RESUMO
Background: The use of magnetic resonance linear accelerators (MR-LINACs) for clinical treatment has opened up new possibilities and challenges in the field of radiation oncology. However, annual quality assurance (QA) is relatively understudied due to practical considerations. Thus, to overcome the difficulty of measuring the dose with a small water phantom for TRS-398 or TG-51 in all external beam radiation treatment unit environments, such as MR compatibility, we designed a remote phantom with a three-axis changeable capacity for QA. Methods: The designed water phantom was tested under an MR environment. The water phantom system comprised of three parts: a phantom box, a dose measurement tool, and a PMD401 drive system. The UNIDOSE universal dosimeter was used to collect beam data. The manufacturer's developer tools were utilized to position the measurement. To ensure magnetic field homogeneity, a distortion phantom was prepared using sixty fish oil capsules aligned radially to distinguish the oil and free air. The phantom was scanned in both the MR simulator and computed tomography (CT), and the acquired images were analyzed to determine the position shift. Results: The dimensions of the device are 30 cm in the X-axis, 20 cm in the Y-axis, and 17 cm in the Z-axis. Total cost of materials was no more than $10,000 US dollars. Our results indicate that the device can function normally in a regular 1.5 T MR environment without interference from the magnetic field. The water phantom's traveling speed was found to be approximately 5 mm/s with a position difference confined within 6 cm intervals during normal use. The distortion test results showed that the prepared MR environment has uniform magnetic field homogeneity. Conclusions: In this study, we constructed a prototype water phantom device that can function in an MR simulator without interference between the magnetic field and electronic components. Compared to other commercially available MR-LINAC water phantoms, our device offers a more cost-effective solution for routine monthly QA. It can shorten the duration of QA tests and relieve the burden on medical physicists.
RESUMO
Background/purpose: In Taiwan, there is no independent licensing system for dental radiation technologists. A licensed medical radiation technologist who engages in dental radiology is the so-called dental radiation technologist. This study explored mainly the profile of dental radiation technologists in Taiwan. Materials and methods: This study used the methods of documentary analysis, dental radiation manpower survey, and the secondary data analysis to find the profile of dental radiation technologists in Taiwan. Results: There were currently 59 dental radiology departments and 101 dental radiation technologists (29 males and 72 females) in 57 hospitals and their branches. Of the 101 dental radiation technologists, 56 worked in the medical centers, 28 in the regional hospitals, and 17 in the district hospitals. More than half of the dental radiation technologists were concentrated in the medical centers (55.45%, 56/101) or the northern region of Taiwan (57.43%, 58/101), especially in the northern medical centers (30.69%, 31/101). Conclusion: In Taiwan, the manpower of dental radiation technologists is insufficient, and dental radiation technologists usually work in the dental departments of the hospitals. A large number of clinic dentists lack dental radiation technologists to assist in dental radiology works and the clinic dentists have to perform the dental radiology works by themselves. Therefore, a dental radiology education system should be established to design innovative dental radiology courses for radiological technology students. This in turn can provide a new practice direction for medical radiation technologists and expand their potential participation in the field of dental radiology.