Evaluation of intensity-modulated radiation therapy factors by treatment site and technique for various linear accelerators.

Purpose: The intensity-modulated radiation therapy (IMRT) factor, which is essential for calculating leakage radiation and secondary barrier thicknesses, is represented by the ratio of average monitor units (MUs) per unit dose in IMRT compared to conventional radiotherapy. The National Council on Radiation Protection and Measurements recommends a broad range of 2-10 for this factor, which can complicate its practical use. This study aims to calculate and compare the IMRT factors of Halcyon, VitalBeam, and TrueBeam based on actual MUs, offering a more accurate foundation for effective and reasonable radiation shielding determination.

Development and evaluation of a comprehensive QA phantom for image quality and geometrical accuracy in CT and CBCT for radiotherapy.

Purpose: This study presents MZ CUBE, a newly developed multipurpose phantom designed to assess both image quality and geometrical accuracy in image-guided radiotherapy.

Methods: The phantom is a 16 × 16 × 16 cm cube made of acrylonitrile butadiene styrene and designed to evaluate HU constancy, HU uniformity, spatial integrity, spatial resolution, low contrast resolution, and geometrical accuracy. Two CT simulators (Big Bore RT and Discovery RT Gen3) and two cone-beam CT (CBCT) systems (XVI and OBI) were used for verification alongside commercial phantoms (ACR 464 and CatPhan 504).

Clinical Application of Patient-Specific Bolus Based on Molding and Casting Method in Radiotherapy.

: The use of a patient-specific bolus in radiation therapy is critical for achieving precise dose delivery, particularly for irregular anatomical surfaces. Conventional boluses often suffer from poor conformity and air gaps, leading to suboptimal dose distribution. This study aimed to develop and evaluate a novel bolus fabrication method using the mold-and-casting (M&C) technique, which integrates 3D printing and flexible silicone materials to address these limitations.

Verification of Geant4-DNA step-by-step-reaction-diffusion master equation model for long-term radiolysis simulation.

Purpose: This paper describes the verification of the step-by-step-reaction-diffusion Master Equation (SBS-RDME) model, implemented in Geant4-DNA, for long-term radiolysis simulations in the Fricke dosimeter.

Methods: Scaling for reaction rate constants due to the high acidity of the Fricke solution was applied. The secondary electrons generated by gamma irradiation from Co-60 were used as the radiation source for the simulations.

Evaluation of internal scatter contribution to gonadal dose in colorectal radiotherapy.

Colorectal cancer is among the most common cancers in terms of both incidence and mortality. External beam radiotherapy is frequently used to treat colorectal cancer. In colorectal radiotherapy, the gonad is considered as an organ that must be spared owing to its radiosensitivity.

Comparative analysis of delivered and planned doses in target volumes for lung stereotactic ablative radiotherapy.

Background: Adaptive therapy has been enormously improved based on the art of generating adaptive computed tomography (ACT) from planning CT (PCT) and the on-board image used for the patient setup. Exploiting the ACT, this study evaluated the dose delivered to patients with non-small-cell lung cancer (NSCLC) patients treated with stereotactic ablative radiotherapy (SABR) and derived relationship between the delivered dose and the parameters obtained through the evaluation procedure.

Methods: SABR treatment records of 72 patients with NSCLC who were prescribed a dose of 60 Gy (D) to the 95% volume of the planning target volume (PTV) in four fractions were analysed in this retrospective study; 288 ACTs were generated by rigid and deformable registration of a PCT to a cone-beam computed tomography (CBCT) per fraction.

The impact of the new ESTRO-ACROP target volume delineation guidelines for postmastectomy radiotherapy after implant-based breast reconstruction on breast complications.

The European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) updated a new target volume delineation guideline for postmastectomy radiotherapy (PMRT) after implant-based reconstruction. This study aimed to evaluate the impact on breast complications with the new guideline compared to the conventional guidelines. In total, 308 patients who underwent PMRT after tissue expander or permanent implant insertion from 2016 to 2021 were included; 184 received PMRT by the new ESTRO-ACROP target delineation (ESTRO-T), and 124 by conventional target delineation (CONV-T).

