Effectiveness of multi-criteria optimization in combination with knowledge-based modeling in radiotherapy of left-sided breast including regional nodes.

Multi-criteria optimization (MCO) is a method that was added to treatment planning to create high-quality treatment plans. This study aimed to investigate the effectiveness of MCO in combination with knowledge-based planning (KBP) in radiotherapy for left-sided breasts, including regional nodes. Dose/volume parameters were evaluated for manual plans (MP), KBP, and KBP + MCO.

Multimodality radiomics for tumor prognosis in nasopharyngeal carcinoma.

Background: The prognosis of nasopharyngeal carcinoma (NPC) is challenging due to late-stage identification and frequently undetectable Epstein-Barr virus (EBV) DNA. Incorporating radiomic features, which quantify tumor characteristics from imaging, may enhance prognosis assessment.

Purpose: To investigate the predictive power of radiomic features on overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) in NPC.

Assessment of the Dosimetric Performance of the Mobius3D against Portal Dose Measurements in Patient-specific Quality Assurance.

Aim: The Mobius3D software addresses limitations lacking in measurement-based methods in patient-specific quality assurance (QA). The objective of this study was to validate its dosimetric performance against conventionally used portal dose measurements using gamma analysis and confidence limits.

Materials And Methods: A total of 240 patient-specific QA plans for the Varian Halcyon linear accelerator were collected.

Patient-Specific Quality Assurance in Pencil Beam Scanning by 2-Dimensional Array.

Purpose: This study aimed to determine the characteristics of 2D ionization chamber array and the confidence limits of the gamma passing rate in pencil beam scanning proton therapy.

Materials And Methods: The Varian ProBeam Compact spot-scanning system and the PTW OCTAVIUS 1500XDR array were used as a proton therapy system and detector, respectively. Our methods consisted of 2 parts: (1) the characteristics of the detector were tested and (2) patient-specific quality assurance was performed and evaluated by gamma analysis using dose-difference and distance-to-agreement criteria of 3% and 2 mm, respectively, with 123 treatment plans in head and neck, breast, chest, abdomen, and pelvic regions.

Multi-planner validation of RapidPlan knowledge-based model for volumetric modulated arc therapy in prostate cancer.

Purpose: To investigate the performance of a model-based optimization process for volumetric modulated arc therapy (VMAT) applied to prostate cancer patients with the multi-planner.

Methods And Materials: The 120 prostate plans for VMAT treatment were entered into the database system of the RapidPlan (RP) knowledge-based treatment planning. The treatment planning data for each plan was used to create and train the RP model.

Dosimetric Characteristics of Radiophotoluminescent Glass Dosimeters for Proton Beams.

Purpose: The purpose of the study was to investigate the dosimetric characteristics of radiophotoluminescent glass dosimeters (RGDs) for pencil beam scanning proton therapy. The RGD's end-to-end testing of intensity-modulated proton therapy (IMPT) plans was also evaluated.

Materials And Methods: The dosimetric characteristics of the GD-302M type glass dosimeter were studied in terms of uniformity, short-term and long-term reproducibility, stability of the magazine position readout, dose linearity in the range from 0.

Improved prediction of radiation-induced hypothyroidism in nasopharyngeal carcinoma using pre-treatment CT radiomics.

When planning radiation therapy, late effects due to the treatment should be considered. One of the most common complications of head and neck radiation therapy is hypothyroidism. Although clinical and dosimetric data are routinely used to assess the risk of hypothyroidism after radiation, the outcome is still unsatisfactory.

Validation of the Fabricated Cast Nylon Head Phantom for Stereotactic Radiosurgery End-to-End Test using Alanine Dosimeter.

Background: Stereotactic radiosurgery (SRS) is an alternative to surgery as it precisely delivers single-large doses to small tumors. Cast nylon is used in phantom due to its computed tomography (CT) number of about 56-95 HU, which is close to that of the soft tissue. Moreover, cast nylon is also more budget-friendly than the commercial phantoms.

High-dose Intensity-modulated proton therapy versus Standard-dose Intensity-modulated RadIation therapy for esophageal squamous cell carcinoma (HI-SIRI): study protocol for a randomized controlled clinical trial.

Background: Chemoradiotherapy is the standard of care for esophageal cancer as a neoadjuvant treatment before surgery, or as a definitive treatment for unresectable disease. Intensity-modulated radiotherapy (IMRT) has been considered the standard radiation technique. However, patients suffer from treatment-related toxicities, and most die from disease progression or recurrence.

Determination of Integral Depth Dose in Proton Pencil Beam Using Plane-parallel Ionization Chambers.

Purpose: This study aimed to determine the integral depth-dose curves and assess the geometric collection efficiency of different detector diameters in proton pencil beam scanning.

Materials And Methods: The Varian ProBeam Compact spot scanning system was used for this study. The integral depth-dose curves with a proton energy range of 130 to 220 MeV were acquired with 2 types of Bragg peak chambers: 34070 with 8-cm diameter and 34089 with 15-cm diameter (PTW), multi-layer ionization chamber with 12-cm diameter (Giraffe, IBA Dosimetry), and PeakFinder with 8-cm diameter (PTW).

Comparison of intensity modulated proton therapy beam configurations for treating thoracic esophageal cancer.

Background And Purpose: Specific proton-beam configurations are needed to spare organs at risk (OARs), including lungs, heart, and spinal cord, when treating esophageal squamous cell carcinoma (ESCC) in the thoracic region. This study aimed to propose new intensity-modulated proton therapy (IMPT) beam configurations and to demonstrate the benefit of IMPT compared with intensity-modulated x-ray therapy (IMXT) for treating ESCC.

