Yiling Zeng, Hong Quan, Qi Zhang, Wei Wang, Xu Liu, Bin Qin, Bo Pang, Muyu Liu, Shuoyan Chen, Kunyu Yang, Yu Chang, Zhiyong Yang
{"title":"基于通用范围移位器的多能质子FLASH-RT处理参数考虑。","authors":"Yiling Zeng, Hong Quan, Qi Zhang, Wei Wang, Xu Liu, Bin Qin, Bo Pang, Muyu Liu, Shuoyan Chen, Kunyu Yang, Yu Chang, Zhiyong Yang","doi":"10.1002/mp.70039","DOIUrl":null,"url":null,"abstract":"<div>\n \n \n <section>\n \n <h3> Background</h3>\n \n <p>Compared to conventional dose rate irradiation, ultra-high dose rate irradiation provides superior normal tissue sparing. Multi-energy proton beams combined with a universal range shifter (URS) and fast energy-switching gantry enable ultra-high dose rate delivery.</p>\n </section>\n \n <section>\n \n <h3> Purpose</h3>\n \n <p>This study investigates the effects of the URS, planning parameters, and patient selection on multi-energy Bragg peak (MEBP) proton FLASH radiotherapy (FLASH-RT) plans.</p>\n </section>\n \n <section>\n \n <h3> Methods</h3>\n \n <p>Single-field plans were generated for water phantoms and a brain case, comparing beam setups with and without the URS. Planning parameters, including spot spacing, layer spacing, and beam orientation, were varied. The effects of fractional dose and target size were also assessed. Dose and FLASH-related metrics were analyzed.</p>\n </section>\n \n <section>\n \n <h3> Results</h3>\n \n <p>The use of a URS increased the spot size, which reduced the number of required spots and energy layers but also resulted in a broader penumbra, a prolonged distal falloff, and a higher D<sub>mean</sub> in normal tissue. These effects became more pronounced with greater URS thickness. A spot spacing of 1.5 times the spot size (σ) and a layer spacing of 1.0 times the Bragg peak width (Proximal and Distal R80) improved V<sub>40Gy/s</sub>, while effectively maintaining plan quality. Beam orientations with smaller field sizes increased V<sub>40Gy/s</sub>. As the fractional dose increased, V<sub>40Gy/s</sub> also increased, reaching saturation around 25 GyRBE. Additionally, V<sub>40Gy/s</sub> improved with smaller target volumes.</p>\n </section>\n \n <section>\n \n <h3> Conclusions</h3>\n \n <p>The URS has a significant impact on plan quality, requiring a balance between normal tissue sparing and the FLASH effect in MEBP planning. Although MEBP plan is suitable for treating tumors with complex shapes, careful selection of planning parameters is critical for achieving effective FLASH treatment.</p>\n </section>\n </div>","PeriodicalId":18384,"journal":{"name":"Medical physics","volume":"52 10","pages":""},"PeriodicalIF":3.2000,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Treatment parameters consideration for universal range shifter-based multi-energy proton FLASH-RT\",\"authors\":\"Yiling Zeng, Hong Quan, Qi Zhang, Wei Wang, Xu Liu, Bin Qin, Bo Pang, Muyu Liu, Shuoyan Chen, Kunyu Yang, Yu Chang, Zhiyong Yang\",\"doi\":\"10.1002/mp.70039\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div>\\n \\n \\n <section>\\n \\n <h3> Background</h3>\\n \\n <p>Compared to conventional dose rate irradiation, ultra-high dose rate irradiation provides superior normal tissue sparing. Multi-energy proton beams combined with a universal range shifter (URS) and fast energy-switching gantry enable ultra-high dose rate delivery.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Purpose</h3>\\n \\n <p>This study investigates the effects of the URS, planning parameters, and patient selection on multi-energy Bragg peak (MEBP) proton FLASH radiotherapy (FLASH-RT) plans.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Methods</h3>\\n \\n <p>Single-field plans were generated for water phantoms and a brain case, comparing beam setups with and without the URS. Planning parameters, including spot spacing, layer spacing, and beam orientation, were varied. The effects of fractional dose and target size were also assessed. Dose and FLASH-related metrics were analyzed.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Results</h3>\\n \\n <p>The use of a URS increased the spot size, which reduced the number of required spots and energy layers but also resulted in a broader penumbra, a prolonged distal falloff, and a higher D<sub>mean</sub> in normal tissue. These effects became more pronounced with greater URS thickness. A spot spacing of 1.5 times the spot size (σ) and a layer spacing of 1.0 times the Bragg peak width (Proximal and Distal R80) improved V<sub>40Gy/s</sub>, while effectively maintaining plan quality. Beam orientations with smaller field sizes increased V<sub>40Gy/s</sub>. As the fractional dose increased, V<sub>40Gy/s</sub> also increased, reaching saturation around 25 GyRBE. Additionally, V<sub>40Gy/s</sub> improved with smaller target volumes.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Conclusions</h3>\\n \\n <p>The URS has a significant impact on plan quality, requiring a balance between normal tissue sparing and the FLASH effect in MEBP planning. 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Treatment parameters consideration for universal range shifter-based multi-energy proton FLASH-RT
Background
Compared to conventional dose rate irradiation, ultra-high dose rate irradiation provides superior normal tissue sparing. Multi-energy proton beams combined with a universal range shifter (URS) and fast energy-switching gantry enable ultra-high dose rate delivery.
Purpose
This study investigates the effects of the URS, planning parameters, and patient selection on multi-energy Bragg peak (MEBP) proton FLASH radiotherapy (FLASH-RT) plans.
Methods
Single-field plans were generated for water phantoms and a brain case, comparing beam setups with and without the URS. Planning parameters, including spot spacing, layer spacing, and beam orientation, were varied. The effects of fractional dose and target size were also assessed. Dose and FLASH-related metrics were analyzed.
Results
The use of a URS increased the spot size, which reduced the number of required spots and energy layers but also resulted in a broader penumbra, a prolonged distal falloff, and a higher Dmean in normal tissue. These effects became more pronounced with greater URS thickness. A spot spacing of 1.5 times the spot size (σ) and a layer spacing of 1.0 times the Bragg peak width (Proximal and Distal R80) improved V40Gy/s, while effectively maintaining plan quality. Beam orientations with smaller field sizes increased V40Gy/s. As the fractional dose increased, V40Gy/s also increased, reaching saturation around 25 GyRBE. Additionally, V40Gy/s improved with smaller target volumes.
Conclusions
The URS has a significant impact on plan quality, requiring a balance between normal tissue sparing and the FLASH effect in MEBP planning. Although MEBP plan is suitable for treating tumors with complex shapes, careful selection of planning parameters is critical for achieving effective FLASH treatment.
期刊介绍：
Medical Physics publishes original, high impact physics, imaging science, and engineering research that advances patient diagnosis and therapy through contributions in 1) Basic science developments with high potential for clinical translation 2) Clinical applications of cutting edge engineering and physics innovations 3) Broadly applicable and innovative clinical physics developments
Medical Physics is a journal of global scope and reach. By publishing in Medical Physics your research will reach an international, multidisciplinary audience including practicing medical physicists as well as physics- and engineering based translational scientists. We work closely with authors of promising articles to improve their quality.
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