Towards Effective and Efficient Patient-Specific Quality Assurance for Spot Scanning Proton Therapy

Cancers

卷:7

Steven J. Frank¹  Andrew K. Lee¹  Anita Mahajan¹  Heng Li²  Narayan Sahoo²  Falk Poenisch²  Yupeng Li²  Dennis Mackin²  Michael T. Gillin²  Xiaodong Zhang²  X. Ronald. Zhu² 

[1] Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA;

[2] Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston,TX 77030, USA;

关键词: spot scanning proton therapy;    IMPT;    SFO;    SFIB;    patient specific QA;   

DOI  :  10.3390/cancers7020631

来源: DOAJ

【 摘 要 】

An intensity-modulated proton therapy (IMPT) patient-specific quality assurance (PSQA) program based on measurement alone can be very time consuming due to the highly modulated dose distributions of IMPT fields. Incorporating independent dose calculation and treatment log file analysis could reduce the time required for measurements. In this article, we summarize our effort to develop an efficient and effective PSQA program that consists of three components: measurements, independent dose calculation, and analysis of patient-specific treatment delivery log files. Measurements included two-dimensional (2D) measurements using an ionization chamber array detector for each field delivered at the planned gantry angles with the electronic medical record (EMR) system in the QA mode and the accelerator control system (ACS) in the treatment mode, and additional measurements at depths for each field with the ACS in physics mode and without the EMR system. Dose distributions for each field in a water phantom were calculated independently using a recently developed in-house pencil beam algorithm and compared with those obtained using the treatment planning system (TPS). The treatment log file for each field was analyzed in terms of deviations in delivered spot positions from their planned positions using various statistical methods. Using this improved PSQA program, we were able to verify the integrity of the data transfer from the TPS to the EMR to the ACS, the dose calculation of the TPS, and the treatment delivery, including the dose delivered and spot positions. On the basis of this experience, we estimate that the in-room measurement time required for each complex IMPT case (e.g., a patient receiving bilateral IMPT for head and neck cancer) is less than 1 h using the improved PSQA program. Our experience demonstrates that it is possible to develop an efficient and effective PSQA program for IMPT with the equipment and resources available in the clinic.

【 授权许可】

Unknown