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Objectives Several plaque and lesion characteristics have been associated with an increased risk for procedural stroke during or shortly after carotid artery stenting (CAS). While technical advancements in stent design and cerebral protection devices (CPD) may help reduce the procedural stroke risk, and anatomy remains important, tailoring stenting procedures according to plaque and lesion characteristics might be a useful strategy in reducing stroke associated with CAS. In this descriptive report of the ongoing Asymptomatic Carotid Surgery Trial-2 (ACST-2), it was assessed whether choice for stent and use or type of CPD was influenced by plaque and lesion characteristics. Materials and methods Trial patients who underwent CAS between 2008 and 2015 were included in this study. Chi-square statistics were used to study the effects of plaque echolucency, ipsilateral preocclusive disease (90–99%), and contralateral high-grade stenosis (>50%) or occlusion of the carotid artery on interventionalists' choice for stent and CPD. Differences in treatment preference between specialties were also analysed. Results In this study, 831 patients from 88 ACST-2 centres were included. Almost all procedures were performed by either interventional radiologists (50%) or vascular surgeons (45%). Plaque echolucency, ipsilateral preocclusive disease (90–99%), and significant contralateral stenosis (>50%) or occlusion did not affect the choice of stent or either the use of cerebral protection and type of CPD employed (i.e., filter/flow reversal). Vascular surgeons used a CPD significantly more often than interventional radiologists (98.6% vs. 76.3%; p < .001), but this choice did not appear to be dependent on patient characteristics. Conclusions In ACST-2, plaque characteristics and severity of stenosis did not primarily determine interventionalists' choice of stent or use or type of CPD, suggesting that other factors, such as vascular anatomy or personal and centre preference, may be more important. Stent and CPD use was highly heterogeneous among participating European centres.

Purpose: Deadtime-count-loss (DTloss) correction using monitor source (MS) requires: 1) uniform fractional DTloss across FOV, 2) high statistics MS images both with & without the object. The aims are validating condition 1 and developing a practical protocol that satisfies conditions 2 with minimal additional study duration.Methods and Materials: SPECT images of non-uniform phantoms (4GBq 99mTc) along with MS (20MBq 99mTc) attached to each detector were acquired multiple times over 48 hours in photopeak and scatter energy window (EW) using Siemens-SymbiaS and GE-D670. Planar images of the MS alone were acquired. Photopeak counts for the MS ROIs were > 100kcts. Fractional DTloss uniformity across the FOV was evaluated by correlating count rates in different ROIs on projection images at different DTloss levels. The correction factor for each SPECT projection at every time point was calculated as the ratio of time-corrected MS count rates with & without the phantom.The DTloss-corrected projections for each SPECT acquisition were decay corrected to one time point. The correction accuracy was assessed against DTloss estimated by paralyzable model. The accuracy of projection-based DTloss correction for SPECT was evaluated. A method to model projection DTloss based on a subset of measured projection DTloss was investigated. The relation of DTloss between photopeak and scatter EW was explored.Results: The fractional DTloss was uniform across the FOV (r > 0.99), validating condition 1. The MS method was accurate to > 99% for planar and SPECT. Measured DTloss from 3-to-5 projections/detector may be used to estimate DTloss with accuracy > 98% for all SPECT projections by modeling DTloss with measured projection rate. The correction factor in photopeak and scatter EW are equivalent with > 99% agreement.Conclusion: MS method can accurately correct planar and SPECT DTloss. Sparse sampling of the projection DTloss allows acquiring MS counts with high statistics with minimal additional study duration making it clinically practical.--------------------------------------Cite this article as: Siman W, Kappadath SC. SPECT deadtime count loss correction using monitor source method. Int J Cancer Ther Oncol 2014; 2(2):020234. DOI: 10.14319/ijcto.0202.34

Venous thromboembolism (VTE) is a term including deep vein thrombosis (DVT) and pulmonary embolism (PE). Timely and accurate diagnosis of both is essential as delayed or missed diagnoses can result in death or longer term complications. Patients with suspected DVT should initially undergo a pretest probability Wells score. Depending on pretest probability Wells score they should then either proceed to two-point ultrasound scanning or D-dimer testing. Likewise, patients suspected of PE should undergo a two-level PE Wells score, and, if scored likely, a computed tomography pulmonary angiogram (CTPA), or, if there is a low pretest probability score, D-dimer testing. If positive, patients should undergo CTPA. Ventilation perfusion scanning (V/Q scan) or V/Q SPECT should be considered in place of CTPA if there is allergy to contrast media or renal impairment.

TPS10600 Background: Prognosis of patients with osteoblastic metastases from osteosarcoma is extremely poor. Given the heterogeneity in the biology of osteosarcoma, a novel approach is needed to overcome the current therapeutic plateau. Preclinical studies in rodents with alpha particle 223RaCl2 (223Ra) showed avid skeletal deposition, and relative sparing of the bone marrow. Experience with 223Ra in phase I, II and III trials in men with metastatic prostate cancer confirmed excellent activity against bone metastases and a low toxicity profile (i.e., a high therapeutic index) and has been US FDA approved for prostate cancer. Because of the unique physical properties of 223Ra, this agent is anticipated to be a highly effective and better-tolerated treatment for bone-forming sarcoma. We hypothesize that can be safely administered to osteosarcoma patients, and early response and / or resistance signals can be assessed by correlative imaging studies and biomarkers. Methods: We are conducting an investigator i...

