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Background: Surface brachytherapy, usually characterized by a high dose gradient, allows the dose to be precisely deposited in the irradiated area while protecting critical organs. When the lesion is located in the nasal or ocular region, the organ of vision must be protected. The aim of this study was to verify the dose distributions near critical organs in the head and neck region during a brachytherapy procedure using lead shielding of the eye., Methods: Anthropomorphic phantom using 3D-printing technology was prepared. The doses deposited at a point in the lens of the eye and on the surface of the eyelid, directly under the lead shield were calculated and measured using EBT3 radiochromic films. Comparison of doses planned in the treatment planning system using the TG-43 formalism, TG-186 formalism, and measured were also performed., Results: Comparing the planned and calculated doses with TG186 formalism it can be assumed that the use of lead shields is a method for protecting the organ of vision from the adverse effects of ionizing radiation., Conclusions: The decision to use a lead shield during facial surface brachytherapy procedures should be made on a patient-by-patient basis and based on model-based calculation methods recommended by TG186.

Purpose: One of the main challenges in facial region brachytherapy is fixation of vendor-delivered standard applicators. Reproducibility can be maintained; however, there are frequent problems with applicator fitting to the skin surface in pleated regions. Manually prepared individual moulds require technological facilities and highly-trained staff. This article presents 3D-printed applicator preparation for a particular patient skin brachytherapy, using low-cost equipment and free software. We described applicator preparation in a step-by-step workflow., Material and Methods: This study demonstrated preparation of a skin brachytherapy applicator for a challenging recurrent tumor located in the nose bridge. During first visit of patient, fiducial markers were placed to enclose treated region. Patient was computed tomography (CT)-scanned, and reconstruction of target volume and surrounding organs at risk (OARs) were performed using treatment planning system (TPS). In TPS on patient's surface, a 1-cm thick bolus was added as a body of applicator. Inside the bolus, source paths were designed, and pre-plan was prepared. Using Beben - DICOM to standard triangle language (STL) software, the body of applicator and source-paths from pre-planning was transformed into an STL file, which was used as a solid definition in 3D printing., Results: The printed applicator fitted very well, and its' placement was quickly consistent regarding placing and securing. CTV was slightly broader in treatment plan (0.34 cm 3 vs. 0.31 cm 3 ), and doses given to CTV were lower, except for V 150 , which was higher for the realized plan (1.15% vs. 1.83%). All reported doses to OARs were lower in the realized plan., Conclusions: A low-cost 3D printer and widely available PLA filaments seem feasible to produce individual contact applicators for skin brachytherapy. Beben - DICOM to STL software and presented workflow appear to be convenient and simple tool., Competing Interests: The authors and related institutions do not guarantee 100% security of the proposed solutions. We call for a review of the presented conduct path and subject the given procedure to all available quality control measures. The authors and related institutions do not take any responsibility for clinical application of the presented solutions. There is no conflict of interests to declare.The authors report no conflict of interest., (Copyright © 2022 Termedia.)

Purpose: Brachytherapy is a great alternative for restrictive surgical procedures in facial cancers. Moreover, dose distribution is more beneficial compared with teleradiotherapy during treatment of lesions located on anatomical curves. However, repetitiveness of application is the main issue associated with using commercial applicators. The risk of its displacement is very unfavorable due to large dose gradients in brachytherapy. The aim of this study was to develop a process of preparation of applicators using 3D printing technology., Material and Methods: In planning system, circular volumes near the nose, eye, and ear were determined on transverse layers of an anthropomorphic phantom. Next, boluses with a thickness of 5 mm and 10 mm were designed for each of the layers. Channels in the 10 mm bolus were designed in such a way to place the catheters into the layers. Prepared applicators were printed using polylactic acid (PLA) filament. Plans to irradiate the films for their calibration and plans for treatment prepared in the treatment planning system were conducted. A special phantom was created to calibrate the radiochromic films. Dose distribution around the designed applicators was measured in an anthropomorphic phantom using films within the layers of phantom. Comparison of doses was performed with two-dimensional gamma analysis using OmniPro I'mRT software., Results: The obtained results confirmed compliance of the planned and measured doses in 92%; the analysis of gamma parameter showed 1%/1 mm for acceptability level of 95%. Moreover, the initial dosimetric analysis for gamma criteria with 2%/2 mm showed compliance at 99%., Conclusions: The results of the present study confirm potential clinical usefulness of the applicators obtained with the use of 3D printing for brachytherapy., Competing Interests: The authors report no conflict of interest., (Copyright © 2021 Termedia.)

This work describes the use of 3D printing technology to create individualized boluses for patients treated with electron beam therapy for skin lesions of the eye canthi. It aimed to demonstrate the effectiveness of 3D-printed over manually fabricated paraffin boluses. The study involved 11 patients for whom the construction of individual boluses were required. CT scans of the fabricated 3D-printed boluses and paraffin boluses were acquired and superimposed onto patient CT scans to compare their fitting, bolus homogeneity, and underlying dose distribution. To quantify the level of matching, multiple metrics were utilized. Matching Level Index (ML) values ranged from 0 to 100%, where 100% indicated a perfect fit between the reference bolus (planned in treatment planning system) and 3D-printed and paraffin bolus. The average ML (± 1 SD) of the 3D-printed boluses was 95.1 ± 2.1%, compared to 46.0 ± 10.1% for the manually fabricated paraffin bolus. Correspondingly, mean doses were closer to the prescribed doses, and dose spreads were less for the dose distributions from the 3D-printed boluses, as compared to those for the manually fabricated paraffin boluses. It was concluded that 3D-printing technology is a viable method for fabricating boluses for small eye lesions and provides boluses superior to our boluses manually fabricated from paraffin sheets., (© 2016 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.)