Conversion of single-energy CT to parametric maps of dual-energy CT using convolutional neural network.

Objectives: We propose a deep learning (DL) multitask learning framework using convolutional neural network for a direct conversion of single-energy CT (SECT) to 3 different parametric maps of dual-energy CT (DECT): virtual-monochromatic image (VMI), effective atomic number (EAN), and relative electron density (RED).

Methods: We propose VMI-Net for conversion of SECT to 70, 120, and 200 keV VMIs. In addition, EAN-Net and RED-Net were also developed to convert SECT to EAN and RED.

Improvement of performance for flexible film dosimeter by incorporating additive agents.

To evaluate the reduction in energy dependence and aging effect of the lithium salt of pentacosa-10,-12-diynoic acid (LiPCDA) films with additives including aluminum oxide (AlO), propyl gallate (PG), and disodium ethylenediaminetetracetate (EDTA).. LiPCDA films exhibited energy dependence on kilovoltage (kV) and megavoltage (MV) photon energies and experienced deterioration over time.

Assessment and validation of glottic motion using cone-beam CT and real-time cine MRI.

Purpose: This study aimed to assess the margin for the planning target volume (PTV) using the Van Herk formula. We then validated the proposed margin by real-time magnetic resonance imaging (MRI).

Methods: An analysis of cone-beam computed tomography (CBCT) data from early glottic cancer patients was performed to evaluate organ motion.

Quantitative radiomics approach to assess acute radiation dermatitis in breast cancer patients.

Purpose: We applied a radiomics approach to skin surface images to objectively assess acute radiation dermatitis in patients undergoing radiotherapy for breast cancer.

Methods: A prospective cohort study of 20 patients was conducted. Skin surface images in normal, polarized, and ultraviolet (UV) modes were acquired using a skin analysis device before starting radiotherapy ('Before RT'), approximately 7 days after the first treatment ('RT D7'), on 'RT D14', and approximately 10 days after the radiotherapy ended ('After RT D10').

Novel tongue-positioning device to reduce tongue motions during radiation therapy for head and neck cancer: Geometric and dosimetric evaluation.

This study aimed to assess the performance of a tongue-positioning device in interfractional tongue position reproducibility by cone-beam computed tomography (CBCT). Fifty-two patients treated with radiation therapy (RT) while using a tongue positioning device were included in the study. All patients were treated with 28 or 30 fractions using the volumetric modulated arc therapy technique.

Extension of matRad with a modified microdosimetric kinetic model for carbon ion treatment planning: Comparison with Monte Carlo calculation.

Background: Treatment planning is essential for in silico particle therapy studies. matRad is an open-source research treatment planning system (TPS) based on the local effect model, which is a type of relative biological effectiveness (RBE) model.

Purpose: This study aims to implement a microdosimetric kinetic model (MKM) in matRad and develop an automation algorithm for Monte Carlo (MC) dose recalculation using the TOPAS code.

Evaluation of initial patient setup methods for breast cancer between surface-guided radiation therapy and laser alignment based on skin marking in the Halcyon system.

Background: This study was conducted to evaluate the efficiency and accuracy of the daily patient setup for breast cancer patients by applying surface-guided radiation therapy (SGRT) using the Halcyon system instead of conventional laser alignment based on the skin marking method.

Methods And Materials: We retrospectively investigated 228 treatment fractions using two different initial patient setup methods. The accuracy of the residual rotational error of the SGRT system was evaluated by using an in-house breast phantom.

Short-term and long-term effects of noninvasive cardiac radioablation for ventricular tachycardia: A single-center case series.

Background: Noninvasive cardiac radioablation is reported to be effective and safe for the treatment of ventricular tachycardia (VT).

