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Oki Y, Uehara K, Mizonobe K, Akasaka H, Shiota Y, Sakamoto R, Harada A, Kitatani K, Yabuuchi T, Miyazaki S, Hattori T, Mayahara H. Plan comparison of prostate stereotactic radiotherapy in spacer implant patients. J Appl Clin Med Phys 2021; 22:280-288. [PMID: 34359100 PMCID: PMC8425928 DOI: 10.1002/acm2.13387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/31/2021] [Accepted: 07/26/2021] [Indexed: 01/26/2023] Open
Abstract
In prostate stereotactic body radiation therapy (SBRT), hydrogel spacers are increasingly used. This study aimed to perform a dosimetry comparison of treatment plans using CyberKnife (CK), commonly used for prostate SBRT, Helical TomoTherapy (HT), and TrueBeam (TB) in patients with hydrogel spacer implantations. The data of 20 patients who received hydrogel spacer implantation for prostate SBRT were retrospectively analyzed. The prescription dose was 36.25 Gy in five fractions to 95% of the planning target volume (PTV; D95). The conformity index (CI), gradient index (GI), homogeneity index (HI), and dose‐volume histogram (DVH) were analyzed for the three modalities, using the same PTV margins. The monitor unit (MU) and the beam‐on‐time (BOT) values were subsequently compared. The CI of TB (0.93 ± 0.02) was significantly superior to those of CK (0.82 ± 0.03, p < 0.01) and HT (0.86 ± 0.03, p < 0.01). Similarly, the GI value of TB (3.59 ± 0.12) was significantly better than those of CK (4.31 ± 0.43, p < 0.01) and HT (4.52 ± 0.24, p < 0.01). The median doses to the bladder did not differ between the CK and TB (V18.1 Gy: 16.5% ± 4.5% vs. 15.8% ± 4.4%, p = 1.00), but were significantly higher for HT (V18.1 Gy: 33.2% ± 7.3%, p < 0.01 vs. CK, p < 0.01 vs. TB). The median rectal dose was significantly lower for TB (V18.1 Gy: 5.6% ± 4.5%) than for CK (V18.1 Gy: 11.2% ± 6.7%, p < 0.01) and HT (20.2% ± 8.3%, p < 0.01). TB had the shortest BOT (2.6 min; CK: 17.4 min, HT: 6.9 min). TB could create treatment plans dosimetrically comparable to those of CK when using the same margins, in patients with hydrogel spacers.
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Affiliation(s)
- Yuya Oki
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Kazuyuki Uehara
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Kazufusa Mizonobe
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Hiroaki Akasaka
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan.,Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yuichirou Shiota
- Division of Radiological Technology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Risako Sakamoto
- Division of Radiological Technology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Aya Harada
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Keiji Kitatani
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Tomonori Yabuuchi
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Shuichirou Miyazaki
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Takayuki Hattori
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
| | - Hiroshi Mayahara
- Division of Radiation Oncology, Kobe Minimally Invasive Cancer Center, Kobe, Hyogo, Japan
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