WEKO3
アイテム
Four-dimensional measurement of intrafractional respiratory prostate motion using 4DCT
https://repo.qst.go.jp/records/65693
https://repo.qst.go.jp/records/65693ede540bf-ae21-4781-a1a0-52db6994e1f6
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2015-06-30 | |||||
| タイトル | ||||||
| タイトル | Four-dimensional measurement of intrafractional respiratory prostate motion using 4DCT | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Mori, Shinichiro
× Mori, Shinichiro× 森 慎一郎 |
|||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Introduction: Prostate treatment by charged particles offers a high conformity due to their characteristic depth dose distribution known as the Bragg peak. This results in good local control with minimal dosages to the surrounding normal tissue. To benefit maximally from a highly conformal treatment precise knowledge of the tumor position and its adjacent organs at risk such as the rectum is mandatory. Respiratory motion changes anatomical and tumor position as a function of time, hence the dose to normal tissues is increased. To our knowledge, the dosimetric effect due to intrafractional motion has not yet been evaluated for prostate therapy. Our institution uses a carbon-ion beam for prostate therapy under free-breathing conditions. It may be affected by intrafractional motion. We quantified prostate motion and water equivalent pathlength (WEPL) due to respiratory induced intrafractional motion by using 4DCT. Materials and Methods: Each patient lay on the CT couch in supine position with immobilization shell device to be similar situation to treatment. 4DCT scans of 20 patients (mean, 66.7 y; s.d. 5.5 y) were acquired under free-breathing conditions using a 256 multi-slice CT scanner. The CTV was defined as the prostate and the seminal vesicle. PTV was defined by adding 10 mm to the anterior and lateral sides and 5 mm to the posterior side of the CTV We evaluated the prostate center of mass (COM) trajectory in a single respiratory motion. WEPL, which is calculated by mapping the physical length to the radiological water equivalent pathlength, for a single respiratory cycle were calculated. We set the ROI1, ROI2 and ROI3 projected region over the PTV, the anterior side and posterior side, respectively, to evaluate WEPL. Results: Intrafractional prostate motion average over all patients was 0.1mm (<0.2mm), 0.0mm (<0.2mm), 0.0mm (<0.2mm), 0.2mm (<0.5mm), 0.1mm (<0.7mm), 0.1mm (<0.5mm) for left, right, anterior, posterior, superior and inferior directions, respectively. The abdominal thickness variation map (Tn minus T50) were increased around inhalation phase. The variations of the abdominal thickness averaged over all patients are 0.7±0.6mm WEPL for ROI1, 1.2±0.4mm WEPL for ROI2 and 0.3mm±0.4mm WEPL for ROI3. Conclusion: Prostate motion were not significantly affected by respiration, however, a respiratory- induced abdominal thickness change was identified as a factor affecting dose variation even though the prostate motion was small (<0.7mm). It is important to consider the geometrical changes from the beam entrance to the target as well as the target motion especially in particle therapy. |
|||||
| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | MICRO- MINI- AND NANO- DOSIMETRY & INTERNATIONAL PROSTATE CANCER TREATMENT WORKSHOP | |||||
| 発表年月日 | ||||||
| 日付 | 2012-12-08 | |||||
| 日付タイプ | Issued | |||||
