Verification of linear energy transfer optimized carbon-ion radiotherapy.

Linear energy transfer (LET) verification was conducted using a silicon-on-insulator (SOI) microdosimeter during the commissioning of LET-optimized carbon-ion radiotherapy (CIRT). This advanced treatment technique is expected to improve local control rates, especially in hypoxic tumors.An SOI microdosimeter with a cylindrical sensitive volume of 30m diameter and 5m thickness was used.

Three-dimensional Patient-specific Quality Assurance Using Beam Delivery Log Data for Pencil Beam Scanning Carbon-ion Radiotherapy.

Background/aim: In the pencil beam scanning carbon-ion radiotherapy, spot positions are arranged in three dimensions throughout the entire target region. Therefore, dose deviations can occur due to spot position errors in the target. However, performing three-dimensional measurements for routine patient-specific quality assurance (PSQA) is difficult because a simple measurement method has not been established.

Study of Simultaneous Integrated Boost Carbon-Ion Radiotherapy for Locally Advanced Pancreatic Cancer.

Background/aim: Carbon-ion radiotherapy (CiRT) has been used for the treatment of locally advanced pancreatic cancer (LAPC) with uniform dose plan. The aim of the present study is to investigate the effectiveness of a simultaneous integrated boost (SIB) technique with scanned CiRT against LAPC.

Materials And Methods: Data of 21 patients with LAPC were used to compare two treatment planning approaches: a conventional uniform dose approach and a SIB approach.

[Safety Analysis Using Event Tree Analysis for Multi-Ion Therapy].

At the National Institutes for Quantum Science and Technology (QST), a multi-ion therapy using helium, carbon, oxygen, and neon ions has been studied for charged particle therapy with more optimal biological effects. To make multi-ion therapy clinically feasible, a new treatment system was developed to realize the changes of the ion species in each irradiation using the Heavy Ion Medial Accelerator in Chiba (HIMAC). Since radiation therapy is safety-critical, it is necessary to construct a safety system that includes multiple safety barriers in the new treatment system for multi-ion therapy and to perform a safety analysis for the prevention of serious accidents.

End-to-end dosimetry audit for three-dimensional image-guided brachytherapy for cervical cancer.

Background: End-to-end dosimetry audit for brachytherapy is challenging due to the steep dose gradient. However, it is an efficient method to detect unintended errors in actual clinical practice.

Purpose: We aimed to develop an on-site end-to-end test phantom for three-dimensional image-guided brachytherapy (IGBT) for cervical cancer.

Clinical dose assessment for scanned carbon-ion radiotherapy using linear energy transfer measurements and Monte Carlo simulations.

. Dosimetric commissioning of treatment planning systems (TPS) focuses on validating the agreement of the physical dose with experimental data. For carbon-ion radiotherapy, the commissioning of the relative biological effectiveness (RBE) is necessary to predict the clinical outcome based on the radiation quality of the mixed radiation field.

Microdosimetric investigation for multi-ion therapy by means of silicon on insulator (SOI) microdosimeter.

Ion radiotherapy with protons or carbon ions is one of the most advanced clinical methods for cancer treatment. To further improve the local tumor control, ion radiotherapy using multiple ion species has been investigated. Due to complexity of dose distributions delivered by multi-ion therapy in a tumor, a validation strategy for the planned treatment efficacy must be established that can be potentially used in the quality assurance (QA) protocol for the multi-ion treatment plans.

Dose response of a radiophotoluminescent glass dosimeter for TomoTherapy, CyberKnife, and flattening-filter-free linear accelerator output measurements in dosimetry audit.

Purpose: We experimentally determined the radiophotoluminescent glass dosimeter (RPLD) dose responses for TomoTherapy, CyberKnife, and flattening-filter-free (FFF) linear accelerator (linac) outputs for dosimetry audits in Japan.

Methods: A custom-made solid phantom with a narrow central-axis spacing of three RPLD elements was used for output measurement to minimise the dose-gradient effect of the non-flattening filter beams. For RPLD dose estimation, we used the ISO 22127 formalism.

Application of lung substitute material as ripple filter for multi-ion therapy with helium-, carbon-, oxygen-, and neon-ion beams.

A development project for hypo-fractionated multi-ion therapy has been initiated at the National Institute of Radiological Sciences in Japan. In the treatment, helium, carbon, oxygen, and neon ions will be used as primary beams with pencil beam scanning. A ripple filter (RiFi), consisting of a thin plastic or aluminum plate with a fine periodic ridge and groove structure, has been used to broaden the Bragg peak of heavy-ion beams in the beam direction.

Feasibility study of using Stereotactic Field Diode for field output factors measurement and evaluating three new detectors for small field relative dosimetry of 6 and 10 MV photon beams.

This study assesses the feasibility of using stereotactic field diode (SFD) as an alternate to gaf chromic films for field output factor (FF) measurement and further evaluating three new detectors for small field dosimetry. Varian 21EX linear accelerator was used to generate 6 and 10 MV beams of nominal square fields ranging from 0.5 × 0.