Intérêt de l’imagerie hybride TEMP-TDM pour la détection du ganglion sentinelle dans les cancers du sein

IntroductionSingle-Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) is an hybrid technique which associates functional and morphological images. The aim of this study was to assess the role of SPECT-CT lymphoscintigraphy in sentinel node identification in patients with breast cancer.MethodsTwelve months prospective study was undertaken. Lymphoscintigraphy comprising planar and SPECT-CT acquisition was performed in 51 consecutive patients with breast cancer (mean age: 62 ± 11.3, range: 33–83 years). Planar and SPECT-CT images were interpreted separately and the two imaging techniques were compared with respect to their ability to identify sentinel node.ResultsAn add-value of SPECT-CT images was evidenced in 31% of cases: a more accurate anatomic localization in 21% of cases and identification of undeterminate sites of uptake in 10% of cases. Furthermore, SPECT-CT detected intramammary (4% of cases) and retromammary (2% of cases) sentinel nodes missed by planar imaging. SPECT-CT was more sensitive for internal mammary drainage detection (6% of cases). The added value proved higher in obese patients. Finally, functional and anatomical images fusion and three-dimensional overview provided clear and readily usable informations to the surgeon.ConclusionHybrid SPECT-CT imaging improves the preoperative localisation of sentinel nodes in patients with breast cancer, in particular in obese patients. SPECT-CT provides readily usable informations to the surgeon.     

Radioprotection après injection thérapeutique de [131I]-mIBG : données préalables à l’ouverture du protocole MIITOP-0607

IntroductionThe MIITOP-0607 protocol, studying the efficiency of administration of topotecan and myelosupressive [¹³¹I]-mIBG therapy in children affected by neuroblastoma, needed to assess irradiation risks on staff and family of children to obtain the agreement of the Autorité de sûreté nucléaire (ASN). Our aim was to quantify irradiation of the staff during preparation of the mIBG and to assay the irradiation and contamination of the accompanying persons.Patient and methodsRadiation exposure of the staff was measured during the preparation, transport and administration of the first treatment. Salivary and urinary excretions were monitored well as the atmospheric radioactivity. Radiation exposure and contamination of the accompanying persons were also measured.ResultsFinger dose of 3 mSv and whole body dose of 50 μSv were estimated for preparation of an 11.1 GBq syringe. Irradiation from urinary activity can be as low as 100 μSv if a dedicated device is used. Salivary excretion decreased rapidly during the first 24 hours. Atmospheric contamination always remained below 25 Bq m^?3. Total irradiation of the accompanying persons is about 2.35 mSv for the two consecutive injections (9,3 and 11,1 GBq). Internal contamination occurred only once and corresponded to a 27 μSv whole body irradiation and 670 μSv thyroid irradiation.ConclusionThis study shows the safety of [¹³¹I]-mIBG treatments using high activities. The involved dose is not negligible but seems to be acceptable in the specific paediatric oncology context if radioprotection instructions are met and if optimization of protocols is performed.     

Prediction of time-integrated activity coefficients in PRRT using simulated dynamic PET and a pharmacokinetic model

PurposeTo investigate the accuracy of predicted time-integrated activity coefficients (TIACs) in peptide-receptor radionuclide therapy (PRRT) using simulated dynamic PET data and a physiologically based pharmacokinetic (PBPK) model.MethodsPBPK parameters were estimated using biokinetic data of 15 patients after injection of (152 ± 15) MBq of ¹¹¹In-DTPAOC (total peptide amount (5.78 ± 0.25) nmol). True mathematical phantoms of patients (MPPs) were the PBPK model with the estimated parameters. Dynamic PET measurements were simulated as being done after bolus injection of 150 MBq ⁶⁸Ga-DOTATATE using the true MPPs. Dynamic PET scans around 35 min p.i. (P₁), 4 h p.i. (P₂) and the combination of P₁ and P₂ (P₃) were simulated. Each measurement was simulated with four frames of 5 min each and 2 bed positions. PBPK parameters were fitted to the PET data to derive the PET-predicted MPPs. Therapy was simulated assuming an infusion of 5.1 GBq of ⁹⁰Y-DOTATATE over 30 min in both true and PET-predicted MPPs. TIACs of simulated therapy were calculated, true MPPs (true TIACs) and predicted MPPs (predicted TIACs) followed by the calculation of variabilities v.ResultsFor P₁ and P₂ the population variabilities of kidneys, liver and spleen were acceptable (v < 10%). For the tumours and the remainders, the values were large (up to 25%). For P₃, population variabilities for all organs including the remainder further improved, except that of the tumour (v > 10%).ConclusionTreatment planning of PRRT based on dynamic PET data seems possible for the kidneys, liver and spleen using a PBPK model and patient specific information.     

