Image Guided Radiotherapy

PURPOSE: We evaluate the performance of a deformable image registration (DIR) software package in registering abdominal magnetic resonance images (MRIs) and then develop a mechanical modeling method to mitigate detected DIR uncertainties. MATERIALS AND METHODS: Three evaluation metrics, namely mean displacement to agreement (MDA), DICE similarity coefficient (DSC), and standard deviation of Jacobian determinants (STD-JD), are used to assess the multi-modality (MM), contour-consistency (CC), and image-intensity (II)-based DIR algorithms in the MIM software package, as well as an in-house developed, contour matching-based finite element method (CM-FEM)...

BACKGROUND: The aim of this multi-institutional phase II study was to confirm the safety and the potential efficacy of moderately hypofractionated intensity-modulated radiotherapy (IMRT) with prostate-based image-guidance for Japanese patients. METHODS: Patients with low- or intermediate-risk localized prostate cancer were eligible. Patients with a part of high risk (having only one of the following factors, cT3a, 20 < PSA ≤ 30, or GS = 8 or 9) were also included...

Since 2010, there has been little published data on the state of equipment and infrastructure in veterinary radiation oncology clinical practice. These data are important not only to identify the status and use of technology within the veterinary radiation oncology community but also to help identify the extent of medical physics support. The purpose of our study is to report findings from a survey of veterinary radiation oncologists in the USA, Canada, and select centers outside of North America in 2022. A 40-question survey covering topics such as type of radiotherapy equipment, techniques offered, treatment planning systems and dose calculation algorithms, special techniques, board-certified radiation oncologists and residents, and extent of medical physics support was distributed through an online survey tool...

The American Association of Physicists in Medicine (AAPM) recently published the report of Task Group (TG) 302, which provides recommendations on acceptance, commissioning, and ongoing routine quality assurance (QA) for surface-guided radiation therapy (SGRT) systems. One of the recommended monthly QA tests is a dynamic localization accuracy test. This work aimed to develop an automated procedure for monthly SGRT dynamic localization QA. An anthropomorphic head phantom was rigidly attached to the 6-dof couch of a TrueBeam linac...

BACKGROUND AND PURPOSE: This study evaluated long-term efficacy, safety, and changes in quality of life (QOL) of patients after image-guided proton therapy (IGPT) for operable stage I non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: This single-institutional prospective phase 2 study enrolled patients with operable histologically confirmed stage IA or IB NSCLC (7th edition of UICC). The prescribed dose was 66 Gy relative biological effectiveness equivalents (GyRBE) in 10 fractions for peripheral lesions, or 72...

Superparamagnetic iron oxide nanoparticles (SPION) have attracted great attention not only for therapeutic applications but also as an alternative magnetic resonance imaging (MRI) contrast agent that helps visualize liver tumors during MRI-guided stereotactic body radiotherapy (SBRT). SPION can provide functional imaging of liver parenchyma based upon its uptake by the hepatic resident macrophages or Kupffer cells with a relative enhancement of malignant tumors that lack Kupffer cells. However, the radiomodulating properties of SPION on liver macrophages are not known...

To develop ultrasound-guided radiotherapy, we proposed an assistant structure with embedded markers along with a novel alternative method, the Aligned Peak Response (APR) method, to alter the conventional delay-and-sum (DAS) beamformer for reconstructing ultrasound images obtained from a flexible array. We simulated imaging targets in Field-II using point target phantoms with point targets at different locations. In the experimental phantom ultrasound images, image RF data were acquired with a flexible transducer with in-house assistant structures embedded with needle targets for testing the accuracy of the APR method...

PURPOSE/OBJECTIVE: To determine the impact of a MR-based contouring atlas for male pelvis radiotherapy delineation on inter-observer variation to support radiographer led real-time magnetic resonance image guided adaptive radiotherapy (MRgART). MATERIAL/METHODS: Eight RTTs contoured 25 MR images in the Monaco treatment planning system (Monaco 5.40.01), from 5 patients. The prostate, seminal vesicles, bladder, and rectum were delineated before and after the introduction of an atlas developed through multi-disciplinary consensus...

INTRODUCTION: Adapting radiotherapy services with workforce innovation using skills-mix or task-shifting optimises resources, supporting current and future demands. Advanced practitioners (APs) work at a different level of practice (beyond initial registration) across four pillars: clinical practice, leadership and management, education, and research. There is limited cross-country research on the advanced therapeutic radiographers/radiation therapists (TR/RTTs), particularly in Europe...

BACKGROUND: Volumetric modulated arc therapy (VMAT) guided by ultrasound is a novel radiation therapy technique that facilitates the delineation of the tumor target area under image guidance, enhancing the precision of radiation therapy and maximizing the protection of surrounding tissues. OBJECTIVE: The objective of this paper is to investigate the effectiveness of VMAT under ultrasonic guidance for cervical cancer patients and its impact on radiotherapy dosage and prognosis...

