Patient-specific radiotherapy quality assurance for estimating actual treatment dose

Yoshinori Tanabe, Takayuki Ishida, Hidetoshi Eto, Tatsuhiro Sera, Yuki Emoto, Mototsugu Shimokawa

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


This study aimed to evaluate the optimal method for planning computed tomography (CT) for prostate cancer radiotherapy to avoid a dose difference of ≥3% between the actual and planned treatments using multiple acquisition planning CT (MPCT). We calculated the 3-dimensional (3D) displacement error between the pelvic bone and matching fiducial marker on MPCT and cone-beam CT scans of 25 patients who underwent prostate volumetric-modulated arc therapy for prostate cancer. The correlation of the 3D displacement error and the dose difference between planned and actual treatments was calculated using least squares second-order polynomial model. The 3D displacement error showed a moderate correlation with differences between planned and accumulated treatment doses (r = 0.587, p < 0.0001). Moreover, the improvement rate of the minimum 3D displacement error showed a strong correlation with the relative error between each MPCT image (r = 0.793, p < 0.0001). Significant differences were observed between planned and actual treatment doses (p < 0.0001) in the relative 3D displacement errors of <1 mm, 1 to 3 mm, and >3 mm. The 3D displacement error on MPCT (as the selection estimation index for optimal planning CT) is useful for monitoring patient-specific intensity-modulated radiation therapy quality assurance. This new method allows to estimate dose differences from the planned dose before commencing treatment, thereby ensuring high-quality therapy. As radiotherapy quality is critical for patient outcome, these findings may contribute to better management of prostate cancer.

Original languageEnglish
Pages (from-to)e5-e10
JournalMedical Dosimetry
Issue number1
Publication statusPublished - Mar 1 2021
Externally publishedYes


  • Image-guided radiation therapy
  • Intensity-modulated radiation therapy
  • Patient-specific
  • Prostate cancer
  • Quality assurance

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Oncology
  • Radiology Nuclear Medicine and imaging


Dive into the research topics of 'Patient-specific radiotherapy quality assurance for estimating actual treatment dose'. Together they form a unique fingerprint.

Cite this