Nonradiographic Imaging Research Articles

The Spectrum of Rib Neoplasms in Adults: A Practical Approach and Multimodal Imaging Review.

OBJECTIVE. Adult neoplasms of the ribs are a heterogeneous group consisting of both benign and aggressive entities. Rib neoplasms have a variety of overlapping imaging features, with much of the imaging data disjointed across the musculoskeletal, thoracic, and oncologic imaging literature. Arrival at accurate diagnosis can therefore be quite challenging. This article consolidates this information and introduces the reader to an algorithmic approach to rib lesion evaluation based on imaging. CONCLUSION. Rib neoplasms are a diverse group of benign and malignant entities, which often makes determining an accurate diagnosis challenging. Evaluation requires a multipronged approach that incorporates radiographic imaging features, nonradiographic imaging findings, lesion location, and clinical data.

An ultrasound based platform for image-guided radiotherapy in canine bladder cancer patients.

Background and purposeUltrasound (US) is a non-invasive, non-radiographic imaging technique with high spatial and temporal resolution that can be used for localizing soft-tissue structures and tumors in real-time during radiotherapy (RT) (inter- and intra-fraction). A comprehensive approach incorporating an in-house 3D-US system within RT is presented. This system is easier to adopt into existing treatment protocols than current US based systems, with the aim of providing millimeter intra-fraction alignment errors and sensitivity to track intra-fraction bladder movement.Materials and methodsAn in-house integrated US manipulator and platform was designed to relate the computed tomographic (CT) scanner, 3D-US and linear accelerator coordinate systems. An agar-based phantom with measured speed of sound and densities consistent with tissues surrounding the bladder was rotated (0–45°) and translated (up to 55 mm) relative to the US and CT coordinate systems to validate this device. After acquiring and integrating CT and US images into the treatment planning system, US-to-US and US-to-CT images were co-registered to re-align the phantom relative to the linear accelerator.ResultsStatistical errors from US-to-US registrations for various patient orientations ranged from 0.1 to 1.7 mm for x, y, and z translation components, and 0.0–1.1° for rotational components. Statistical errors from US-to-CT registrations were 0.3–1.2 mm for the x, y and z translational components and 0.1–2.5° for the rotational components.ConclusionsAn ultrasound-based platform was designed, constructed and tested on a CT/US tissue-equivalent phantom to track bladder displacement with a statistical uncertainty to correct and track inter- and intra-fractional displacements of the bladder during radiation treatments.

WE‐DE‐BRA‐03: Construction of An Ultrasound Guidance Platform for Image‐Guided Radiotherapy with the Intent to Treat Transitional Cell Carcinoma

Purpose:Ultrasound (US) is a noninvasive, nonradiographic imaging technique with high spatial and temporal resolution that can be used for localizing soft‐tissue structures and tumors in real‐time during radiotherapy (inter‐ and intra‐fraction). A detailed methodology integrating 3D‐US within RT is presented. This method is easier to adopt into current treatment protocol than current US based systems and reduces user variability for image acquisition, thus eliminating transducer induced changes that limit CT planning system.Methods:We designed an in‐house integrated US manipulator and platform to relate CT, 3D‐US and linear accelerator coordinate systems. To validate the platform, an agar‐based phantom with measured densities and speed‐of‐sound consistent with tissues surrounding the bladder, was rotated (0–45°) resulting in translations (up to 55mm) relative to the CT and US coordinate systems. After acquiring and integrating CT and US images into the treatment planning system, US‐to‐US and US‐to‐CT images were co‐registered to re‐align the phantom relative to the linear accelerator. Errors in the transformation matrix components were calculate to determine precision of this method under different patient positions.Results:Statistical errors from US‐US registrations for different patient orientations ranged from 0.06–1.66mm for x, y, and z translational components, and 0.00–1.05° for rotational components. Statistical errors from US‐CT registrations were 0.23–1.18mm for the x, y and z translational components, and 0.08–2.52° for the rotational components.Conclusion:Based on our result, this is consistent with currently used techniques for positioning prostate patients if couch re‐positioning is less than a 5 degree rotation. We are now testing this on a dog patient to obtain both inter and intra‐fractional positional errors. Additional design considerations include the future use of ultrasound‐based functionality (photoacoustics, radioacoustics, Doppler) to monitor blood flow and hypoxia and/or in‐vivo dosimetry for applications in other therapeutic techniques, such as hyperthermia, anti‐angiogenesis, and particle therapy.

