intensity-modulated radiation therapy

The shielding parameters can vary depending on the geometrical structure of the linear accelerators (LINAC), treatment techniques, and beam energies. Recently, the introduction of O-ring type linear accelerators is increasing. The objective of this study is to evaluate the shielding parameters of new type of linac using a dedicated program developed by us named ORSE (O-ring type Radiation therapy equipment Shielding Evaluation). The shielding evaluation was conducted for a total of four treatment rooms including Elekta Unity, Varian Halcyon, and Accuray Tomotherapy...

This study investigates the dosimetric effects of different gantry rotation angles used in volumetric modulated arc therapy (VMAT) for early glottic carcinoma. VMAT treatment plans using full-arc, half-arc, and partial-arc gantry rotation angles were generated from 22 computed tomography datasets of early-stage (T1-2N0) glottic laryngeal cancer. Dosimetric parameters associated with the planning target volume (PTV) and organs at risk (OARs), specifically the carotid arteries and thyroid, were compared. To assess the robustness of the VMAT plans, dose variations were analyzed by introducing positional shifts of 1, 3, and 5 mm from the isocenter of each plan along the superior-inferior, left-right, and anterior-posterior axes...

The current Radiotherapy (RT) technology still inevitably irradiated normal brain tissue, causing implicit radiation-induced injury. This study investigates the precise localization and the corresponding radiation dosage of brain regions susceptible to damage in nasopharyngeal carcinoma (NPC) patients following RT. Utilizing the Advanced Normalization Tools (ANTs) package, a computed tomography (CT) brain template was created in the standard Montreal Neurological Institute (MNI) space, based on 803 Chinese NPC patients (T0~T4) who underwent RT...

For locally advanced cervical cancer, the standard therapeutic approach involves concomitant chemoradiation therapy, supplemented by a brachytherapy boost. Moreover, an external beam radiotherapy (RT) boost should be considered for treating gross lymph node (LN) volumes. Two boost approaches exist with Volumetric Intensity Modulated Arc Therapy (VMAT): Sequential (SEQ) and Simultaneous Integrated Boost (SIB). This study undertakes a comprehensive dosimetric and radiobiological comparison between these two boost strategies...

OBJECTIVE:  To compare the acute toxicities of two radiation treatment techniques, intensity modulated radiation therapy (IMRT), and 3-dimensional conformal radiation therapy (3D-CRT) in localised prostate adenocarcinoma. STUDY DESIGN: Descriptive study. Place and Duration of the Study: Department of Oncology, Dr. Ziauddin Hospital, Karachi, Pakistan, from July 2016 to June 2022. METHODOLOGY: Patients with localised prostate adenocarcinoma who underwent treatment using two different advanced radiotherapy techniques i...

PURPOSE: This phase 3 trial aimed to compare the efficacy and safety of capecitabine or capecitabine plus oxaliplatin (XELOX) with those of fluorouracil plus cisplatin (PF) in definitive concurrent chemoradiotherapy (DCRT) for inoperable locally advanced esophageal squamous cell carcinoma (ESCC). METHODS: Patients were randomly assigned to receive two cycles of capecitabine, XELOX, or PF along with concurrent intensity-modulated radiation therapy. Patients in each arm were again randomly assigned to receive two cycles of consolidation chemotherapy or not...

BACKGROUND: Quality assurance (QA) of patient-specific treatment plans for intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) necessitates prior validation. However, the standard methodology exhibits deficiencies and lacks sensitivity in the analysis of positional dose distribution data, leading to difficulties in accurately identifying reasons for plan verification failure. This issue complicates and impedes the efficiency of QA tasks. PURPOSE: The primary aim of this research is to utilize deep learning algorithms for the extraction of 3D dose distribution maps and the creation of a predictive model for error classification across multiple machine models, treatment methodologies, and tumor locations...

INTRODUCTION AND AIM: Locally advanced head and neck squamous cell carcinoma (LA-Hnscc) is a true therapeutical challenge in the modern era and the scientific community is trying to face this challenge with new therapeutical strategies, including combinations of monoclonal antibodies and radiation therapy. The aim of this study is to evaluate clinical outcomes in LA-Hnscc patients unfit to receive platinum-based chemotherapy, treated with concurrent simultaneous integrated boost-intensity modulated radiotherapy (Sib-Imrt) + cetuximab (Ctx) in daily clinical practice...

BACKGROUND/AIM: To investigate the institutional experience of dose-escalated salvage whole-pelvic radiotherapy (WPRT) with the simultaneous integrated boost (SIB) technique in patients with biochemical recurrence (BCR) after radical prostatectomy for high-risk prostate cancer. PATIENTS AND METHODS: This retrospective study included 21 patients with BCR who received radical prostatectomy for high-risk prostate cancer and underwent salvage RT. Clinical target volume (CTV) of the whole pelvis (CTV56) included the prostate bed, common iliac, external iliac, internal iliac, and obturator lymph node regions...

PURPOSE: Osteoradionecrosis of the jaw (ORN) can manifest in varying severity. The aim of this study is to identify ORN risk factors and develop a novel classification to depict the severity of ORN. METHODS: Consecutive patients with head and neck cancer (HNC) treated with curative-intent intensity-modulated radiation therapy (IMRT) (≥45 Gy) from 2011 to 2017 were included. Occurrence of ORN was identified from in-house prospective dental and clinical databases and charts...

