Computational simulation of the predicted dosimetric impact of adjuvant yttrium-90 PET/CT-guided percutaneous ablation following radioembolization.

Background: Y PET/CT post-radioembolization imaging has demonstrated that the distribution of Y in a tumor can be non-uniform. Using computational modeling, we predicted the dosimetric impact of post-treatment Y PET/CT-guided percutaneous ablation of the portions of a tumor receiving the lowest absorbed dose. A cohort of fourteen patients with non-resectable liver cancer previously treated using Y radioembolization were included in this retrospective study.

Bariatric Radioembolization: A Pilot Study on Technical Feasibility and Safety in a Porcine Model.

Purpose: To evaluate feasibility of left gastric artery (LGA) yttrium-90 ((90)Y) radioembolization as potential treatment for obesity in a porcine model.

Materials And Methods: This study included 8 young female pigs (12-13 weeks, 21.8-28.

How Sensitive Is the Upper Gastrointestinal Tract to 90Y Radioembolization? A Histologic and Dosimetric Analysis in a Porcine Model.

Unlabelled: In Y radioembolization, nontarget embolization to the stomach or small bowel can result in gastrointestinal injury, a rare but difficult to manage clinical complication. However, dosimetric thresholds for toxicity to these tissues from radioembolization have never been evaluated in a controlled setting. We performed an analysis of the effect of Y radioembolization in a porcine model at different absorbed-dose endpoints.

A Microdosimetric Analysis of Absorbed Dose to Tumor as a Function of Number of Microspheres per Unit Volume in 90Y Radioembolization.

Unlabelled: Differences in maximum tolerable absorbed dose to normal liver between (90)Y radioembolization and external-beam radiation therapy have been explained by citing differences in absorbed-dose heterogeneity at the microscopic level. We investigated microscopic absorbed-dose heterogeneity in radioembolization as a function of the number of microspheres per unit volume in tumor. The goal was to determine what effect the number of microspheres may have, if any, on tumor control in (90)Y radioembolization.

The evolution of image-guided lumbosacral spine surgery.

Techniques and approaches of spinal fusion have considerably evolved since their first description in the early 1900s. The incorporation of pedicle screw constructs into lumbosacral spine surgery is among the most significant advances in the field, offering immediate stability and decreased rates of pseudarthrosis compared to previously described methods. However, early studies describing pedicle screw fixation and numerous studies thereafter have demonstrated clinically significant sequelae of inaccurate surgical fusion hardware placement.

Simulation-based educational curriculum for fluoroscopically guided lumbar puncture improves operator confidence and reduces patient dose.

Rationale And Objectives: Fluoroscopically guided lumbar puncture (FGLP) is a commonly performed procedure with increased success rates relative to bedside technique. However, FGLP also exposes both patient and staff to ionizing radiation. The purpose of this study was to determine if the use of a simulation-based FGLP training program using an original, inexpensive lumbar spine phantom could improve operator confidence and efficiency, while also reducing patient dose.

The impact of an antireflux catheter on target volume particulate distribution in liver-directed embolotherapy: a pilot study.

Purpose: To determine if there are differences in hepatic distribution of embolic particles following infusion with a standard end-hole catheter versus an antireflux microcatheter.

Materials And Methods: This prospective study included nine patients (age, 48-86 y) enrolled for treatment of hepatocellular carcinoma (n = 6), liver-dominant metastatic disease (n = 2), or intrahepatic cholangiocarcinoma (n = 1) with resin yttrium-90 ((90)Y) microspheres. Before (90)Y treatment, each patient received two same-day sequential lobar infusions of technetium 99m ((99m)Tc) macroaggregated albumin (MAA) via a conventional end-hole catheter and an antireflux microcatheter positioned at the same location.

A robust and inexpensive phantom for fluoroscopically guided lumbar puncture training.

Introduction: This report describes the creation process for an inexpensive, durable, lumbar spine phantom for use in fluoroscopically guided lumbar puncture (LP) training.

Methods: The LP phantom prototype was made from a polyvinyl chloride lumbar spine model embedded in a translucent rectangular block of commercially available thermoplastic polymer gel. Radiology residents with limited previous experience performing LP used the phantom for 20 simulated procedures to gain confidence before starting patient procedures.

Improved Accuracy of Minimally Invasive Transpedicular Screw Placement in the Lumbar Spine With 3-Dimensional Stereotactic Image Guidance: A Comparative Meta-Analysis.

Study Design: This study compares the accuracy rates of lumbar percutaneous pedicle screw placement (PPSP) using either 2-dimensional (2-D) fluoroscopic guidance or 3-dimensional (3-D) stereotactic navigation in the setting of minimally invasive spine surgery (MISS). This represents the largest single-operator study of its kind and first comprehensive review of 3-D stereotactic navigation in the setting of MISS.

Objective: To examine differences in accuracy of lumbar pedicle screw placement using 2-D fluoroscopic navigation and 3-D stereotaxis in the setting of MISS.

Reduction of patient anxiety in PET/CT imaging by improving communication between patient and technologist.

Unlabelled: Patients experience anxiety during imaging procedures because of the confined space, uncertainty about the procedure, worry about the results, and other concerns. When a patient experiences anxiety during PET/CT imaging, the quality of the scan can be affected in several ways. Current patient-technologist communication is limited in PET/CT because the technologist must be separated from the patient during the course of the imaging workflow.

A Comparison of Techniques for (90)Y PET/CT Image-Based Dosimetry Following Radioembolization with Resin Microspheres.

