Carbon ion radiotherapy using fiducial markers for prostate cancer in Osaka HIMAK: Treatment planning

被引：13

作者：

Tsubouchi, Toshiro ^{[1
]}

Hamatani, Noriaki ^{[1
]}

Takashina, Masaaki ^{[1
]}

Wakisaka, Yushi ^{[1
]}

Ogawa, Atsuhiro ^{[1
]}

Yagi, Masashi ^{[2
]}

Terasawa, Ayumi ^{[1
]}

Shimazaki, Kazuyuki ^{[1
]}

Chatani, Masashi ^{[1
]}

Mizoe, Jun'etsu ^{[3
]}

Kanai, Tatsuaki ^{[1
]}

机构：

[1] Osaka Heavy Ion Therapy Ctr, Osaka, Japan

[2] Osaka Univ, Grad Sch Med, Dept Carbon Ion Radiotherapy, Suita, Osaka, Japan

[3] Hokkaido Ohno Mem Hosp, Sapporo, Hokkaido, Japan

来源：

JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS | 2021年 / 22卷 / 09期

关键词：

beam-specific planning target volume (bsPTV); carbon ions; Osaka HIMAK; RADIATION-THERAPY; PROTON THERAPY; SIMULATIONS; MOTION; FILMS;

D O I：

10.1002/acm2.13376

中图分类号：

R8 [特种医学]; R445 [影像诊断学];

学科分类号：

1002 ; 100207 ; 1009 ;

摘要：

Purpose Carbon ion radiotherapy for prostate cancer was performed using two fine needle Gold Anchor (GA) markers for patient position verification in Osaka Heavy Ion Medical Accelerator in Kansai (Osaka HIMAK). The present study examined treatment plans for prostate cases using beam-specific planning target volume (bsPTV) based on the effect of the markers on dose distribution and analysis of target movements. Materials and Methods Gafchromic EBT3 film was used to measure dose perturbations caused by markers. First, the relationships between the irradiated film density and absolute dose with different linear energy transfer distributions within a spread-out Bragg peak (SOBP) were confirmed. Then, to derive the effect of markers, two types of markers, including GA, were placed at the proximal, center, and distal depths within the same SOBP, and dose distributions behind the markers were measured using the films. The amount of internal motion of prostate was derived from irradiation results and analyzed to determine the margins of the bsPTV. Results The linearity of the film densities against absolute doses was constant within the SOBP and the amount of dose perturbations caused by the markers was quantitatively estimated from the film densities. The dose perturbation close behind the markers was smallest (<10% among depths within the SOBP regardless of types of markers) and increased with depth. The effect of two types of GAs on dose distributions was small and could be ignored in the treatment planning. Based on the analysis results of internal motions of prostate, required margins of the bsPTV were found to be 8, 7, and 7 mm in left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. Conclusion We evaluated the dose reductions caused by markers and determined the margins of the bsPTV, which was applied to the treatment using fiducial markers, using the analysis results of prostate movements.

引用

页码：242 / 251

页数：10

共 29 条

[1] Measurements of intrafraction motion and interfraction and intrafraction rotation of prostate by three-dimensional analysis of daily portal imaging with radiopaque markers [J].