Dosimetric impact of the positioning variation of tumor treating field electrodes in the PriCoTTF‐phase I/II trial
| Autor: | Nika Guberina, Wolfgang Lübcke, Teresa Schmidt, Peter Hau, Maja Guberina, Thomas Gauler, Christoph Oster, Martin Stuschke, Björn Scheffler, Lutz Lüdemann, Christoph Pöttgen, Sied Kebir, Youness Nour, Ramazan Jabbarli, Daniela Pierscianek, Ulrich Sure, Martin Glas, Lazaros Lazaridis |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
medicine.medical_treatment
Medizin non‐coplanar IMRT Standard deviation 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Hounsfield scale Medicine Dosimetry Radiation Oncology Physics Humans Radiology Nuclear Medicine and imaging Radiometry Instrumentation Electrodes Fixation (histology) Rank correlation Radiation dosimetry business.industry Radiotherapy Planning Computer-Assisted glioblastoma Radiotherapy Dosage medicine.disease tumor treating fields Radiation therapy 030220 oncology & carcinogenesis Electrode Nuclear medicine business Glioblastoma |
| Zdroj: | Journal of Applied Clinical Medical Physics |
| ISSN: | 1526-9914 |
| Popis: | Purpose: The aim of the present study based on the PriCoTTF-phase I/II trial is the quantification of skin-normal tissue complication probabilities of patients with newly diagnosed glioblastoma multiforme treated with Tumor Treating Field (TTField) electrodes, concurrent radiotherapy, and temozolomide. Furthermore, the skin-sparing effect by the clinically applied strategy of repetitive transducer array fixation around their center position shall be examined. Material and Methods: Low-dose cone-beam computed tomography (CBCT) scans of all fractions of the first seven patients of the PriCoTTF-phase I/II trial, used for image guidance, were applied for the dosimetric analysis, for precise TTField transducer array positioning and contour delineation. Within this trial, array positioning was varied from fixation-to-fixation period with a standard deviation of 1.1 cm in the direction of the largest variation of positioning and 0.7 cm in the perpendicular direction. Physical TTField electrode composition was examined and a respective Hounsfield Unit attributed to the TTField electrodes. Dose distributions in the planning CT with TTField electrodes in place, as derived from prefraction CBCTs, were calculated and accumulated with the algorithm Acuros XB. Dose-volume histograms were obtained for the first and second 2 mm scalp layer with and without migrating electrodes and compared with those with fixed electrodes in an average position. Skin toxicity was quantified according to Lyman’s model. Minimum doses in hot-spots of 0.05 cm² and 25 cm² ((Formula presented.) D₀.₀₅cm², (Formula presented.) D₂₅cm²) size in the superficial skin layers were analyzed. Results: Normal tissue complication probabilities (NTCPs) for skin necrosis ranged from 0.005% to 1.474% (median 0.111%) for the different patients without electrodes. NTCP logarithms were significantly dependent on patient (P |
| Databáze: | OpenAIRE |
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