1
|
Iijima K, Okamoto H, Takahashi K, Aikawa A, Wakita A, Nakamura S, Nishioka S, Harada K, Notake R, Sugawara A, Yoshimura R, Kunieda E, Itami J. Inter-fractional variations in the dosimetric parameters of accelerated partial breast irradiation using a strut-adjusted volume implant. JOURNAL OF RADIATION RESEARCH 2020; 61:123-133. [PMID: 31665490 PMCID: PMC7022137 DOI: 10.1093/jrr/rrz061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/23/2019] [Accepted: 04/29/2019] [Indexed: 06/10/2023]
Abstract
The aim of the study was to evaluate inter-fractional dosimetric variations for high-dose rate breast brachytherapy using a strut-adjusted volume implant (SAVI). For the nine patients included, dosimetric constraints for treatment were as follows: for the planning target volume for evaluation (PTV_Eval), the volume receiving 90, 150 and 200% of the prescribed dose (V90%,150%,200%) should be >90%, ≤50 cm3 and ≤20 cm3, respectively; the dose covering 1 cm3 (D1cc) of the organs at risk should be ≤110% of the prescribed dose; and the air volume should be ≤10% of PTV_Eval. Differences in V90%,150%,200%, D1cc and air volume ($\Delta V$ and $\Delta D$) as inter-fractional dosimetric variations and SAVI displacements were measured with pretreatment and planning computed tomography (CT) images. Inter-fractional dosimetric variations were analyzed for correlations with the SAVI displacements. The patients were divided into two groups based on the distance of the SAVI from the surface skin to assess the relationship between the insertion position of the SAVI and dosimetric parameters. The median ΔV90%,150%,200% for the PTV_Eval in all patients was -0.3%, 0.2 cm3 and 0.2 cm3, respectively. The median (range) ΔD1cc for the chest wall and surface skin was -0.8% (-18.9 to 9.4%) and 0.3% (-7.6 to 5.3%), respectively. SAVI displacement did not correlate with inter-fractional dosimetric variations. In conclusion, the dose constraints were satisfied in most cases. However, there were inter-fractional dosimetric changes due to SAVI displacement.
Collapse
Affiliation(s)
- Kotaro Iijima
- Department of Medical Physics, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
- Department of Radiation Oncology, Tokai University, School of Medicine, Isehara Shimokasuya 143, Kanagawa, 259-1193, Japan
| | - Hiroyuki Okamoto
- Department of Medical Physics, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| | - Kana Takahashi
- Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| | - Ako Aikawa
- Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| | - Akihisa Wakita
- Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| | - Satoshi Nakamura
- Department of Medical Physics, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| | - Shie Nishioka
- Department of Medical Physics, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| | - Ken Harada
- Department of Radiation Oncology, Tokai University, School of Medicine, Isehara Shimokasuya 143, Kanagawa, 259-1193, Japan
| | - Ryoichi Notake
- Department of Radiation Therapeutics and Oncology, Tokyo Medical and Dental University, Bunkyo-ku, Ushima 1-5-45, Tokyo, 113-8510, Japan
| | - Akimoto Sugawara
- Department of Radiation Oncology, Tokai University, School of Medicine, Isehara Shimokasuya 143, Kanagawa, 259-1193, Japan
| | - Ryoichi Yoshimura
- Department of Radiation Therapeutics and Oncology, Tokyo Medical and Dental University, Bunkyo-ku, Ushima 1-5-45, Tokyo, 113-8510, Japan
| | - Etsuo Kunieda
- Department of Radiation Oncology, Tokai University, School of Medicine, Isehara Shimokasuya 143, Kanagawa, 259-1193, Japan
| | - Jun Itami
- Department of Medical Physics, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
- Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan
| |
Collapse
|