Contents lists available at ScienceDirect Physica Medica journal homepage: www.elsevier.com/locate/ejmp Technical note Development of a 3D printed quality control tool for evaluation of x-ray beam alignment and collimation Marcus Oliveira a, ⁎ , José Carlos Barros b , Carlos Ubeda c a Department of Health Technology and Biology, Federal Institute of Bahia, Salvador, BA, Brazil b Radiologic Technologist, Federal Institute of Bahia, Salvador, BA, Brazil c Medical Technology Department, Health Sciences Faculty, Tarapaca University, Arica, Chile ARTICLE INFO Keywords: Image quality X-ray Quality control Quality assurance 3D printer ABSTRACT The aim of this work was to develop a low-cost, 3D printed tool to evaluate X-ray beam alignment and colli- mation. The study was divided into two phases: 1) the development of 3D printed prototypes; and 2) a com- parison with a commercial test object. A 3D printer was used to develop two objects that utilized 40% infill and were each printed with a different filament: PLA (polylactic acid) and ABS (acrylonitrile butadiene styrene). Two pieces of X-ray equipment were used for the beam collimation and beam alignment tests. For validation, a standard commercial tool was used, and the evaluation results of the prototypes were compared with those of the commercial tool. The tests performed with both the prototypes and the standard tool showed a deviation of ± 1 cm between the light field and the radiation field. The central ray’s perpendicularity was evaluated through the coincidence between the rod and the metallic circle. The test of central ray alignment conducted with a standard tool revealed an axis perpendicularity of 1.5°, while both prototypes presented axis perpendi- cularities of less than 3°. The prototypes proved to be effective tools and were easy to handle. The variety of printing materials that can be used and the ease with which the filaments can be acquired contribute to a low cost of production. 1. Introduction Incorrect determination of radiographic techniques, such as the delimitation of field size borders (collimation), affects radiation doses to organs as well as image quality. With the advent of computed radiography and direct digital radiography, overexposure is now common in the practice of radiographic examination [1]. Furthermore, collimation is very important in digital radiography because image receptors are highly sensitive at low levels of radiation. Therefore, every centimeter of incorrect collimation reflects an increase in radia- tion dose [2]. The radiation dose related to X-ray examination is rela- tively low, but its contribution to the collective radiation dose should be considered [3]. In order to provide the lowest possible radiation exposure to pa- tients and to ensure that diagnostic images are of an acceptable quality, all efforts should be made with regard to quality assurance [4]. Per- formance tests on X-ray equipment should be conducted to ensure the proper operation of the equipment [5]. For this purpose, specific tools and methods are used [6,7]. Currently, the application of 3D printing in medicine has provided many research opportunities related to radiology [8,9]. The extensive growth of 3D printing has led to the creation of 3D objects for trans- plants, pediatrics, and surgery [10,11]. In terms of quality control phantoms, 3D printed objects have been developed mainly for positron emission tomography (PET) and single photon emission tomography (SPECT) imaging [12,13]. However, there are still few studies [14] of 3D objects that have been developed for quality control in the context of X-ray equipment. Therefore, the aim of this work was to develop a low-cost 3D printed tool designed to evaluate X-ray beam alignment and collimation. 2. Materials and methods The study was divided into two phases: 1) the development of the 3D printed prototypes; and 2) comparison of these prototypes with commercial test objects. 2.1. 3D printed prototype design A 3D model was created using FreeCAD (version 0.16, http://www. https://doi.org/10.1016/j.ejmp.2019.07.026 Received 12 March 2019; Received in revised form 23 June 2019; Accepted 30 July 2019 ⁎ Corresponding author. E-mail address: marcusradiology@gmail.com (M. Oliveira). Physica Medica 65 (2019) 29–32 1120-1797/ © 2019 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. T