Radiat Oncol J.  2013 Dec;31(4):252-259. 10.3857/roj.2013.31.4.252.

Dosimetric evaluation of Tomotherapy and four-box field conformal radiotherapy in locally advanced rectal cancer

• Yu M
• Jang HS
• Jeon DM
• Cheon GS
• Lee HC
• Chung MJ
• Kim SH
• Lee JH

• KMID: 2051147
• DOI: http://doi.org/10.3857/roj.2013.31.4.252

Abstract

PURPOSE
To report the results of dosimetric comparison between intensity-modulated radiotherapy (IMRT) using Tomotherapy and four-box field conformal radiotherapy (CRT) for pelvic irradiation of locally advanced rectal cancer.
MATERIALS AND METHODS
Twelve patients with locally advanced rectal cancer who received a short course preoperative chemoradiotherapy (25 Gy in 5 fractions) on the pelvis using Tomotherapy, between July 2010 and December 2010, were selected. Using their simulation computed tomography scans, Tomotherapy and four-box field CRT plans with the same dose schedule were evaluated, and dosimetric parameters of the two plans were compared. For the comparison of target coverage, we analyzed the mean dose, V(n Gy), D(min), D(max), radical dose homogeneity index (rDHI), and radiation conformity index (RCI). For the comparison of organs at risk (OAR), we analyzed the mean dose.
RESULTS
Tomotherapy showed a significantly higher mean target dose than four-box field CRT (p = 0.001). But, V(26.25 Gy) and V(27.5 Gy) were not significantly different between the two modalities. Tomotherapy showed higher D(max) and lower D(min). The Tomotherapy plan had a lower rDHI than four-box field CRT (p = 0.000). Tomotherapy showed better RCI than four-box field CRT (p = 0.007). For OAR, the mean irradiated dose was significantly lower in Tomotherapy than four-box field CRT.
CONCLUSION
In locally advanced rectal cancer, Tomotherapy delivers a higher conformal radiation dose to the target and reduces the irradiated dose to OAR than four-box field CRT.

Keyword

Rectal neoplasms; Helical tomotherapy; Conformal radiotherapy; Radiation dosimetry; Preoperative procedure

MeSH Terms

Appointments and Schedules
Chemoradiotherapy
Humans
Organs at Risk
Pelvis
Preoperative Care
Radiometry
Radiotherapy, Conformal*
Radiotherapy, Intensity-Modulated
Rectal Neoplasms*