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Simulation study using the spots deletion technique in spot scanning proton beam therapy for prostate cancers.
Fukumitsu, Nobuyoshi; Hayakawa, Tomokatsu; Yamashita, Tomohiro; Mima, Masayuki; Demizu, Yusuke; Suzuki, Takeshi; Soejima, Toshinori.
Afiliación
  • Fukumitsu N; Department of Radiation Oncology, Kobe Proton Center, Kobe, Hyogo 650-0047, Japan.
  • Hayakawa T; Division of Radiation Therapy, Radiation and Proton Therapy Center, Shizuoka Cancer Center, Shizuoka, Shizuoka 411-8777, Japan.
  • Yamashita T; Division of Medical Physics, Kobe Proton Center, Kobe, Hyogo 650-0047, Japan.
  • Mima M; Department of Radiation Oncology, Kobe Proton Center, Kobe, Hyogo 650-0047, Japan.
  • Demizu Y; Department of Radiation Oncology, Kobe Proton Center, Kobe, Hyogo 650-0047, Japan.
  • Suzuki T; Department of Anesthesiology, Kobe Proton Center, Kobe, Hyogo 650-0047, Japan.
  • Soejima T; Department of Radiation Oncology, Kobe Proton Center, Kobe, Hyogo 650-0047, Japan.
Mol Clin Oncol ; 16(1): 25, 2022 Jan.
Article en En | MEDLINE | ID: mdl-34909203
The aim of the present study was to investigate the effects on the dose distribution and beam delivery time in spot scanning proton beam therapy (PBT) incorporating the spot deletion technique. A spot scanning plan was created for 30 patients with prostate cancer. The plan was then modified via two processes: Spots with lower weighting depositions were deleted (process A) and spots that were distant from the clinical target volume (CTV) were deleted (process B). The dose distribution to the organs at risk (OAR), the expanded CTV (exCTV), which was defined by a uniform expansion of the CTV by a radius of 5 mm, and the beam delivery time were compared among initial and modified plans. The V50 Gy [relative biological effectiveness (RBE)] to the rectum and bladder, and V60 Gy(RBE) to the urethral bulb, inhomogeneity index (INH) of the exCTV showed a difference (P=1.1x10-14, P=6.4x10-14, P=2.7x10-7, P=3.2x10-17), although only changes by process B were significant. Modified plan by process B showed the V50 Gy(RBE) to the rectum and bladder decreased by -2.4±1.6 and -2.3±1.4%, and the V60 Gy (RBE) to the urethral bulb decreased by -15.9±19.4%. The INH of the exCTV increased by 0.05±0.03%. On the other hand, modification of the initial plan by process A did not affect the dose of the OAR, exCTV or beam delivery time. In spot scanning PBT, modification of the initial radiotherapy plan by systemic deletion of spots distant from the CTV could result in a dose reduction to the OAR.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Mol Clin Oncol Año: 2022 Tipo del documento: Article País de afiliación: Japón Pais de publicación: Reino Unido

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Mol Clin Oncol Año: 2022 Tipo del documento: Article País de afiliación: Japón Pais de publicación: Reino Unido