Purpose: To optimize 90Y-PET/CT image reconstruction for quantitative accuracy and optimal image quality.Methods: PET/CT scans of a NEMA IEC phantom (3GBq 90YCl2, sphere uptake ratio of ~7) were acquired on 4 GE (BGO:DSTE, DST & LYSO:DRX, D690) and 1 Siemens (LSO:mCT) scanners in 3D list mode with 30 min/bed; replayed to 20, 15, 10 min/bed. Iterative reconstruction parameters explored were SUB × IT (3 – 80) and post-reconstruction filters: transaxial: 5 – 25 mm cutoff & z-axis (GE only): std vs. heavy. The effects of PSF modeling and TOF correction were evaluated for D690 and mCT. VOIs were drawn inside spheres and in adjacent background regions. The accuracy of sphere activity concentration (AC in kBq/mL) and contrast to noise ratio (CNR) was calculated as function of SUB × IT. Reconstructed PET images were also evaluated qualitatively for sphere detectability and artifacts.Results: AC converged to 70 – 90% accuracy for 37 mm sphere and further degraded for smaller spheres. Spheres at max CNR might not reach AC convergence yet. Smaller spheres have slower convergence but reach CNR max together with other spheres. Scan duration did not strongly affect sphere convergence but shorter scans increased noise and reduced detectability; 13 mm spheres were not visible going from 30 to 15 min/bed. Heavy z-axis (GE) and transaxial filter with 10 – 15 mm cutoff helped suppress noise and increase sphere detectability at the expense of accuracy. Images with PSF+TOF corrections had higher sphere detectability and converged faster. Hot cluster artifacts 5 – 7 times the background were seen in some cases with SUB × IT near convergence and lower filtration.Conclusion: Accurate 90Y AC was not achieved even at convergence and noise is a major concern. 90YPET/CT reconstruction parameters are different than those for 18F and benefit substantially from PSF+TOF corrections. Optimum image quality and accurate AC may not be simultaneously achievable.----------------------------------------Cite this article as: Siman W, Mawlawi O, Kappadath SC. 90Y PET/CT quantitative accuracy and image quality. Int J Cancer Ther Oncol 2014; 2(2):020235. DOI: 10.14319/ijcto.0202.35

Purpose: To characterize the personal dose equivalent energy response, Hp(10), for electronic personal dosimeters (EPDs) with commonly used radionuclides in nuclear medicine. Methods: Rados‐60R with an energy compensated PIN diode and the SAIC Pd‐10i with a miniature energy compensated Geiger‐Muller tube EPDs were characterized. The experimental setup and calculation of EPD energy responses were based on ANSI/HPS N13.11‐2009. 15 Rados‐60R and 2 SAIC Pd‐10i units were irradiated using 99mTc, 131I, and 18F radionuclides corresponding to emission energies at 140 keV, 364 keV, and 511 keV, respectively. EPDs output in Hp(10) [mrem] were recorded for free‐in‐air and with 15‐in. thick PMMA to simulate backscatter form the torso. Simultaneous exposure rate measurements were also performed using 2 Victoreen 451‐B ionization survey meters to serve as gold standard measurements. The expected EPD Hp(10) values were calculated from exposure (from the Victoreen 451‐B survey meters) to Hp(10) as specified in ANSI/HPS N13.11‐2009 and ICRU Report 57. These measurements were repeated for both setups at all energies. Results: On average, in the presence of acrylic, the reported Rados‐60R values increased by 27%, 12%, and 13% and those reported by the SAIC Pd‐10i increased by 23%, 19%, and 12% at 140 keV, 364 keV, and 511 keV, respectively. The Rados‐60R EPDs were observed to under‐respond at 140 keV by ∼16%, and agreed to within 5% and 10% of the expected values at 364 and 511 keV, respectively. The SAIC Pd‐10i EPDs were observed to over‐respond at 140 keV by ∼20%, and agreed to within 5% of the expected values 364 and 511 keV. Conclusion: Both Rados‐60R and SAICPD‐10i EPDs displayed Hp(10) values that were accurate to within 10% at energies above 364 keV. However, their accuracies degraded to 15–20% at lower energies (140 keV) suggesting the need to calculate energy dependent correction factors.

Purpose: Digital tomosynthesis is a new spin on an old idea. It has been extensively studied and developed, but is just beginning to find its way into the clinic. We seek to compare digital tomosynthesis to conventional tomography utilizing a computed radiography(CR) system. To this end, we have developed quantitative measures to compare image quality and dose between images acquired using digital tomosynthesis and those acquired using conventional tomography with CR.Materials and methods: “Standard” IVP studies were performed on uniform acrylic phantoms. Dose in terms of entrance air kerma (EAK) was measured for each of the studies. The uniform phantom images were also used to quantify non‐uniformities in the images both globally and locally. Also, images were evaluated for the presence of artifacts. Results: EAK values for a standard IVP study (3 scout images, 3 tomographic cuts during 3 phases) of a “medium” patient consisting of 6 inches of acrylic ranged from 3.54 mGy to 80.1 mGy, depending upon technique, for digital tomosynthesis studies to 51.2 mGy for the same CR study. Also, keep in mind that additional planes or slice thicknesses can be derived from the digital data at no extra dose cost to the patient. Uniformity measures varied significantly in processed images for digital tomosynthesis studies acquired at varying techniques. Uniformity was consistent throughout conventional tomographic studies. Processed digital tomosynthesisimages also displayed artifacts, some which mimic pathologic anatomy.Conclusions: Digital tomosynthesis has the potential to significantly reduce patient doses in IVP studies. However, techniques must be chosen appropriately to maximize image quality and minimize the presence of artifacts.