Material And Methods: IMPT plans with three different beam angle configurations were generated on CT datasets of 25 ESCC patients that were treated with IMXT.

Tumor Prognostic Prediction of Nasopharyngeal Carcinoma Using CT-Based Radiomics in Non-Chinese Patients.

Purpose: We aimed to construct predictive models for the overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) for nasopharyngeal carcinoma (NPC) patients by using CT-based radiomics.

Materials And Methods: We collected data from 197 NPC patients. For each patient, radiomic features were extracted from the CT image acquired at pretreatment PyRadiomics.

Determination of field output correction factors of radiophotoluminescence glass dosimeter and CC01 ionization chamber and validation against IAEA-AAPM TRS-483 code of practice.

Purpose: To determine the field output correction factors of the radiophotoluminescence glass dosimeter (RPLGD) in parallel and perpendicular orientations with reference to CC01, the ionization chamber.

Methods: The dose to a small water volume and the sensitive volume of the RPLGD and the IBA-CC01 were determined for 6-MV, 100-cm SAD, 10-cm depth using egs_chamber user-code. The RPLGD in perpendicular and parallel orientations to the beam axis were studied.

Epigallocatechin-3-Gallate Protects Pro-Acinar Epithelia Against Salivary Gland Radiation Injury.

Antioxidant agents are promising pharmaceuticals to prevent salivary gland (SG) epithelial injury from radiotherapy and their associated irreversible dry mouth symptoms. Epigallocatechin-3-gallate (EGCG) is a well-known antioxidant that can exert growth or inhibitory biological effects in normal or pathological tissues leading to disease prevention. The effects of EGCG in the various SG epithelial compartments are poorly understood during homeostasis and upon radiation (IR) injury.

Determination of radiation dose and low-dose protocol for digital chest tomosynthesis using radiophotoluminescent (RPL) glass dosimeters.

Purpose: This study aimed to determine a low-dose protocol for digital chest tomosynthesis (DTS).

Methods: Five simulated nodules with a CT number of approximately 100 HU with size diameter of 3, 5, 8, 10, and 12 mm were inserted into an anthropomorphic chest phantom (N1 Lungman model), and then scanned by DTS system (Definium 8000) with varying tube voltage, copper filter thickness, and dose ratio. Three radiophotoluminescent (RPL) glass dosimeters, type GD-352 M with a dimension of 1.

The impact of corrected field output factors based on IAEA/AAPM code of practice on small-field dosimetry to the calculated monitor unit in eclipse™ treatment planning system.

The objective of this study was to investigate the effect of field output factors (FOFs) according to the current protocol for small-field dosimetry in conjunction to treatment planning system (TPS) commissioning. The calculated monitor unit (MU) for intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans in Eclipse™ TPS were observed. Micro ion chamber (0.

Dosimetric study of inverse-planed intensity modulated, forward-planned intensity modulated and conventional tangential techniques in breast conserving radiotherapy.

Objective: The authors present the result of a dosimetric comparison of inverse-planed intensity modulated, forward-planned intensity modulated, and conventional tangential technique in breast conserving radiotherapy.

Method And Material: The breasts (Right side: Left side = 1:1), heart, and lungs of 28 patients were contoured on all the computed tomography (CT)-slice. Three different treatment plans were created: (1) inverse IMRT (iIMRT), (2) forward IMRT (fIMRT), and (3) conventional tangential technique (CVT).

LINE-1 methylation status of endogenous DNA double-strand breaks.

DNA methylation and the repair of DNA double-strand breaks (DSBs) are important processes for maintaining genomic integrity. Although DSBs can be produced by numerous agents, they also occur spontaneously as endogenous DSBs (EDSBs). In this study, we evaluated the methylation status of EDSBs to determine if there is a connection between DNA methylation and EDSBs.

A two-year experience of implementing 3 dimensional radiation therapy and intensity-modulated radiation therapy for 925 patients in King Chulalongkorn Memorial Hospital.

Background And Objective: Three dimensional conformal radiation therapy (3D CRT) and intensity-modulated radiation therapy (IMRT) have been implemented at Department of Therapeutic Radiation and Oncology, King Chulalongkorn Memorial Hospital (KCMH) since July 2005. This is the first study in Thailand to evaluate the pattern of care and utilization of 3D CRT and IMRT for treatment in each individual cancer.

Material And Method: Between July 2005 and July 2007, 925 newly diagnosed cancer patients underwent IMRT or 3D CRT at KCMH.

Radiation dose to medical staff in interventional radiology.

Objective: The purposes of the present study were to determine the dose to medical staff in interventional radiology at different locations on the body measured by thermoluminescent dosimeter (TLD) and to relate the medical staff dose to patient dose measured by the dose-area product (DAP) meter.

Material And Method: The present study covered 42 patients in three interventional radiology procedures with three x-ray machines. Thermoluminescent dosimeters were stuck at eight positions on the radiologist's skin during the procedure.

Intensity-modulated radiation therapy in head-and-neck cancer, first report in Thailand.

Objective: This is the first report in Thailand to evaluate the efficacy of using intensity-modulated radiotherapy (IMRT) in the primary treatment of head-and-neck cancer.

Material And Method: From July 2005 to March 2006, eighteen patients with head and neck cancer were treated with IMRT, fourteen of which were nasopharyngeal cancer. The median age at diagnosis was 52 years (range 23-58 years).