NTCP modeling analysis of acute hematologic toxicity in whole pelvic radiation therapy for gynecologic malignancies : A dosimetric comparison of IMRT and spot-scanning proton therapy (SSPT)

• Yoshimura, Takaaki

• Kinoshita, Rumiko

• Onodera, Shunsuke

• Toramatsu, Chie

• Suzuki, Ryusuke

• Ito, Yoichi M.

• Takao, Seishin

• Matsuura, Taeko

• Matsuzaki, Yuka

• Umegaki, Kikuo

• Shirato, Hiroki

• Shimizu, Shinichi

抄録

Purpose: This treatment planning study was conducted to determine whether spot scanning proton beam therapy (SSPT) reduces the risk of grade ⩾3 hematologic toxicity (HT3+) compared with intensity modulated radiation therapy (IMRT) for postoperative whole pelvic radiation therapy (WPRT). Methods and materials: The normal tissue complication probability (NTCP) of the risk of HT3+ was used as an in silico surrogate marker in this analysis. IMRT and SSPT plans were created for 13 gynecologic malignancy patients who had received hysterectomies. The IMRT plans were generated using the 7-fields step and shoot technique. The SSPT plans were generated using anterior-posterior field with single field optimization. Using the relative biological effectives (RBE) value of 1.0 for IMRT and 1.1 for SSPT, the prescribed dose was 45 Gy(RBE) in 1.8 Gy(RBE) per fractions for 95% of the planning target volume (PTV). The homogeneity index (HI) and the conformity index (CI) of the PTV were also compared. Results: The bone marrow (BM) and femoral head doses using SSPT were significantly lower than with IMRT. The NTCP modeling analysis showed that the risk of HT3+ using SSPT was significantly lower than with IMRT (NTCP = 0.04 ± 0.01 and 0.19 ± 0.03, p = 0.0002, respectively). There were no significant differences in the CI and HI of the PTV between IMRT and SSPT (CI = 0.97 ± 0.01 and 0.96 ± 0.02, p = 0.3177, and HI = 1.24 ± 0.11 and 1.27 ± 0.05, p = 0.8473, respectively). Conclusion: The SSPT achieves significant reductions in the dose to BM without compromising target coverage, compared with IMRT. The NTCP value for HT3+ in SSPT was significantly lower than in IMRT.

収録刊行物

• Physica medica : European journal of medical physics

  Physica medica : European journal of medical physics 32 (9), 1095-1102, 2016-09

  Elsevier

キーワード

• Whole pelvic radiation therapy
• Spot-scanning proton therapy
• LKB-NTCP model analysis
• Treatment planning study

詳細情報

• CRID: 1050001202927753216
• NII論文ID: 120005972937
• HANDLE: 2115/64570
• ISSN: 11201797
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles