scholarly journals Patient positioning and immobilization procedures for hybrid MR-Linac systems

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Francesco Cuccia ◽  
Filippo Alongi ◽  
Claus Belka ◽  
Luca Boldrini ◽  
Juliane Hörner-Rieber ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Radiation Oncology ◽  
Treatment Time ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Patient Positioning ◽  
Risk Identification ◽  
Linear Accelerators ◽  
Tailored Treatment

AbstractHybrid magnetic resonance (MR)-guided linear accelerators represent a new horizon in the field of radiation oncology. By harnessing the favorable combination of on-board MR-imaging with the possibility to daily recalculate the treatment plan based on real-time anatomy, the accuracy in target and organs-at-risk identification is expected to be improved, with the aim to provide the best tailored treatment. To date, two main MR-linac hybrid machines are available, Elekta Unity and Viewray MRIdian. Of note, compared to conventional linacs, these devices raise practical issues due to the positioning phase for the need to include the coil in the immobilization procedure and in order to perform the best reproducible positioning, also in light of the potentially longer treatment time. Given the relative novelty of this technology, there are few literature data regarding the procedures and the workflows for patient positioning and immobilization for MR-guided daily adaptive radiotherapy. In the present narrative review, we resume the currently available literature and provide an overview of the positioning and setup procedures for all the anatomical districts for hybrid MR-linac systems.

scholarly journals MR-Guided Hypofractionated Radiotherapy: Current Emerging Data and Promising Perspectives for Localized Prostate Cancer

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1791
Author(s):  
Francesco Cuccia ◽  
Stefanie Corradini ◽  
Rosario Mazzola ◽  
Luigi Spiazzi ◽  
Michele Rigo ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Treatment Time ◽  
Organs At Risk ◽  
Risk Identification ◽  
Life Assessment ◽  
Resonance Imaging ◽  
Few Data ◽  
Toxicity Pattern

In this review we summarize the currently available evidence about the role of hybrid machines for MR-guided radiotherapy for prostate stereotactic body radiotherapy. Given the novelty of this technology, to date few data are accessible, but they all report very promising results in terms of tolerability and preliminary clinical outcomes. Most of the studies highlight the favorable impact of on-board magnetic resonance imaging as a means to improve target and organs at risk identification with a consequent advantage in terms of dosimetric results, which is expected to relate to a more favorable toxicity pattern. Still, the longer treatment time per session may potentially affect the patient’s compliance to the treatment, although first quality of life assessment studies have reported substantial tolerability and no major impact on quality of life. Finally, in this review we hypothesize some future scenarios of further investigation, based on the possibility to explore the superior anatomy visualization and the role of daily adapted treatments provided by hybrid MR-Linacs.

scholarly journals Advantages of VMAT-IMRT technique in nasopharyngeal cancer

2016 ◽  
Vol 6 (22) ◽  
pp. 101-108
Author(s):  
Cristina Sanda ◽  
Codrut Sarafoleanu
Keyword(s):  
At Risk ◽  
Treatment Time ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Volumetric Modulated Arc Therapy ◽  
Nasopharyngeal Cancer ◽  
Intensity Modulated Radiation Therapy ◽  
Concurrent Chemotherapy ◽  
Chemotherapy Treatment ◽  
Low Incidence

Abstract BACKGROUND. Radiotherapy, associated with chemotherapy, is the main method of treatment in both early and advanced stages of nasopharyngeal carcinoma. Intensity modulated radiation therapy (IMRT) provides high doses of radiation to the primary tumor, sparing the organs at risk. Volumetric modulated arc therapy (VMAT) is one of the most promising radiation methods which produces superior target coverage, improving the protection of organs at risk and reduces treatment time. MATERIAL AND METHODS. We performed a retrospective study on 30 patients diagnosed with nasopharyngeal cancer and admitted in “Sfanta Maria” Clinical Hospital between October 2012 and December 2014. All patients have undergone VMAT-IMRT associated with induction or concurrent chemotherapy. At the end of the treatment, patients were followed up at one, three and six months, and then every six months for 2 years. RESULTS. At the end of the radio-chemotherapy treatment, 27 patients (90%) had a complete tumor and lymphatic response and 3 of them (10%) presented a partial response. At the end of the follow-up period, we observed 5 patients with recurrences, including 2 deceased. CONCLUSION. VMAT-IMRT in association with chemotherapy treatment is well tolerated by patients. The good results reflected in high rates of cured patients, the low incidence of side effects, recommend this treatment plan as an optimal indication for nasopharyngeal tumors.