The effect of tumour geometry on the quantification accuracy of planar 123I phantom images

IntroductionAccurate activity quantification is applied in radiation dosimetry. Planar images are important for quantification of whole-body images, enabling assessment of biodistribution from radionuclide administrations. We evaluated the effect of tumour geometry on quantification accuracy of ¹²³I planar phantom studies, including various tumour sizes, tumour-liver distances and two tumour-background ratios.Methods and materialsAn in-house manufactured abdominal phantom was equipped with a liver, different size cylindrical tumours, and a rod for tumour-liver distance variation. The geometric mean method with scatter and attenuation corrections was used for image processing. Scatter and attenuation corrections were made using the triple energy window scatter correction technique and a printed transmission sheet source, respectively. Region definitions for tumour activity distribution compensated for the partial volume effect (PVE). Activity measured in the dose calibrator served as reference for determining quantification accuracy.ResultsThe smallest tumour had the largest percentage deviation with an average activity underestimation of 34.6 ± 1.2%. Activity values for the largest tumour were overestimated by 3.1 ± 3.0%. PVE compensation improved quantification accuracy for all tumour sizes yielding accuracies of <12.4%. Scatter contribution to the tumours from the liver had minimal effect on quantification accuracy at tumour-liver distances >3 cm. With PVE compensation, increased tumour-background ratio resulted in a percentage increase of up to 26.3%.ConclusionWhen applying relevant corrections for scatter, attenuation and PVE without background activity, quantification accuracy of <13% was obtained. We demonstrated the successful implementation of a practical technique to obtain quantitative information from ¹²³I planar images.     

Synthesis,radiosynthesis and first in vitro evaluation of novel PET-tracers for the dopamine transporter: [11C]IPCIT and [18F]FE@IPCIT

IntroductionPresent data indicate that merging beneficial structural elements from previously published DAT-ligands highest DAT affinity, selectivity and a suitable metabolic profile should be achieved. This combination led to the development of IPCIT and FE@IPCIT.MethodsPrecursor synthesis was done starting from cocaine in a six step reaction. O-[¹¹C]-methylation was established using [¹¹C]methyl iodide, optimized and subsequently automated. Small scale ¹⁸F-fluroroethylation as well as optimization of reaction parameters and automation were performed. Affinity and selectivity of the candidate substances were tested in standard binding experiments on human membranes. Metabolic stability and blood–brain-barrier (BBB) penetration were determined.ResultsPrecursor compound, IPCITacid, and reference compounds, IPCIT and FE@IPCIT, were obtained in 4.9%, 12.7% and 4.1% yield, respectively. Automated radiosynthesis of [¹¹C]IPCIT yielded 1.9 ± 0.7 GBq (12.5 ± 4%, corrected for decay). Optimum parameters for ¹⁸F-fluoroethylation were 110 °C for 15 min under TBAH catalysis, yielding 67 ± 16% radiochemical incorporation. Affinity was determined as 1.7 ± 0.6 nM for IPCIT, 1.3 ± 0.2 nM for FE@IPCIT and 37 ± 13 nM for the precursor molecule, IPCIT-acid. Results from in vitro and in silico evaluations revealed high stability but also high lipophilicity.ConclusionPresent data indicate high affinity and stability of both IPCIT and FE@IPCIT. Radiolabelling, optimization of reaction parameters and automation succeeded. On the other hand, data concerning BBB-penetration are not promising.     

