- 作者：Noriyuki Kadoya M.S.† ; ; * ; noriyuki_kadoya@yahoo.co.jp ; Yasunori Obata M.D.‡ ; ; Takahiro Kato Ph.D.† ; ; Masaru Kagiya R.T.T.¶ ; ; Tatsuya Nakamura M.D.¶ ; ; Takuya Tomoda M.D.¶ ; ; Akinori Takada M.D.¶ ; ; Kanako Takayama D.D.S.¶ ; ; Nobukazu Fuwa M.D.¶ ;
- 刊名：International Journal of Radiation Oncology*Biology*Physics
- 出版年：2011
- 出版时间：15 March 2011
- 年：2011
- 卷：79
- 期：4
- 页码：1225-1231
- 全文大小：472 K
Purpose
This study designed photon and proton treatment plans for patients treated with hypofractionated proton radiotherapy (PT) at the Southern Tohoku Proton Therapy Center (STPTC). We then calculated dosimetric parameters and compared results with simulated treatment plans for stereotactic body radiotherapy (SBRT), using dose--volume histograms to clearly explain differences in dose distributions between PT and SBRT.Methods and Materials
Twenty-one patients with stage I non-small-cell lung cancer (stage IA, n = 15 patients; stage IB, n = 6 patients) were studied. All tumors were located in the peripheral lung, and total dose was 66 Gray equivalents (GyE) (6.6 GyE/fraction). For treatment planning, beam incidence for proton beam technique was restricted to two to three directions for PT, and seven or eight noncoplanar beams were manually selected for SBRT to achieve optimal planning target volume (PTV) coverage and minimal dose to organs at risk.
Results
Regarding lung tissues, mean dose, V5, V10, V13, V15, and V20 values were 4.6 Gy, 13.2 % , 11.4 % , 10.6 % , 10.1 % , and 9.1 % , respectively, for PT, whereas those values were 7.8 Gy, 32.0 % , 21.8 % , 17.4 % , 15.3 % , and 11.4 % , respectively, for SBRT with a prescribed dose of 66 Gy. Pearson product moment correlation coefficients between PTV and dose--volume parameters of V5, V10, V15, and V20 were 0.45, 0.52, 0.58, and 0.63, respectively, for PT, compared to 0.52, 0.45, 0.71, and 0.74, respectively, for SBRT.
Conclusions
Correlations between dose--volume parameters of the lung and PTV were observed and may indicate that PT is more advantageous than SBRT when treating a tumor with a relatively large PTV or several tumors.