The role of MR imaging in the diagnosis and treatment of anterior sacral meningocele

1988 ◽  
Vol 69 (4) ◽  
pp. 628-631 ◽  
Author(s):  
K. Stuart Lee ◽  
David J. Gower ◽  
Joe M. McWhorter ◽  
David A. Albertson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Treatment Plan ◽  
Preoperative Evaluation ◽  
Diagnostic Technique ◽  
Resonance Imaging ◽  
Content Type ◽  
Anterior Sacral Meningocele ◽  
Preoperative Diagnostic

✓ Anterior sacral meningoceles are rare. This report describes familial anterior sacral meningoceles in a father and daughter who underwent magnetic resonance imaging as part of the preoperative evaluation. Magnetic resonance imaging showed a pelvic teratoma in the daughter and confirmed the absence of abnormal tissue in the father — findings not clearly provided by ultrasound studies, myelography, or contrast-enhanced computerized tomography. It is believed that MR imaging is the most useful preoperative diagnostic technique available in establishing a treatment plan for anterior sacral meningocele.

Prediction of oligodendroglial tumor subtype and grade using perfusion weighted magnetic resonance imaging

2007 ◽  
Vol 107 (3) ◽  
pp. 600-609 ◽  
Author(s):  
Robert G. Whitmore ◽  
Jaroslaw Krejza ◽  
Gurpreet S. Kapoor ◽  
Jason Huse ◽  
John H. Woo ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Blood Volume ◽  
Tumor Grade ◽  
Grade Ii ◽  
Cytogenetic Profile ◽  
Group 2 ◽  
Oligodendroglial Neoplasms ◽  
Grade Iii ◽  
Group 1

Object Treatment of patients with oligodendrogliomas relies on histopathological grade and characteristic cytogenetic deletions of 1p and 19q, shown to predict radio- and chemosensitivity and prolonged survival. Perfusion weighted magnetic resonance (MR) imaging allows for noninvasive determination of relative tumor blood volume (rTBV) and has been used to predict the grade of astrocytic neoplasms. The aim of this study was to use perfusion weighted MR imaging to predict tumor grade and cytogenetic profile in oligodendroglial neoplasms. Methods Thirty patients with oligodendroglial neoplasms who underwent preoperative perfusion MR imaging were retrospectively identified. Tumors were classified by histopathological grade and stratified into two cytogenetic groups: 1p or 1p and 19q loss of heterozygosity (LOH) (Group 1), and 19q LOH only on intact alleles (Group 2). Tumor blood volume was calculated in relation to contralateral white matter. Multivariate logistic regression analysis was used to develop predictive models of cytogenetic profile and tumor grade. Results In World Health Organization Grade II neoplasms, the rTBV was significantly greater (p < 0.05) in Group 1 (mean 2.44, range 0.96–3.28; seven patients) compared with Group 2 (mean 1.69, range 1.27–2.08; seven patients). In Grade III neoplasms, the differences between Group 1 (mean 3.38, range 1.59–6.26; four patients) and Group 2 (mean 2.83, range 1.81–3.76; 12 patients) were not significant. The rTBV was significantly greater (p < 0.05) in Grade III neoplasms (mean 2.97, range 1.59–6.26; 16 patients) compared with Grade II neoplasms (mean 2.07, range 0.96–3.28; 14 patients). The models integrating rTBV with cytogenetic profile and grade showed prediction accuracies of 68 and 73%, respectively. Conclusions Oligodendroglial classification models derived from advanced imaging will improve the accuracy of tumor grading, provide prognostic information, and have potential to influence treatment decisions.

scholarly journals Diagnostic value of brain MR imaging and its correlation with clinical presentation and cognitive functions in idiopathic intracranial hypertension patients

2021 ◽  
Vol 57 (1) ◽  
Author(s):  
Ali Ahmed Abou Elmaaty ◽  
Carmen Ali Zarad ◽  
Tamer Ibrahim Belal ◽  
Tamer Sabry Elserafy
Keyword(s):  
Cognitive Impairment ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Intracranial Hypertension ◽  
Idiopathic Intracranial Hypertension ◽  
Brain Magnetic Resonance Imaging ◽  
Education Level ◽  
Unknown Etiology ◽  
Control Subjects ◽  
Low Education