Comparaison entre OSEM-3D et rétroprojection filtrée pour les images traitées par SISCOM dans l’épilepsie temporale

IntroductionWhen ictal and interictal brain SPECT are reconstructed with filtered backprojection (FBP), the noise level of subtraction images is frequently high and requires the use of thresholding methods. The aim of this study was to compare the subtraction images for cerebral SPECT reconstructed either with FBP or with a 3D iterative reconstruction method (OSEM-3D).Material and methodsAfter optimisation of the reconstruction parameters on phantom, the subtraction SPECT images, which were obtained with FBP or with OSEM-3D and coregistered with MRI images, were analyzed in 15 patients with refractory temporal epilepsy.ResultsOn phantom and with the constrain of high enough spatial resolution (full width at half of maximum for a punctual source less than or equal to 11 mm) were reached using: (i) a Butterworth filter with a cut-off frequency of 0.4 Nyquist at order 6 for FBP and (ii) five iterations, 16 subsets and a 9 mm gaussian filter for OSEM-3D. On the subtraction images, which were obtained with these optimal parameters, the temporal foci from patients were smaller with OSEM-3D than with FBP (11 ± 6 cm³ versus 17 ± 10 cm³, P = 0.02), mean voxel activities were equivalent between the two methods within temporal foci (6.30 ± 3.13 counts versus 6.34 ± 4.93 counts) but these activities were dramatically reduced by OSEM-3D within background regions (0.02 ± 0.02 counts versus 0.19 ± 0.12 counts, P < 0.001).ConclusionFor the ictal–interictal subtraction SPECT images, which are obtained in patients with refractory temporal epilepsy, the use of an optimized OSEM-3D method leads to dramatically reduce the volume of temporal foci, as well as the background noise level, two properties that are likely to facilitate the detection and localisation of epilepsy foci.     

La perfusion pulmonaire en morphoTEMP dans le diagnostic de l’embolie pulmonaire : comparaison à la scintigraphie pulmonaire planaire de ventilation/perfusion

The aim of this study is to assess a new tool for the diagnosis of acute pulmonary embolism (PE): single-photon emission computed tomography lung perfusion imaging associated with unenhanced computed tomography (SPECT/CT) compared to planar ventilation-perfusion (VQ) lung scintigraphy.MethodsOne hundred and three patients with suspected acute PE underwent VQ scintigraphy (two scans were uninterpretable) followed by perfusion SPECT/CT. The two types of images were analysed separately: (1) according to the modified PIOPED scintigraphic criteria for VQ lung scan and (2) with regard to SPECT/CT mismatches suggestive acute PE (segmental perfusion defects detected on SPECT images not matched with CT abnormalities).ResultsOn average, the number of segmental perfusion defects per patient was higher with SPECT/CT than with planar scintigraphy (4.3 ± 3.6 versus 2.8 ± 2.6; p < 0.001). A mismatch was found with SPECT-CT in 0% (0/18) of normal scintigraphy, and 8% (3/39) for low, 32% (8/25) for intermediate and 74% (14/19) for high probabilities of PE at scintigraphy. The presence of a SPECT/CT mismatch was also associated with higher pretest probability of acute PE (p = 0.001), even for the 25 patients in the intermediate-probability subgroup (p = 0.02). Finally, a SPECT/CT match was found in 29 patients that was not suggestive of acute PE due to the presence, in areas with perfusion defects on SPECT images, of the following CT abnormalities: hypodensity and/or emphysema (71%), condensation or atelectasis (38%), pleural disease (7%), extrapulmonary structure (14%) and/or bronchial obstruction (7%).ConclusionIn patients with suspected acute PE, the results obtained with pulmonary SPECT/CT images are consistent with those obtained with VQ scintigraphy and the pretest probability of PE. Further studies comparing SPECT/CT imaging with angiographic techniques are now required to evaluate more specifically the diagnostic value of this new tool.     

Dosimétrie rénale du 177Lu-Dotatate : mise en place au sein du Groupement hospitalier Est des Hospices Civils de Lyon

IntroductionThe kidney is considered as a critical dose-limiting organ with ¹⁷⁷Lu-Dotatate. Renal dosimetry could play a role in optimizing treatment. We present a feedback on the implementation of renal dosimetry in our medical center.Material and methodThe renal dosimetry of the 1st administration of ¹⁷⁷Lu-Dotatate (approximately 7.4 GBq) has been performed for seven patients. The reference dosimetry strategy included 4 post-therapeutic SPECT/CT at 6 h, 24 h, 72 h and 168 h and anatomical renal volume delineation (VOI). Alternative dosimetric strategies consisted of 72 h or 168 h time point eviction (time sampling A or B) and delimitation of 1 or 3 spherical VOIs (3 mL each) per kidney (“1 sVOI” or “3 sVOI” methods). The quantitative scintigraphic processing was performed by 4 operators using Dosimetry Toolkit®. The renal dose was calculated with OLINDA/EXM® 2.0.ResultsThe calculated mean absorbed renal dose was 3.68 ± 0.68 Gy with the reference method, with no significant impact of interoperator variability (P = 0.41). It was in satisfactory agreement with time sampling A or B. The “1 sVOI” and “3 sVOI” methods overestimated the renal dose (5.01 ± 0.94 Gy and 4.91 ± 0.79 Gy respectively), with a significant impact on interoperator variability (P < 0.05), despite a reduction in processing time.ConclusionThe main logistic constraint of ¹⁷⁷Lu-Dotatate renal dosimetry in our center is the time-consumption due to SPECT/CT acquisitions. A possible approach supported by our preliminary results is a reduction in the number of scintigraphic acquisitions.     