SU-E-J-82: Evaluation of the Spatial Reproducibility and Temporal Drift of the CRAD CatalystHD System

Introduction: With the implementation of new nonradiographic imaging technologies, system performance characterization is crucial prior to clinical implementation.In this study, the short-term static, spatial reproducibility and temporal drift of the CatalystHD 3-camera nonradiographic imaging system were evaluated. Methods: Using the CatalystHD Daily Check phantom aligned to the room lasers, both the spatial reproducibility and temporal drift were analyzed in the treatment room with low ambient light (12.65lx)and full light (236.25lx).For temporal drift, measurements were acquired every 5min after cold initialization for 60min without altering the position of the phantom.Prior to the initial measurement, cameras were off for a minimum of 24hours.For spatial reproducibility, a series of 30 sequential measurements were acquired over a 25min period after the system had been on for more than 3 hours without adjusting the Daily Check phantom.For both tests, spatial location of the phantom determined by the CatalystHD system was recorded Results: For temporal drift, total displacement vectors and equilibrium times were calculated for each camera.Displacement vectors were normalized to a value long after equilibrium had been achieved.For the middle camera in low light, ΔX,ΔY,ΔZ,Δ3D were 0.2,0.8,0.1and 0.9 mm, respectively.For full light, ΔX,ΔY,ΔZ,Δ3D were 0.2,1.0,0.1and 1.1 mm, respectively.Both the left and right camera responded similarly.The equilibrium time in low light was 35,45,and 45 minutes for the left, middle and right cameras, respectively, while in full light, they were 30,45,and 40 minutes.For spatial reproducibility in low light, the STD of the recorded locations were 0.04,0.02,0.03mm for the left, middle and right cameras, respectively.For full light, deviations of 0.03,0.02and 0.03 were recorded. Maximum recorded range for any deviation was 0.14mm—below system specification of 0.2mm. Conclusion: A study was performed to assess the spatial reproducibility and temporal drift of the CatalystHD as recommended by TG-147 for nonradiographic imaging systems.An overall warmup time of at least 45 minutes is recommended prior to use. This work was funded in part by the Cancer Prevention Research Institute of Texas Pre doctoral fellowship training grant (RP140105) to Dennis N. Stanley M.Sc.

Deficit Reduction Act: Effects on Utilization of Noninvasive Musculoskeletal Imaging

To ascertain the effects of the payment reductions in the Deficit Reduction Act (DRA), which affected only in-office imaging, on the utilization of noninvasive musculoskeletal imaging. This study of nonidentifiable aggregate data did not require institutional review board approval. Medicare Part B Physician/Supplier Procedure Summary Files for 2004, 2006, and 2008 were used. By using descriptive statistics and weighted linear regression, all 111 relevant procedure codes were evaluated to measure the effect of the DRA's payment reductions on change in utilization growth rate between the pre-DRA (2004-2006) and post-DRA (2006-2008) periods. Overall, between the pre-DRA and post-DRA periods, the type of imaging studied demonstrated a 2% deceleration (reduction in per capita utilization growth rate) in the office and a 0.7% deceleration in the outpatient hospital setting. However, nonradiologist and radiologist utilization were both still growing, particularly for nonradiographic imaging. In the office, for both nonradiologists and radiologists, larger DRA payment reductions were associated with greater deceleration; deceleration was approximately 0.2% greater for each additional 1% of reimbursement reduction. There was no payment-reduction-size-related acceleration in the outpatient setting. The growth rate of in-office noninvasive musculoskeletal imaging performed by nonradiologists and the growth rate of this type of imaging being referred to radiologists decreased in the period following the implementation of the DRA. Nonetheless, after the DRA, in-office nonradiographic noninvasive musculoskeletal imaging performed by nonradiologists was still growing much more rapidly than that performed by radiologists.

Gastrointestinal Imaging in Pediatrics

The second edition of this book represents an expanded and updated version of the original edition. After several preliminary chapters dealing with examination techniques and indications, the book is arranged by anatomic areas from the pharynx to the colon. Each section deals with the normal and pathologic entities affecting that area, with a discussion given on the etiology, significance, and pathology. Ample and excellent radiographic illustrations abound and are often supplemented with line drawings and diagrams. The experience of the authors is included with statistics from the literature. Although there are few examples of nonradiographic imaging within the anatomically oriented chapters, this deficiency is corrected by the inclusion of chapters on computed tomography, angiography, nuclear medicine, and ultrasound. Each is outstanding, although one wishes more of this type of material could have been included throughout the body of the book. The references are numerous and up to date. They are