Abstract Background Idiopathic intracranial hypertension (IIH) is a neurological disorder of unknown etiology and ambiguous pathophysiology due to cerebrospinal fluid dysregulation. This study is designed to evaluate the role of brain magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) in diagnosis of IIH, to clarify the nature and extent of cognitive deficits, and to detect if there is a correlation between radiology, clinical findings, and cognitive dysfunctions in those patients. Results The study included 34 patients and 34 age-, sex-, body mass index (BMI)-, and education-matched healthy control subjects. MR brain imaging and Montreal cognitive assessment (MoCA) test were used for both groups. MRI and MRV sensitivity for IIH diagnosis were 85.2% and 85.3% with 100% and 94.1% specificity respectively. 44.1% had cognitive impairment, memory was the most affected domain, followed by attention, abstraction, and orientation with statistically significantly lower total MoCA score (p < 0.005). Domain comparisons reveal a statistically significantly lower memory/delayed recall (p < 0.001) and abstract scores (p < 0.007) in IIH cases versus control subjects. In comparing patients with cognitive impairment (CI) versus those without CI, there were statistically significantly higher CI in low education level, presence of diplopia, hormonal contraceptive use, abnormal MRI brain, papilledema grades, BMI, and opening pressure. Conclusions Presence of more than or equal 3 MR imaging findings, bilateral transverse sinus stenosis, and less than or equal 4 combined conduit score increase the specificity and sensitivity of MRI and MRV for IIH diagnosis. IIH had detrimental effect on different cognitive domains especially when patient have low education level, diplopia, papilledema ≥ grade III, high OP ≥ 61.5 cm H2O, and BMI ≥ 34 Kg/m2 with abnormal MRI and MRV findings.

scholarly journals A Gadolinium(III) Complex Based on the Thymine Nucleobase with Properties Suitable for Magnetic Resonance Imaging

2021 ◽  
Vol 22 (9) ◽  
pp. 4586
Author(s):  
Marta Orts-Arroyo ◽  
Amadeo Ten-Esteve ◽  
Sonia Ginés-Cárdenas ◽  
Isabel Castro ◽  
Luis Martí-Bonmatí ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Lesion Detection ◽  
Resonance Imaging ◽  
X Ray Diffraction ◽  
Functional Images ◽  
High Relaxivity ◽  
Contrast Enhanced ◽  
Phantom Studies

The paramagnetic gadolinium(III) ion is used as contrast agent in magnetic resonance (MR) imaging to improve the lesion detection and characterization. It generates a signal by changing the relaxivity of protons from associated water molecules and creates a clearer physical distinction between the molecule and the surrounding tissues. New gadolinium-based contrast agents displaying larger relaxivity values and specifically targeted might provide higher resolution and better functional images. We have synthesized the gadolinium(III) complex of formula [Gd(thy)2(H2O)6](ClO4)3·2H2O (1) [thy = 5-methyl-1H-pyrimidine-2,4-dione or thymine], which is the first reported compound based on gadolinium and thymine nucleobase. 1 has been characterized through UV-vis, IR, SEM-EDAX, and single-crystal X-ray diffraction techniques, and its magnetic and relaxometric properties have been investigated by means of SQUID magnetometer and MR imaging phantom studies, respectively. On the basis of its high relaxivity values, this gadolinium(III) complex can be considered a suitable candidate for contrast-enhanced magnetic resonance imaging.

Magnetic resonance imaging—guided percutaneous fenestration of a cervical intradural cyst

2003 ◽  
Vol 99 (3) ◽  
pp. 313-315 ◽  
Author(s):  
Shinobu Takahashi ◽  
Shigehiro Morikawa ◽  
Masaaki Egawa ◽  
Yasuo Saruhashi ◽  
Yoshitaka Matsusue
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Complete Disappearance ◽  
Resonance Imaging ◽  
Content Type ◽  
Local Anesthetic Agent ◽  
Intradural Extramedullary ◽  
Severe Exercise ◽  
Exercise Induced ◽  
High Cervical