Optimisation of reconstruction,volumetry and dosimetry for 99mTc-SPECT and 90Y-PET images: Towards reliable dose-volume histograms for selective internal radiation therapy with 90Y-microspheres

PurposeIn Selective Internal Radiation Therapy (SIRT), ^99mTc-MAA SPECT images are commonly used to predict microspheres distribution but recent works used ⁹⁰Y-microspheres PET images. Nevertheless, evaluation of the predictive power of ^99mTc-MAA has been hampered by the lack of reliable comparisons between ^99mTc-SPECT and ⁹⁰Y-PET images. Our aim was to determine the “in situ” optimisation procedure in order to reliably compare ^99mTc-SPECT and ⁹⁰Y-PET images and achieve optimal personal dosimetry.MethodsWe acquired ^99mTc-SPECT/CT and ⁹⁰Y-PET/CT images of NEMA and Jaszczak phantoms. We found the best reconstruction parameters for quantification and for volume estimations. We determined adaptive threshold curves on the volumetric reconstruction. We copied the optimised volumes on the quantitative reconstruction, named here the “cross volumes” technique. Finally, we compared ^99mTc-SPECT and ⁹⁰Y-PET Dose Volume Histograms.ResultsOur “in situ” optimisation procedure decreased errors on volumes and quantification (from −44.2% and −15.8% to −3.4% and −3.28%, respectively, for the 26.5 mL PET phantom sphere). Moreover, ^99mTc-SPECT and ⁹⁰Y-PET DVHs were equivalent only after the optimisation procedure (difference in mean dose <5% for the three biggest spheres).ConclusionsThis work showed that a preliminary “in situ” phantom study was necessary to optimise volumes and quantification of ^99mTc-SPECT and ⁹⁰Y-PET images and allowed to achieve a reliable comparison between patient treatment planning and post implant dosimetry, notably by the use of the “cross volumes” technique. Methodology developed in this work will enable robust evaluations of the predictive power of ^99mTc-SPECT, as well as dose-response relationship and side effects in SIRT treatments.     

A let-7 microRNA polymorphism in the KRAS 3′-UTR is prognostic in oropharyngeal cancer

IntroductionThis study aimed to investigate the effect of genetic polymorphisms in miRNA sequences, miRNA target genes and miRNA processing genes as additional biomarkers to HPV for prognosis in oropharyngeal squamous cell carcinoma (OPSCC) patients. Secondarily, the prevalence of HPV-associated OPSCC in a European cohort was mapped.MethodsOPSCC patients (n = 122) were genotyped for ten genetic polymorphisms in pre-miRNAs (pre-mir-146a, pre-mir-196a2), in miRNA biosynthesis genes (Drosha, XPO5) and in miRNA target genes (KRAS, SMC1B). HPV status was assessed by p16 immunohistochemistry (IHC) and high-risk HPV in situ hybridization (ISH) or by p16 IHC and PCR followed by enzyme-immunoassay (EIA). Overall and disease specific survival were analysed using Kaplan–Meier plots (log-rank test). Cox proportional hazard model was used to calculate hazard ratios (HR).ResultsThe overall HPV prevalence rate in our Belgian/Dutch cohort was 27.9%. Patients with HPV⁺ tumours had a better 5-years overall survival (78% vs. 46%, p = 0.001) and a better 5-years disease specific survival (90% vs. 70%, p = 0.016) compared to patients with HPV⁻ tumours. In multivariate Cox analysis including clinical, treatment and genetic parameters, HPV negativity (HR = 3.89, p = 0.005), advanced T-stage (HR = 1.81, p = 0.050), advanced N-stage (HR = 5.86, p = 0.001) and >10 pack-years of smoking (HR = 3.45, p = 0.012) were significantly associated with reduced overall survival. The variant G-allele of the KRAS-LCS6 polymorphism was significantly associated with a better overall survival (HR = 0.40, p = 0.031).ConclusionsOur results demonstrate that OPSCC patients with the KRAS-LCS6 variant have a better outcome and suggest that this variant may be used as a prognostic biomarker for OPSCC.     

