Four-Dimensional Measurement of the Displacement of Internal Fiducial and Skin Markers During 320-Multislice Computed Tomography Scanning of Breast Cancer

作者：Yamashita Hideomi^*; Okuma Kae; Tada Keiichiro; Shiraishi Kenshiro; Takahashi Wataru; Shibata Mobayashi Shino; Sakumi Akira; Saotome Naoya; Haga Akihiro; Onoe Tsuyoshi; Ino Kenji; Akahane Masaaki; Ohtomo Kuni; Nakagawa Keiichi

来源：International Journal of Radiation Oncology, Biology, Physics, 2012, 84(2): 331-335.

DOI：10.1016/j.ijrobp.2011.12.030

• Intrafraction motion
• Computed tomography
• Breast cancer
• Internal margin

Purpose: To study the three-dimensional movement of internal tumor bed fiducial and breast skin markers, using 320-multislice computed tomography (CT); and to analyze intrafractional errors for breast cancer patients undergoing breast irradiation.
Methods and Materials: This study examined 280 markers on the skin of the breast (200 markers) and on the primary tumor bed (80 markers) of 20 patients treated by external-beam photon radiotherapy. Motion assessment was analyzed in 41 respiratory phases during 20 s of cine CT in the radiotherapy position. To assess intrafractional errors resulting from respiratory motion, four-dimensional CT scans were acquired for 20 patients.
Results: Motion in the anterioreposterior (A/P) and superior-inferior (S/I) directions showed a strong correlation (vertical bar r vertical bar > 0.7) with the respiratory curve for most markers (79% and 70%, respectively). The average marker displacements between maximum and minimum value during 20 s for the 200 breast skin metal markers were 1.1 +/- 0.3 mm, 2.1 +/- 0.6 mm, and 1.6 +/- 0.4 mm in the left-right, A/P, and S/I directions, respectively. For the 80 tumor bed clips, displacements were 0.9 +/- 0.2 mm in lefteright, 1.7 +/- 0.5 mm in A/P, and 1.1 +/- 0.3 mm in S/I. There was no significant difference in the motion between breast quadrant regions or between the primary site and the other regions.
Conclusions: Motion in primary breast tumors was evaluated with 320-multislice CT. Very little change was detected during individual radiation treatment fractions.

• 出版日期2012-10-1