✓ The authors describe the case of a high cervical, intradural extramedullary cyst located anterior to the spinal cord in a 13-year-old boy. The lesion was fenestrated percutaneously by using real-time magnetic resonance (MR) imaging guidance and a local anesthetic agent. The patient's symptom, severe exercise-induced headache, immediately resolved after treatment. Nine months later, complete disappearance of the cyst was confirmed on MR imaging and computerized tomography myelography. Magnetic resonance imageing—guided fenestration can be considered a minimally invasive option for intradural cystic lesions.

scholarly journals Imaging features and surgery-related outcomes in intraventricular neurocysticercosis

2002 ◽  
Vol 12 (6) ◽  
pp. 1-8 ◽  
Author(s):  
Jonathan Stuart Citow ◽  
J. Patrick Johnson ◽  
Duncan Q. McBride ◽  
Mario Ammirati
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Computerized Tomography ◽  
Failure Rate ◽  
Treatment Algorithm ◽  
Parasitic Infection ◽  
Mass Effect ◽  
The United States ◽  
Imaging Features ◽  
Presenting Symptoms

Object Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system, and its prevalence is continuing to increase in the United States. The diagnosis of intraventricular NCC (IVNCC) may be difficult, and surgery frequently fails to resolve symptoms. A retrospective review of magnetic resonance (MR) imaging characteristics and surgery-related outcomes may improve management strategies of this disease. Methods The authors report the presentations, neuroimaging characteristics, surgical management, and outcomes of 30 patients with IVNCC treated over a 10-year period (mean follow-up period 4 years). Cysts were located in the lateral ventricles (five cases), the third ventricle (five cases), and the fourth ventricle (21 cases). One patient had lesions in both the lateral and fourth ventricles. Presenting symptoms were related to hydrocephalus or mass effect from the lesions. All patients underwent computerized tomography (CT) and MR imaging of the brain. Treatment consisted of shunt implantation or primary excision of an IVNCC lesion. Outcomes after operations and reoperations were evaluated in light of enhancement characteristics on MR imaging. Computerized tomography scanning demonstrated IVNCC lesions in 10% of cases, and MR revealed lesions in 100% of cases. In patients in whom gadolinium (Gd) enhancement of IVNCC lesions was demonstrated on MR imaging, the surgery-related failure rate was higher and patients required reoperation, and in those in whom gadolinium enhancement was absent the surgery-related failure rate was lower (64 and 19%, respectively; p < 0.0002). Conclusions Magnetic resonance imaging is superior to CT scanning for detecting IVNCC lesions. The absence of pericystic Gd enhancement on MR imaging is an indication for excision of the lesions. If pericystic enhancement is present, shunt surgery should be performed, and craniotomy reserved for treatment of those patients with symptomatic lesions secondary to mass effect. A treatment algorithm based on patient symptoms, cyst location, and MR imaging Gd enhancement characteristics is proposed.

Early changes measured by magnetic resonance imaging in cerebral blood flow, blood volume, and blood-brain barrier permeability following dexamethasone treatment in patients with brain tumors

1999 ◽  
Vol 90 (2) ◽  
pp. 300-305 ◽  
Author(s):  
Leif Østergaard ◽  
Fred H. Hochberg ◽  
James D. Rabinov ◽  
A. Gregory Sorensen ◽  
Michael Lev ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Brain Tumors ◽  
Mr Imaging ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Clinical Effects ◽  
Content Type ◽  
Fine Print

Object. In this study the authors assessed the early changes in brain tumor physiology associated with glucocorticoid administration. Glucocorticoids have a dramatic effect on symptoms in patients with brain tumors over a time scale ranging from minutes to a few hours. Previous studies have indicated that glucocorticoids may act either by decreasing cerebral blood volume (CBV) or blood-tumor barrier (BTB) permeability and thereby the degree of vasogenic edema.Methods. Using magnetic resonance (MR) imaging, the authors examined the acute changes in CBV, cerebral blood flow (CBF), and BTB permeability to gadolinium-diethylenetriamine pentaacetic acid after administration of dexamethasone in six patients with brain tumors. In patients with acute decreases in BTB permeability after dexamethasone administration, changes in the degree of edema were assessed using the apparent diffusion coefficient of water.Conclusions. Dexamethasone was found to cause a dramatic decrease in BTB permeability and regional CBV but no significant changes in CBF or the degree of edema. The authors found that MR imaging provides a powerful tool for investigating the pathophysiological changes associated with the clinical effects of glucocorticoids.

Sign in / Sign up

Export Citation Format

Share Document