(90)Y PET/CT following radioembolization has recently been established as a viable diagnostic tool, capable of producing images that are both quantitative and have superior image quality than alternative (90)Y imaging modalities. Because radioembolization is assumed to be a permanent implant, it is possible to convert quantitative (90)Y PET image sets into data representative of spatial committed absorbed-dose. Multiple authors have performed this transformation using dose-point kernel (DPK) convolution to account for the transport of the high-energy (90)Y β-particles.

Radioembolization and the Dynamic Role of (90)Y PET/CT.

Before the advent of tomographic imaging, it was postulated that decay of (90) Y to the 0(+) excited state of (90)Zr may result in emission of a positron-electron pair. While the branching ratio for pair-production is small (~32 × 10(-6)), PET has been successfully used to image (90) Y in numerous recent patients and phantom studies. (90) Y PET imaging has been performed on a variety of PET/CT systems, with and without time-of-flight (TOF) and/or resolution recovery capabilities as well as on both bismuth-germanate and lutetium yttrium orthosilicate (LYSO)-based scanners.

Intraprocedural yttrium-90 positron emission tomography/CT for treatment optimization of yttrium-90 radioembolization.

Radioembolization with yttrium-90 ((90)Y) microspheres relies on delivery of appropriate treatment activity to ensure patient safety and optimize treatment efficacy. We report a case in which (90)Y positron emission tomography (PET)/computed tomography (CT) was performed to optimize treatment planning during a same-day, three-part treatment session. This treatment consisted of (i) an initial (90)Y infusion with a dosage determined using an empiric treatment planning model, (ii) quantitative (90)Y PET/CT imaging, and (iii) a secondary infusion with treatment planning based on quantitative imaging data with the goal of delivering a specific total tumor absorbed dose.

Role of positron emission tomography/computed tomography in dementia.

This article provides a clinically based review of positron emission tomography (PET) imaging for dementia. Significant advances in nuclear medicine and molecular imaging techniques have improved the understanding of the genetic and molecular processes that define neurodegenerative dementia diseases. Metabolic imaging remains constant in its ability to document neuronal loss and lost function.

Positron emission tomography/computed tomography in melanoma.

Fludeoxyglucose F 18 positron emission tomography/computed tomography (PET/CT) has been invaluable in the assessment of melanoma throughout the course of the disease. As with any modality, the studies are incomplete and more information will be gleaned as our experience progresses. Additionally, it is hoped that a newer PET agent in the pipeline will give us even greater success in the identification and subsequent treatment of melanoma.

Role of positron emission tomography/computed tomography in breast cancer.

Although positron emission tomography (PET) imaging may not be used in the diagnosis of breast cancer, the use of PET/computed tomography is imperative in all aspects of breast cancer staging, treatment, and follow-up. PET will continue to be relevant in personalized medicine because accurate tumor status will be even more critical during and after the transition from a generic metabolic agent to receptor imaging. Positron emission mammography is an imaging proposition that may have benefits in lower doses, but its use is limited without new radiopharmaceuticals.

Limitations of dual time point PET in the assessment of lung nodules with low FDG avidity.

FDG PET has long shown efficacy in the evaluation of indeterminate pulmonary nodules. More recently, the use of dual time point imaging has been looked at as a means for improving sensitivity and accuracy. While initial reports were very promising, more recent results looking specifically at pulmonary lesions with low levels of FDG avidity demonstrated limitations.

Normal organ standard uptake values in carbon-11 acetate PET imaging.

Objective: The goal of this study was to determine normal standard uptake values of carbon-11 (11C) acetate in healthy organs. By accurately determining the range of physiologic activity, abnormal focal or diffuse 11C-acetate activity can be more accurately assessed and thus improve the sensitivity and specificity of this emerging diagnostic PET agent.

Methods: We reviewed all 55 patients (mean age+/-SD 64.

Comparison of planar scintigraphy alone and with SPECT for the initial evaluation of femoral neck stress fracture.

Objective: The objective of our study was to compare the accuracy of planar scintigraphy alone versus planar scintigraphy with SPECT for the initial evaluation of femoral neck stress fractures in a young military population.

Materials And Methods: We retrospectively identified 38 patients who had undergone planar scintigraphy and 33 patients who had undergone planar scintigraphy and SPECT before MRI of the hips over a 6-month period for evaluation of suspected femoral neck fracture. Data were analyzed regarding the sensitivity and specificity of bone scanning alone and with SPECT for detecting femoral neck stress fracture and grading fractures as low grade (grades I and II) or high grade (grades III and IV).

First-pass contrast-enhanced myocardial perfusion MRI using a maximum up-slope parametric map.

Magnetic resonance first-pass perfusion imaging offers a noninvasive method for the rapid, accurate, and reproducible assessment of cardiac function without ionizing radiation. Quantitative or semiquantitative analysis of changes in signal intensity (SI) over the whole image sequence yields a more efficient analysis than direct visual inspection. In this paper, a method to generate maximum up-slope myocardial perfusion maps is presented.

Soft tissue metastases and lung cancer recurrence detected by Tc-99m depreotide scintigraphy.

A 63-year-old woman with previously treated stage I lung cancer was reexamined 5 years later for recurrence. A conventional work-up using computed tomographic scanning and transbronchial biopsy showed nothing abnormal. A Tc-99m depreotide scan, however, led to a noninvasive diagnosis of lung cancer recurrence with metastases, and it directed a noninvasive tissue diagnosis.