Benjamin Gebauer, Sebastian Gantz, Daniela Kunath, Aswin Hoffmann, Jörg Pawelke, Felix Horst
{"title":"具有扫描质子束的商用电离室阵列在核磁共振引导质子治疗中的应用。","authors":"Benjamin Gebauer, Sebastian Gantz, Daniela Kunath, Aswin Hoffmann, Jörg Pawelke, Felix Horst","doi":"10.1002/mp.17875","DOIUrl":null,"url":null,"abstract":"<div>\n \n \n <section>\n \n <h3> Background</h3>\n \n <p>The integration of MRI-guidance and proton therapy is a current research topic. Proton therapy with the patient being placed inside an in-beam MR scanner would require the presence of its static magnetic (<span></span><math>\n <semantics>\n <msub>\n <mi>B</mi>\n <mn>0</mn>\n </msub>\n <annotation>$B_0$</annotation>\n </semantics></math>) field to be taken into account in dose calculation and treatment planning. Therefore, dosimetric tools are needed to characterize dose distributions in presence of the <span></span><math>\n <semantics>\n <msub>\n <mi>B</mi>\n <mn>0</mn>\n </msub>\n <annotation>$B_0$</annotation>\n </semantics></math> field of the MR scanner. Furthermore, patient-specific quality assurance (QA) and treatment plan verification measurements should also be performed within the magnetic field.</p>\n </section>\n \n <section>\n \n <h3> Purpose</h3>\n \n <p>In this work, the PTW Octavius 1500<span></span><math>\n <semantics>\n <msup>\n <mrow></mrow>\n <mrow>\n <mi>M</mi>\n <mi>R</mi>\n </mrow>\n </msup>\n <annotation>$^{MR}$</annotation>\n </semantics></math> ionization chamber array was characterized experimentally and tested for its suitability as a dosimetric tool for beam characterization and QA in MRI-guided proton therapy.</p>\n </section>\n \n <section>\n \n <h3> Methods</h3>\n \n <p>The dose rate response, response homogeneity and effective measurement depth of the detector were determined in experiments with scanned proton beams delivered by a horizontal beamline at OncoRay, Dresden. A patient-specific QA test including gamma analysis was performed for a realistic proton patient treatment plan at two different distances from the beam nozzle. In addition, experiments were performed in a <span></span><math>\n <semantics>\n <mrow>\n <mn>0.32</mn>\n <mspace></mspace>\n <mi>T</mi>\n </mrow>\n <annotation>$0.32 \\ \\mathrm{T}$</annotation>\n </semantics></math> in-beam MR scanner. These included measurements of square reference scanning patterns at different proton energies as well as measurements of a two-field patient treatment plan at different water equivalent depths.</p>\n </section>\n \n <section>\n \n <h3> Results</h3>\n \n <p>The dose rate response was found to be linear up to <span></span><math>\n <semantics>\n <mrow>\n <mn>80</mn>\n <mspace></mspace>\n <mtext>Gy/min</mtext>\n </mrow>\n <annotation>$80 \\ \\text{Gy/min}$</annotation>\n </semantics></math>. The effective measurement depth was determined to be <span></span><math>\n <semantics>\n <mrow>\n <mn>8.1</mn>\n <mo>±</mo>\n <mn>0.2</mn>\n <mspace></mspace>\n <mi>mm</mi>\n </mrow>\n <annotation>$8.1 \\pm 0.2 \\ \\mathrm{mm}$</annotation>\n </semantics></math>. The response homogeneity was found to be suitable for the verification of proton treatment plans. The patient-specific QA test without magnetic field was satisfactory and also the measurements inside the <span></span><math>\n <semantics>\n <mrow>\n <mn>0.32</mn>\n <mspace></mspace>\n <mi>T</mi>\n </mrow>\n <annotation>$0.32 \\ \\mathrm{T}$</annotation>\n </semantics></math> in-beam MR scanner provided reasonable results. Their comparison allowed an assessment of the magnetic field effects on the dose distributions.</p>\n </section>\n \n <section>\n \n <h3> Conclusions</h3>\n \n <p>Concluding from these tests, the Octavius 1500<span></span><math>\n <semantics>\n <msup>\n <mrow></mrow>\n <mrow>\n <mi>M</mi>\n <mi>R</mi>\n </mrow>\n </msup>\n <annotation>$^{MR}$</annotation>\n </semantics></math> was found to be suitable for use as a dosimetric tool in MRI-guided proton therapy.