Objective: This study aimed to analyze the acute and long-term effects of VT radioablation.

Methods: Patients with intractable VT or premature ventricular contraction (PVC)-induced cardiomyopathy were included in this study and treated using a single-fraction 25-Gy dose of cardiac radioablation.

Feasibility and safety of neck level IB-sparing radiotherapy in nasopharyngeal cancer: a long-term single institution analysis.

Purpose: Nasopharyngeal cancer (NPC) has a higher prevalence of regional nodal metastasis than other head and neck cancers; however, level IB lymph node involvement is rare. We evaluated the safety and feasibility of level IB-sparing radiotherapy (RT) for NPC patients.

Materials And Methods: We retrospectively reviewed 236 patients with NPC who underwent definitive intensity-modulated RT with or without chemotherapy between 2004 and 2018.

Image-Guided Versus Conventional Brachytherapy for Locally Advanced Cervical Cancer: Experience of Single Institution with the Same Practitioner and Time Period.

Purpose: This study aimed to compare treatment outcomes and toxicity profile between imaged-guided brachytherapy (IGBT) versus conventional brachytherapy (CBT) performed by the same practitioner during the same time period.

Materials And Methods: Medical records of 104 eligible patients who underwent brachytherapy for locally advanced cervical cancer were retrospectively reviewed. Fifty patients (48.

Performance evaluation of a visual guidance patient-controlled respiratory gating system for respiratory-gated magnetic-resonance image-guided radiation therapy.

The performance of a visual guidance patient-controlled (VG-PC) respiratory gating system for magnetic-resonance (MR) image-guided radiation therapy (MR-IGRT) was evaluated through a clinical trial of patients with either lung or liver cancer. Patients can voluntarily control their respiration utilizing the VG-PC respiratory gating system. The system enables patients to view near-real-time cine planar MR images projected inside the bore of MR-IGRT systems or an external screen.

Development of an anthropomorphic multimodality pelvic phantom for quantitative evaluation of a deep-learning-based synthetic computed tomography generation technique.

Purpose: The objective of this study was to fabricate an anthropomorphic multimodality pelvic phantom to evaluate a deep-learning-based synthetic computed tomography (CT) algorithm for magnetic resonance (MR)-only radiotherapy.

Methods: Polyurethane-based and silicone-based materials with various silicone oil concentrations were scanned using 0.35 T MR and CT scanner to determine the tissue surrogate.

Scanning methodology for contact lens-type ocular in vivo dosimeter (CLOD) dosimetry applying a silicone material.

Purpose: Contact lens-type ocular in vivo dosimeters (CLODs) were recently developed as the first in vivo dosimeter that can be worn directly on the eye to measure the dose delivered to the lens during radiotherapy. However, it has an inherent uncertainty because of its curved shape. Newton's ring effect inevitably occurs because the spacing between the glass window and the active layer is not constant.

3D star shot analysis using MAGAT gel dosimeter for integrated imaging and radiation isocenter verification of MR-Linac system.

Purpose: This study aims to investigate a star shot analysis using a three-dimensional (3D) gel dosimeter for the imaging and radiation isocenter verification of a magnetic resonance linear accelerator (MR-Linac).

Methods: A mixture of methacrylic acid, gelatin, and tetrakis (hydroxymethyl) phosphonium chloride, called MAGAT gel, was fabricated. One MAGAT gel for each Linac and MR-Linac was irradiated under six gantry angles.

Comparison of treatment plans between static jaw and jaw tracking techniques in postmastectomy intensity-modulated radiation therapy.

This study reports a dosimetric comparison between treatment plans using static jaw and jaw tracking techniques in intensity-modulated radiation therapy (IMRT) for postmastectomy radiation therapy (PMRT). Seventeen patients treated for left-sided breast cancer with implant-based reconstruction were subjected to IMRT plans. Another group of 22 patients treated for left-sided breast cancer without reconstruction was also subjected to IMRT plans.