Exenatide-loaded PLGA microspheres with improved glycemic control: In vitro bioactivity and in vivo pharmacokinetic profiles after subcutaneous administration to SD rats

A subcutaneous exenatide delivery system was developed and characterized in vitro and in vivo. The results clearly showed that the exenatide loaded PLGA microspheres prepared by using a non-aqueous processing medium had low burst release and high drug encapsulation efficiency. Exenatide loaded in the microspheres preserved its bioactivity. The pharmacokinetics parameters were determined after subcutaneous administration of microspheres to SD rats. The plasma concentration of the single dose of the sustained-release microspheres attained C_max of 108.19 ± 14.92 ng/ml at t_max of 1.33 ± 0.58 h and the t_1/2 was 120.65 ± 44.18 h. There was a linear correlation between the in vitro and in vivo release behavior (R² = 0.888). Exenatide loaded microspheres may prove to have great potential for clinical use.     

Efficient microwave-assisted direct radiosynthesis of [18F]PR04.MZ and [18F]LBT999: Selective dopamine transporter ligands for quantitative molecular imaging by means of PET

PR04.MZ 8-(4-fluoro-but-2-ynyl)-3-p-tolyl-8-aza-bicyclo[3.2.1]octane-2-carboxylic acid methyl ester (1) and LBT999 8-((E)-4-fluoro-but-2-enyl)-3b-p-tolyl-8-aza-bicyclo[3.2.1]octane-2β-carboxylic acid methyl ester (2) are selective dopamine reuptake inhibitors, derived from cocaine. Compounds 1 and 2 were labelled with fluorine-18 at their terminally fluorinated N-substituents employing microwave enhanced direct nucleophilic fluorination. K[¹⁸F]F^? Kryptofix^®222 cryptate, tetrabutyl ammonium [¹⁸F]fluoride and caesium [¹⁸F]fluoride were compared as fluoride sources under conventional and microwave enhanced conditions. Fluorination yields were remarkably increased under microwave irradiation for all three fluoride salts. Radiochemically pure (>98%) [¹⁸F]PR04.MZ (0.95–1.09 GBq, 42–135 GBq/μmol) was obtained within 34–40 min starting from 3.0 GBq [¹⁸F]fluoride ion in 32–36% non-decay-corrected overall yield using K[¹⁸F]F^?Kryptofix^®222 cryptate in MeCN.     

Congo Red attached monosize poly(HEMA-co-MMA) microspheres for use in reversible enzyme immobilisation

Monosize and non-porous poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) (poly(HEMA-co-MMA)), microspheres were prepared by dispersion polymerisation of HEMA and MMA in an ethanol–water medium in the presence of an initiator (α,α′-azobisisobutyronitrile, AIBN). An affinity dye, i.e. Congo Red (CR) was attached covalently and then Fe³⁺ ions were incorporated. The poly(HEMA-co-MMA)-CR attached and poly(HEMA-co-MMA)-CR-Fe³⁺ incorporated microspheres were used in the immobilisation of glucose oxidase (GOD) via adsorption. The adsorption capacities of these microspheres were determined by varying the concentration of GOD in the adsorption medium. GOD adsorption capacities of the Fe³⁺ incorporated microspheres (165 mg g⁻¹) was greater than that of the dye-attached microspheres (126 mg g⁻¹). The non-specific adsorption of the GOD on the poly(HEMA-co-MMA) microspheres was negligible. The K_m values for both immobilised poly(HEMA-co-MMA)-CR-GOD (7.2) and poly(HEMA-co-MMA)-CR-Fe³⁺-GOD (6.8) were higher than that of the free enzyme (6.6 mM). Optimum reaction pH was 5.0 for free and 7.0 for both immobilised preparations. Optimum reaction temperature of the adsorbed enzymes was 10 °C higher than that of the free enzyme and was significantly broader. After 10 successive uses the retained activity of the adsorbed enzyme was 93%. It was observed that enzyme could be repeatedly adsorbed and desorbed on the CR attached poly(HEMA-co-MMA) microspheres without significant loss in adsorption capacity or enzyme activity.     

