*Article* **Open Source 3D Printed Lung Tumor Movement Simulator for Radiotherapy Quality Assurance**

**Darío R. Quiñones 1, David Soler-Egea 1, Víctor González-Pérez 2, Johanna Reibke 1, Elena Simarro-Mondejar 1, Ricardo Pérez-Feito 3, Juan A. García-Manrique 4, Vicente Crispín <sup>2</sup> and David Moratal 1,\***


Received: 29 June 2018; Accepted: 26 July 2018; Published: 30 July 2018

**Abstract:** In OECD (Organization for Economic Co-operation and Development) countries, cancer is one of the main causes of death, lung cancer being one of the most aggressive. There are several techniques for the treatment of lung cancer, among which radiotherapy is one of the most effective and least invasive for the patient. However, it has associated difficulties due to the moving target tumor. It is possible to reduce the side effects of radiotherapy by effectively tracking a tumor and reducing target irradiation margins. This paper presents a custom electromechanical system that follows the movement of a lung tumor. For this purpose, a hysteresis loop of human lung movement during breathing was studied to obtain its characteristic movement equation. The system is controlled by an Arduino, steppers motors and a customized 3D printed mechanism to follow the characteristic human breathing, obtaining an accurate trajectory. The developed device helps the verification of individualized radiation treatment plans and permits the improvement of radiotherapy quality assurance procedures.

**Keywords:** respiratory movement; lung tumor; radiotherapy; arduino; cancer treatment; linear accelerator
