Multi-modal imaging of high-risk ductal carcinoma in situ of the breast using C2Am: a targeted cell death imaging agent

Abstract: Background: Ductal carcinoma in situ (DCIS) is a non-invasive form of early breast cancer, with a poorly understood natural history of invasive transformation. Necrosis is a well-recognized adverse prognostic feature of DCIS, and non-invasive detection of its presence and spatial extent could provide information not obtainable by biopsy. We describe here imaging of the distribution and extent of comedo-type necrosis in a model of human DCIS using C2Am, an imaging agent that binds to the phosphatidylserine exposed by necrotic cells. Methods: We used an established xenograft model of human DCIS that mimics the histopathological features of the disease. Planar near-infrared and optoacoustic imaging, using fluorescently labeled C2Am, were used to image non-invasively the presence and extent of lesion necrosis. Results: C2Am showed specific and sensitive binding to necrotic areas in DCIS tissue, detectable both in vivo and ex vivo. The imaging signal generated in vivo using near-infrared (NIR) fluorescence imaging was up to 6-fold higher in DCIS lesions than in surrounding fat pad or skin tissue. There was a correlation between the C2Am NIR fluorescence (Pearson R = 0.783, P = 0.0125) and optoacoustic signals (R > 0.875, P < 0.022) in the DCIS lesions in vivo and the corresponding levels of cell death detected histologically. Conclusions: C2Am is a targeted multi-modal imaging agent that could complement current anatomical imaging methods for detecting DCIS. Imaging the presence and spatial extent of necrosis may give better prognostic information than that obtained by biopsy alone

Supplementary comparison of the measurement of the alpha and beta particle surface emission rates from large area sources (CCRI(II)-S10 LASCE)

International audienceIn 2009, the Consultative Committee for Ionizing Radiation (CCRI) approved its first supplementary comparison, to be organized by the ENEA (as the pilot laboratory), for the measurement of the alpha and beta particle surface (i.e. 2 solid angle) emission rate from large area sources of the type used for calibrating surface contamination monitors. Five sources were disseminated to the twenty-three participating laboratories consisting of one each of 241Am, 14C, 147Pm and 90Sr for emission rate measurements, with one additional 90Sr source for the evaluation of source uniformity. Measurements of the radionuclide activity and radionuclidic purity were also made although not strictly required. This report describes the organization of this comparison and the material and measurement methods used. The proposed supplementary comparison reference values (SCRV) for each of the comparison measurands are given, together with the Degrees of Equivalence and their associated uncertainties for each participating laboratory. The results of this supplementary comparison may be used as evidence by participating National Metrology Institutes (NMIs) and Designated Institutes (DIs) when submitting calibration and measurement capabilities (CMCs) for the given radionuclides for similar types of large area sources; this is an important aspect of this comparison, given that only one other international supplementary comparison for surface emission rates had been organized before

Cardiovascular CT angiography in neonates and children:Image quality and potential for radiation dose reduction with iterative image reconstruction techniques

<p>To evaluate image quality (IQ) of low-radiation-dose paediatric cardiovascular CT angiography (CTA), comparing iterative reconstruction in image space (IRIS) and sinogram-affirmed iterative reconstruction (SAFIRE) with filtered back-projection (FBP) and estimate the potential for further dose reductions.</p><p>Forty neonates and children underwent low radiation CTA with or without ECG synchronisation. Data were reconstructed with FBP, IRIS and SAFIRE. For ECG-synchronised studies, half-dose image acquisitions were simulated. Signal noise was measured and IQ graded. Effective dose (ED) was estimated.</p><p>Mean absolute and relative image noise with IRIS and full-dose SAFIRE was lower than with FBP (P <0.001), while SNR and CNR were higher (P <0.001). Image noise was also lower and SNR and CNR higher in half-dose SAFIRE studies compared with full-and half-dose FBP studies (P <0.001). IQ scores were higher for IRIS, full-dose SAFIRE and half-dose SAFIRE than for full-dose FBP and higher for half-dose SAFIRE than for half-dose FBP (P <0.05). Median weight-specific ED was 0.3 mSv without and 1.36 mSv with ECG synchronisation. The estimated ED of half-dose SAFIRE studies was 0.68 mSv.</p><p>IR improves image noise, SNR, CNR and subjective IQ compared with FBP in low-radiation-dose paediatric CTA and allows further dose reductions without compromising diagnostic IQ.</p><p>aEuro cent Iterative reconstruction techniques significantly improve non-invasive cardiovascular CT in children.</p><p>aEuro cent Using half traditional radiation dose image quality is higher with iterative reconstruction.</p><p>aEuro cent Iterative reconstruction techniques may allow further radiation reductions in paediatric cardiovascular CT.</p>