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Advances in Radiotherapy
& Nuclear Medicine Barcode system for immobilization device

posterior-anterior direction, thereby reducing the margins
around the clinical target volume. Alternatively, improper
use of the devices leads to increased setup error . Usually,
[3]
multiple immobilization devices are properly chosen
according to the irradiation goal and treatment position
in the simulation procedure. However, improper use of the
devices can occur during the setup in the daily therapy.
Out of the many incidents/accidents (IA) concerning
radiation therapy that have occurred , some of them pose
[4]
major threat to patient safety. In the literature , misuse of
[4]
the immobilization devices has been identified as one of
the contributing factors to IA. Based on the “humans make Figure 1. Workflow of radiotherapy in our institution. Barcode
[5]
mistakes” philosophy , it is important to build a system authentication is performed when a patient enters the LINAC room.
not needing human interference or a system that is difficult Abbreviations: ARIA: Oncology information system (Varian);
LINAC: Linear accelerator; RIS: Radiation information system.
to make mistakes. Terezakis et al. have examined IA
[6]
reports in two facilities in the United States and analyzed Solution Corporation (Yokogawa Medical Systems,
149 cases. They found that 94% of the errors reported in Tokyo, Japan). It was introduced in the Radiological
Radiation Oncology Department were associated with Information System (RIS; FUJIFILM Medical Solution
human and communication errors. Yamamoto et al. Corporation [Yokogawa Medical Systems], Tokyo, Japan)
[7]
recently analyzed incident cases from the viewpoint of and was used after the patient entered the LINAC room.
human factors that contributed to errors using variation The barcode was placed on each immobilization device
tree analysis. They concluded that human errors could be (Figure 2), and the setup information was displayed on the
reduced by applying standardized working methods. monitor. Immobilization devices used are listed in Table 1.
A solution to prevent the improper use of immobilization Immobilization devices may vary, depending on the
devices has not yet been reported. About 7.5% of IA report patient’s needs. For head fixation, a proper pillow is chosen
submitted in our Radiation Oncology Department concerns from six different pillows, and if necessary, an individual
patient setup, including improper use of immobilization shell is made. A barcode is attached to each pillow and
devices. It is important to build a system that could shell. For upper body fixation, three different types of
prevent the improper use of immobilization devices in immobilization devices have been identified, depending
advance. Therefore, we have built an authentication system on the patient’s physical figure and the extension of the
of patient’s individual therapeutic devices using barcode arm. For lower body fixation, leg immobilization differs
(barcode certification system) to prevent this problem. In based on whether to bend the knee (Knee-fix: CIVCO
this study, we showed that a barcode certification system Medical Solutions, Coralville, USA) or to stretch the
could reduce the improper use of the immobilization legs. Individual immobilization is used for high-accuracy
devices in patient positioning during radiation therapy, by treatment such as stereotaxic radiation therapy (SRT) and
reviewing the IA reports before and after the introduction volumetric modulated arc therapy (VMAT), and a barcode
of the barcode certification system. is made per each patient name and ID. Hip-fix (CIVCO
Medical Solutions, Coralville, USA) is a thermoplastic
2. Materials and methods cover for pelvis immobilization. Vac-Lok (CIVCO Medical

2.1. Radiation oncology department Solutions, Coralville, USA) is vacuum-type cushion, which
retains its shape, made for individual patient. A bolus is
The Radiation Oncology Department in the Cancer placed on the patient to increase the surface dose. There
Institute Hospital Japan has six linear accelerators (LINACs: are two different thicknesses: 5 mm and 10 mm. The couch
Varian Medical Systems, California, USA). The number of is replaceable with Clinac21EX (Varian Medical Systems,
patients treated using external irradiation is approximately California, USA). A Mylar board is used when a couch
1700/year. The workflow of radiation treatment at our is not included in the monitor unit calculation and a flat
institution is summarized in Figure 1. panel is used when a couch is included in the monitor unit
calculation. A couch rail is also used in Clinac 21EX, for
2.2. Authentication system of patient’s individual increasing the strength of the couch. The rail slides in the
therapeutic devices using barcode horizontal direction to avoid X-ray beam from under the
The barcode certification system was proposed by our couch (Figure 3). Barcode is affixed to the back of the rail;
institution and was later developed by FUJIFILM Medical therefore, it only appears and can be scanned when the rail

Volume 1 Issue 1 (2023) 2 https://doi.org/10.36922/arnm.1036