Cherenkov imaging is an ideal tool for real-time in vivo verification of a radiation therapy dose. Given that radiation is pulsed from a medical linear accelerator (LINAC) together with weak Cherenkov emissions, time-gated high-sensitivity imaging is required for robust measurements. Instead of using an expensive camera system with limited efficiency of detection in each pixel, a single-pixel imaging (SPI) approach that maintains promising sensitivity over the entire spectral band could be used to provide a low-cost and viable alternative...

BACKGROUND: For elderly patients with high-grade gliomas, 3-week hypofractionated radiotherapy (HFRT) is noninferior to standard long-course radiotherapy (LCRT). We analyzed real-world utilization of HFRT with and without systemic therapy in Medicare beneficiaries treated with RT for primary central nervous system (CNS) tumors using Centers for Medicare & Medicaid Services data. METHODS: Radiation modality, year, age (65-74, 75-84, or ≥85 years), and site of care (freestanding vs hospital-affiliated) were evaluated...

Patients with pediatric cancer receive radiotherapy to cure several types of cancer, requiring computed tomography simulation (CT sim) for precise treatment. However, there is currently no suitable framework to reduce the inherent delays in CT sim. The present study aimed to identify the underlying causes of the delays in CT sim regarding three different time periods (duration of patient admission to CT sim, diagnosis to treatment and CT sim to treatment) among patients with pediatric cancer. A total of 58 patients with pediatric cancer who received radiation therapy under anesthesia at King Abdulaziz University Hospital (Jeddah, Saudi Arabia) between 2016 and 2021 (60 months) were included in the current study...

PURPOSE: Swallow-related motion of the larynx is most significant in the cranio-caudal directions and of` short duration. Conventional target definition for radical radiation therapy includes coverage of the whole larynx. This study longitudinally examined respiration- and swallow-related laryngeal motions using cine-magnetic resonance imaging. We further analyzed the dosimetry to organs at risk by comparing 3D-conformal radiation therapy (3D-CRT), volumetric modulated arc therapy (VMAT), and intensity modulated radiation therapy (IMRT) techniques...

OBJECTIVE: To identify swallowing-related structures (SRSs) predicting post-radiotherapy dysphagia in oropharyngeal carcinoma patients. MATERIAL AND METHODS: Between September 2020 and October 2022, oropharyngeal cancer patients who had completed radiotherapy at least one year before without recurrence or residuals were selected. They underwent flexible endoscopic evaluation of swallowing (FEES) assessments and dysphagia grading. The mean radiation doses delivered to their SRSs were recalculated...

BACKGROUND: The study aims to investigate potential dosimetric benefits between non-coplanar and coplanar beam arrangements of Volumetric-Modulated Arc Therapy (VMAT) plans for liver stereotactic body radiotherapy (SBRT). METHODS: Thirteen patients who had undergone liver SBRT treatment in our department were chosen retrospectively for the study. Two sets of SBRT-VMAT plans namely, non-coplanar (NC-VMAT) and Coplanar (C-VMAT) were generated in Monaco(v5.11) planning system for Elekta Versa HD Linac using unflatten 6MV photon...

BACKGROUND: Clinical intensity modulated radiation therapy plans have been described using various complexity metrics to help identify problematic radiotherapy plans. Most previous studies related to the quantification of plan complexity and their utility have relied on institution-specific plans which can be highly variable depending on the machines, planning techniques, delivery modalities, and measurement devices used. In this work, 1723 plans treating one of only four standardized geometries were simultaneously analyzed to investigate how radiation plan complexity metrics vary across four different sets of common objectives...

PURPOSE: Pelvic recurrence is a frequent pattern of relapse for women with endometrial cancer. A randomized trial compared progression-free survival (PFS) after treatment with radiation therapy alone as compared with concurrent chemotherapy. MATERIALS AND METHODS: Between February 2008 and August 2020, 165 patients were randomly assigned 1:1 to receive either radiation treatment alone or a combination of chemotherapy and radiation treatment. The primary objective of this study was to determine whether chemoradiation therapy was more effective than radiation therapy alone at improving PFS...

IMPORTANCE: Prospective data assessing the safety of hypofractionated (40 Gy in 16 fractions) radiotherapy (RT) among patients who receive postoperative concurrent chemoradiotherapy for cervical cancer are lacking. OBJECTIVE: To evaluate the acute toxic effects of hypofractionated pelvic intensity-modulated radiotherapy (IMRT) with concurrent chemotherapy among women with cervical cancer who underwent radical hysterectomy. DESIGN, SETTING, AND PARTICIPANTS: The POHIM-CCRT (Postoperative Hypofractionated Intensity-Modulated Radiation Therapy With Concurrent Chemotherapy in Cervical Cancer) study was designed as a multicenter, phase 2 nonrandomized controlled trial that accrued and followed up patients from June 1, 2017, to February 28, 2023...

BACKGROUND: Patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy experience significant fatigue, which is frequently underestimated due to the lack of objective indicators for its evaluation. This study aimed to explore the longitudinal association between fatigue and nutrition status 1 week in advance. METHODS: From January 2021 to June 2022, a total of 105 NPC patients who received intensity-modulated radiation therapy were enrolled in the observational longitudinal study...