</p>\n </section>\n </div>","PeriodicalId":18384,"journal":{"name":"Medical physics","volume":"52 7","pages":""},"PeriodicalIF":3.2000,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mp.17875","citationCount":"0","resultStr":"{\"title\":\"Characterization of a Commercial Ionization Chamber Array With Scanned Proton Beams for Applications in MRI-Guided Proton Therapy\",\"authors\":\"Benjamin Gebauer, Sebastian Gantz, Daniela Kunath, Aswin Hoffmann, Jörg Pawelke, Felix Horst\",\"doi\":\"10.1002/mp.17875\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div>\\n \\n \\n <section>\\n \\n <h3> Background</h3>\\n \\n <p>The integration of MRI-guidance and proton therapy is a current research topic. Proton therapy with the patient being placed inside an in-beam MR scanner would require the presence of its static magnetic (<span></span><math>\\n <semantics>\\n <msub>\\n <mi>B</mi>\\n <mn>0</mn>\\n </msub>\\n <annotation>$B_0$</annotation>\\n </semantics></math>) field to be taken into account in dose calculation and treatment planning. Therefore, dosimetric tools are needed to characterize dose distributions in presence of the <span></span><math>\\n <semantics>\\n <msub>\\n <mi>B</mi>\\n <mn>0</mn>\\n </msub>\\n <annotation>$B_0$</annotation>\\n </semantics></math> field of the MR scanner. Furthermore, patient-specific quality assurance (QA) and treatment plan verification measurements should also be performed within the magnetic field.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Purpose</h3>\\n \\n <p>In this work, the PTW Octavius 1500<span></span><math>\\n <semantics>\\n <msup>\\n <mrow></mrow>\\n <mrow>\\n <mi>M</mi>\\n <mi>R</mi>\\n </mrow>\\n </msup>\\n <annotation>$^{MR}$</annotation>\\n </semantics></math> ionization chamber array was characterized experimentally and tested for its suitability as a dosimetric tool for beam characterization and QA in MRI-guided proton therapy.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Methods</h3>\\n \\n <p>The dose rate response, response homogeneity and effective measurement depth of the detector were determined in experiments with scanned proton beams delivered by a horizontal beamline at OncoRay, Dresden. 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引用次数: 0
摘要
背景：mri引导与质子治疗的结合是当前的研究课题。质子治疗将患者置于束内磁共振扫描仪中，在剂量计算和治疗计划中需要考虑其静态磁场（b0 $B_0$）的存在。因此，需要剂量学工具来表征MR扫描仪的b0 $B_0$场存在的剂量分布。此外，患者特定的质量保证（QA）和治疗计划验证测量也应在磁场内进行。目的：本文对PTW Octavius 1500 MR $^{MR}$电离室阵列进行了实验表征，并测试了其作为mri引导质子治疗中光束表征和质量保证的剂量学工具的适用性。方法：在德累斯顿OncoRay的水平束线扫描质子束实验中，测定了探测器的剂量率响应、响应均匀性和有效测量深度。在距离光束喷嘴两个不同距离处，对实际的质子患者治疗计划进行了包括伽马分析在内的患者特异性QA测试。此外，实验在0.32 T $0.32 \ \ mathm {T}$束内磁共振扫描仪上进行。其中包括测量不同质子能量下的方形参考扫描模式，以及测量不同水当量深度下的双场患者治疗计划。结果：剂量率响应在80 Gy/min以内呈线性关系。确定有效测量深度为8.1±0.2 mm $8.1 \pm 0.2 \ mathm {mm}$。发现响应均匀性适合于质子治疗方案的验证。无磁场的患者特异性QA测试令人满意，0.32 T $0.32 \ \ mathm {T}$束内磁共振扫描仪内的测量结果也很合理。他们的比较可以评估磁场对剂量分布的影响。结论：从这些试验中得出结论，Octavius 1500 MR $^{MR}$被发现适合用作mri引导质子治疗的剂量学工具。
Characterization of a Commercial Ionization Chamber Array With Scanned Proton Beams for Applications in MRI-Guided Proton Therapy
Background
The integration of MRI-guidance and proton therapy is a current research topic. Proton therapy with the patient being placed inside an in-beam MR scanner would require the presence of its static magnetic () field to be taken into account in dose calculation and treatment planning. Therefore, dosimetric tools are needed to characterize dose distributions in presence of the field of the MR scanner. Furthermore, patient-specific quality assurance (QA) and treatment plan verification measurements should also be performed within the magnetic field.
Purpose
In this work, the PTW Octavius 1500 ionization chamber array was characterized experimentally and tested for its suitability as a dosimetric tool for beam characterization and QA in MRI-guided proton therapy.
Methods
The dose rate response, response homogeneity and effective measurement depth of the detector were determined in experiments with scanned proton beams delivered by a horizontal beamline at OncoRay, Dresden. A patient-specific QA test including gamma analysis was performed for a realistic proton patient treatment plan at two different distances from the beam nozzle. In addition, experiments were performed in a in-beam MR scanner. These included measurements of square reference scanning patterns at different proton energies as well as measurements of a two-field patient treatment plan at different water equivalent depths.
Results
The dose rate response was found to be linear up to . The effective measurement depth was determined to be . The response homogeneity was found to be suitable for the verification of proton treatment plans. The patient-specific QA test without magnetic field was satisfactory and also the measurements inside the in-beam MR scanner provided reasonable results. Their comparison allowed an assessment of the magnetic field effects on the dose distributions.
Conclusions
Concluding from these tests, the Octavius 1500 was found to be suitable for use as a dosimetric tool in MRI-guided proton therapy.
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
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