment planning should aim at minimizing encompassing isodoses particularly in the low dose region, without compromising PTV coverage., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To evaluate side effects of hypofractionated stereotactic photon radiotherapy for patients with choroidal melanoma., Patients and Methods: Two hundred and twelve patients with choroidal melanoma unsuitable for ruthenium-106 brachytherapy or local resection were treated stereotactically at the Medical University of Vienna between 1997 and 2007 with a Linac with 6-MV photon beams in five fractions with 10, 12, or 14 Gy per fraction. Examinations for radiogenic side effects were performed at baseline and every 3 months in the first 2 years, then every 6 months until 5 years and then once a year thereafter until 10 years after radiotherapy. Adverse side effects were assessed using slit-lamp examination, funduscopy, gonioscopy, tonometry, and, if necessary, fundus photography and fluorescein angiography. Evaluations of incidence of side effects are based on an actuarial analysis., Results: One hundred and eighty-nine (89.2%) and 168 (79.2%) of the tumors were within 3 mm of the macula and the optic disc, respectively. The five most common radiotherapy side effects were retinopathy and optic neuropathy (114 cases and 107 cases, respectively), cataract development (87 cases), neovascular glaucoma (46 cases), and corneal epithelium defects (41 cases). In total, 33.6%, 38.5%, 51.2%, 75.5%, and 77.6% of the patients were free of any radiation retinopathy, optic neuropathy, cataract, neovascular glaucoma, or corneal epithelium defects 5 years after radiotherapy, respectively., Conclusion: In centrally located choroidal melanoma hypofractionated stereotactic photon radiotherapy shows a low to moderate rate of adverse long-term side effects comparable with those after proton beam radiotherapy. Future fractionation schemes should seek to further reduce adverse side effects rate while maintaining excellent local tumor control., (Copyright © 2012 Elsevier Inc. All rights reserved.)