Dosimetric comparison of RapidPlan and manually optimized plans in volumetric modulated arc therapy for prostate cancer

Kazuki Kubo; Hajime Monzen; Kentaro Ishii; Mikoto Tamura; Ryu Kawamorita; Iori Sumida; Hirokazu Mizuno; Yasumasa Nishimura

doi:10.1016/j.ejmp.2017.06.026

Dosimetric comparison of RapidPlan and manually optimized plans in volumetric modulated arc therapy for prostate cancer

Phys Med. 2017 Dec:44:199-204. doi: 10.1016/j.ejmp.2017.06.026. Epub 2017 Jul 10.

Authors

Kazuki Kubo¹, Hajime Monzen², Kentaro Ishii³, Mikoto Tamura⁴, Ryu Kawamorita³, Iori Sumida⁵, Hirokazu Mizuno⁵, Yasumasa Nishimura⁶

Affiliations

¹ Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan; Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka 550-0025, Japan.
² Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan. Electronic address: hmon@med.kindai.ac.jp.
³ Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka 550-0025, Japan.
⁴ Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan.
⁵ Department of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan.
⁶ Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan.

PMID: 28705507
DOI: 10.1016/j.ejmp.2017.06.026

Abstract

Purpose: This study evaluated whether RapidPlan based plans (RP plans) created by a single optimization, are usable in volumetric modulated arc therapy (VMAT) for patients with prostate cancer.

Methods: We used 51 previously administered VMAT plans to train a RP model. Thirty RP plans were created by a single optimization without planner intervention during optimization. Differences between RP plans and clinical manual optimization (CMO) plans created by an experienced planner for the same patients were analyzed (Wilcoxon tests) in terms of homogeneity index (HI), conformation number (CN), D_95%, and D_2% to planning target volume (PTV), mean dose, V_50Gy, V_70Gy, V_75Gy, and V_78Gy to rectum and bladder, monitor unit (MU), and multi-leaf collimator (MLC) sequence complexity.

Results: RP and CMO values for PTV D_95%, PTV D_2%, HI, and CN were significantly similar (p<0.05 for all). RP mean dose, V_50Gy, and V_70Gy to rectum were superior or comparable to CMO values; RP V_75Gy and V_78Gy were higher than in CMO plans (p<0.05). RP bladder dose-volume parameter values (except V_78Gy) were lower than in CMO plans (p<0.05). MU values were RP: 730±55MU and CMO: 580±37MU (p<0.05); and MLC sequence complexity scores were RP: 0.25±0.02 and CMO: 0.35±0.03 (p<0.05).

Conclusions: RP plans created by a single optimization were clinically acceptable in VMAT for patient with prostate cancer. Our simple model could reduce optimization time, independently of planner's skill and knowledge.

Keywords: Knowledge-based planning; Prostate cancer; RapidPlan; VMAT.

Publication types

Comparative Study

MeSH terms

Humans
Male
Organs at Risk / radiation effects
Prostatic Neoplasms / radiotherapy*
Radiometry
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods*
Radiotherapy, Intensity-Modulated* / adverse effects
Rectum / radiation effects
Urinary Bladder / radiation effects