An electronic portal image device (EPID)‐based multiplatform rapid daily LINAC QA tool

Abstract

PurposeTo develop an efficient and economic daily quality research tool (DQRT) for daily check of multiplatform linear accelerators (LINACs) with flattening filter (FF) and flattening filter‐free (FFF) photon beams by using an Electronic Portal Image Device (EPID).Materials and MethodsAfter EPID calibration, the monitored parameters were analyzed from a 10 cm × 10 cm open and 60° wedge portal images measured by the EPID with 100 MU exposure. Next, the repeatability of the EPID position accuracy, long‐term stability, and linearity between image gray value and exposure were verified. Output and beam quality stability of the 6‐MV FF and FFF beams measured by DQRT with the introduced setup errors of EPID were also surveyed. Besides, some test results obtained by DQRT were compared with those measured by FC65‐G and Matrixx. At last, the tool was evaluated on three LINACs (Synergy, VersaHD, TrueBeam) for 2 months with two popular commercial QA tools as references.ResultsThere are no differences between repeatability tests for all monitored parameters. Image grayscale values obtained by EPID and exposure show good linearity. Either 6 MV FF or FFF photon beam shows minimal impact to the results. The differences between FC65‐G, Matrixx and DQRT results are negligible. Monitor results of the two commercial tools are consistent with the DQRT results collected during the 2‐month period.ConclusionWith a shorter time and procedure, the DQRT is useful to daily QA works of LINACs, producing a QA result quality similarly to or more better than the traditional tools and giving richer contents to the QA results. For hospitals with limited QA time window available or lack of funding to purchase commercial QA tools, the proposed DQRT can provide an alternative and economic approach to accomplish the task of daily QA for LINACs.

Guía para el control de calidad y seguridad en aceleradores lineales de uso clínico

“…Se han propuesto diferentes métodos para el CC que utilizan como instrumentos de medida los propios sistemas de imagen del acelerador. 84 Estos dispositivos permiten medir y analizar en poco tiempo los principales parámetros del acelerador. Algunos fabricantes ya han incorporado en sus plataformas métodos propios que controlan los principales parámetros del acelerador con una frecuencia diaria.…”

Research on the correction method for radiotherapy verification plans based on displaced electronic portal imaging device

“…Therefore, it has been widely applied in accelerator quality control, position verification, and dose verification. 1,2 In daily work, it has been observed that under the single isocenter condition, the potential shifts of the EPID may be introduced when executing portal dosimetry (PD) plans for bilateral breast cancer, pleural mesothelioma, and lymphoma. These shifts are relative to the calibration positions of EPID and result in significant discrepancies in the plan verification results.…”

Investigation of pixel scale calibration on the Elekta iView electronic portal imager

“…With the increasing use of volumetric arc therapy (VMAT) techniques and kilovoltage cone beam CT (CBCT), the main function of the megavoltage EPID panel in many departments is for use as a quality assurance (QA) tool. A number of publications describe the use of megavoltage EPID panels for tests such as MLC position calibration, dose‐output constancy, beam flatness/symmetry, radiation field size, and kilovoltage (KV) to megavoltage (MV) isocenter calibration/verification 1‐6 …”

“…A number of publications describe the use of megavoltage EPID panels for tests such as MLC position calibration, dose‐output constancy, beam flatness/symmetry, radiation field size, and kilovoltage (KV) to megavoltage (MV) isocenter calibration/verification. 1 , 2 , 3 , 4 , 5 , 6 …”

“…A number of publications describe the use of megavoltage EPID panels for tests such as MLC position calibration, dose-output constancy, beam flatness/ symmetry, radiation field size, and kilovoltage (KV) to megavoltage (MV) isocenter calibration/verification. [1][2][3][4][5][6] The EPID is typically located at an extended sourceto-panel distance, however, for many tests there is a need to specify the radiation field at the machine isocenter plane, typically 100 cm source-to-axis (SAD). To achieve this, image data defined in EPID pixels needs to be converted to distance (e.g., millimeters) at isocenter.…”