PURPOSE: Magnetic resonance imaging (MRI)-guided radiotherapy enables adaptive treatment plans based on daily anatomical changes and accurate organ visualization. However, the bias field artifact can compromise image quality, affecting diagnostic accuracy and quantitative analyses. This study aims to assess the impact of bias field correction on 0.35 T pelvis MRIs by evaluating clinical anatomy visualization and generative adversarial network (GAN) auto-segmentation performance. MATERIALS AND METHODS: 3D simulation MRIs from 60 prostate cancer patients treated on MR-Linac (0...

INTRODUCTION: Acoustic noise from magnetic resonance imaging (MRI) can cause hearing loss and needs to be mitigated to ensure the safety of patients and personnel. Capturing MR personnel's insights is crucial for guiding the development and future applications of noise-reduction technology. This study aimed to explore how MR radiographers manage acoustic noise in clinical MR settings. METHODS: Using a qualitative design, we conducted semi-structured individual interviews with fifteen MR radiographers from fifteen hospitals around Sweden...

Intensity-based 2D/3D registration using kilo-voltage (kV) and mega-voltage (MV) on-board imaging is a promising approach for real-time tumor motion tracking. So far, the performance of the kV images as well as kV-MV image pairs for 2D/3D registration using only one gantry angle (in anterior-posterior (AP) direction) has been investigated on patient data. In stereotactic body radiation therapy (SBRT), however, various gantry angles are typically used. This study attempts to answer the question of whether automatic 2D/3D registration is possible using kV images as well as kV-MV image pairs for gantry angles other than the AP direction...

This series introduces the clinical management of difficult-to-treat non-melanoma skin cancers (NMSCs) through a multidisciplinary approach, emphasizing the integration of dermoscopy and Ultra high-frequency ultrasound (UHFUS) for accurate diagnosis and treatment planning, particularly in cases referred for radiotherapy (RT). Dermoscopy aids in diagnosing both pigmented and non-pigmented skin lesions, guiding treatment margins and reducing the benign-to-malignant biopsy ratio. UHFUS provides valuable insights into tumor size, depth, and vascularity, complementing clinical evaluations and assisting in RT planning...

INTRODUCTION: Invisible ink tattoos (IITs) avoid cosmetic permanence of visible ink tattoos (VITs) while serving as more reliable landmarks for radiation setup than tattooless setups. This trial evaluated patient-reported preference and feasibility of IIT implementation. METHODS AND MATERIALS: In an IRB-approved, single institution, prospective trial, patients receiving proton therapy underwent IIT-based treatment setup. A survey tool assessed patient preference on tattoos using a Likert scale...

BACKGROUND: Rwanda has aimed to rebuild its health care system since the Rwandan genocide against the Tutsis in 1994, though one of the challenges has been a scarcity of radiologic resources. OBJECTIVE: To assess the location and accessibility of radiologic facilities in Rwanda using geospatial mapping and population-based data. METHODS: A cross-sectional study was conducted in May 2023 using location and radiologic modality data provided by the Department of Radiology at the University Teaching Hospital of Kigali and the WorldPop database, a publicly available database providing open-access geospatial population data...

BACKGROUND: MRI-Linac systems enable daily diffusion-weighed imaging (DWI) MRI scans for assessing glioblastoma tumor changes with radiotherapy treatment. PURPOSE: Our study assessed the image quality of echoplanar imaging (EPI)-DWI scans compared with turbo spin echo (TSE)-DWI scans at 0.35 Tesla (T) and compared the apparent diffusion coefficient (ADC) values and distortion of EPI-DWI on 0.35 T MRI-Linac compared to high-field diagnostic MRI scanners. METHODS: The calibrated National Institute of Standards and Technology (NIST)/Quantitative Imaging Biomarkers Alliance (QIBA) Diffusion Phantom was scanned on a 0...

Lymphoma represent the third most common malignant disease in childhood and adolescence. They are divided into pediatric Hodgkin lymphoma (P-HL) and pediatric non-Hodgkin lymphoma (P-NHL). In P-HL, excellent cure rates are achieved through combined modality treatment using chemotherapy and radiotherapy. For more than 20 years, FDG-PET has been an integral part of the treatment and guides its intensity through improved staging and precise assessment of chemotherapy response. In P-NHL, good cure rates are achieved with chemotherapy alone...

BACKGROUND: Due to superior image quality and daily adaptive planning, MR-guided stereotactic body radiation therapy (MRgSBRT) has the potential to further widen the therapeutic window in radiotherapy of localized prostate cancer. This study reports on acute toxicity rates and patient-reported outcomes after MR-guided adaptive ultrahypofractionated radiotherapy for localized prostate cancer within the prospective, multicenter phase II SMILE trial. MATERIALS AND METHODS: A total of 69 patients with localized prostate cancer underwent MRgSBRT with daily online plan adaptation...

PET-driven SBRT plus pembrolizumab as first-line therapy against pleomorphic Pancoast cancer appears beneficial, probably due to high equivalent doses of SBRT on photopenic necrotic core and synergic immune system stimulation of immunoradiotherapy.