Imaging performance of phase-contrast breast computed tomography with synchrotron radiation and a CdTe photon-counting detector

PurposeWithin the SYRMA-CT collaboration based at the ELETTRA synchrotron radiation (SR) facility the authors investigated the imaging performance of the phase-contrast computed tomography (CT) system dedicated to monochromatic in vivo 3D imaging of the female breast, for breast cancer diagnosis.MethodsTest objects were imaged at 38 keV using monochromatic SR and a high-resolution CdTe photon-counting detector. Signal and noise performance were evaluated using modulation transfer function (MTF) and noise power spectrum. The analysis was performed on the images obtained with the application of a phase retrieval algorithm as well as on those obtained without phase retrieval. The contrast to noise ratio (CNR) and the capability of detecting test microcalcification clusters and soft masses were investigated.ResultsFor a voxel size of (60 μm)³, images without phase retrieval showed higher spatial resolution (6.7 mm⁻¹ at 10% MTF) than corresponding images with phase retrieval (2.5 mm⁻¹). Phase retrieval produced a reduction of the noise level and an increase of the CNR by more than one order of magnitude, compared to raw phase-contrast images. Microcalcifications with a diameter down to 130 μm could be detected in both types of images.ConclusionsThe investigation on test objects indicates that breast CT with a monochromatic SR source is technically feasible in terms of spatial resolution, image noise and contrast, for in vivo 3D imaging with a dose comparable to that of two-view mammography. Images obtained with the phase retrieval algorithm showed the best performance in the trade-off between spatial resolution and image noise.     

The Italian multicentre dosimetric study for lesion dosimetry in 223Ra therapy of bone metastases: Calibration protocol of gamma cameras and patient eligibility criteria

PurposeThe aims of this work were to explore patient eligibility criteria for dosimetric studies in ²²³Ra therapy and evaluate the effects of differences in gamma camera calibration procedures into activity quantification.MethodsCalibrations with ²²³Ra were performed with four gamma cameras (3/8-inch crystal) acquiring planar static images with double-peak (82 and 154 keV, 20% wide) and MEGP collimator. The sensitivity was measured in air by varying activity, source-detector distance, and source diameter. Transmission curves were measured for attenuation/scatter correction with the pseudo-extrapolation number method, varying the experimental setup. ²²³Ra images of twenty-five patients (69 lesions) were acquired to study the lesions visibility. Univariate ROC analysis was performed considering visible/non visible lesions on ²²³Ra images as true positive/true negative group, and using as score value the lesion/soft tissue contrast ratio (CR) derived from ^99mTc-MDP WB scan.ResultsSensitivity was nearly constant varying activity and distance (maximum s.d. = 2%). Partial volume effects were negligible for object area ⩾960 mm². Transmission curve measurements are affected by experimental setup and source size, leading to activity quantification errors up to 20%. The ROC analysis yielded an AUC of 0.972 and an optimal threshold of CR of 10, corresponding to an accuracy of 92%.ConclusionThe minimum calibration protocol requires sensitivity and transmission curve measurements varying the object size, performing a careful procedure standardisation. Lesions with ^99mTc-MDP CR higher than 10, not overlapping the GI tract, are generally visible on ²²³Ra images acquired at 24 h after the administration, and possibly eligible for dosimetric studies.     

Comparison of quadrant-specific breast cancer incidence trends in the United States and England between 1975 and 2013

BackgroundUK breast cancer incidence rates suggest that upper outer quadrant (UOQ) cancers have risen disproportionately compared with other areas over time. We aimed to provide a comparison of the trend in quadrant-specific breast cancer incidence between the United States (US) and England, and determine whether a disproportionate UOQ increase is present.MethodsSurveillance Epidemiology and End Results (SEER) cancer registry data were obtained on 630,007 female breast cancers from 1975 to 2013. English cancer registry data were obtained on 1,121,134 female breast cancers from 1979 to 2013. Temporal incidence changes were analysed using negative binomial regression. Interaction terms determined whether incidence changes were similar between sites.ResultsEnglish breast cancer incidence in the UOQ rose significantly from 13% to 28% from 1979 to 2013 whereas no significant increase was observed among SEER data. The significant interaction between quadrant and year of diagnosis (p < 0.001) in both SEER and English data indicates that breast cancer incidence in each quadrant changed at a different rate. Incidence in the UOQ rose disproportionately compared to the nipple (SEER IRR = 0.81, p < 0.001; England IRR = 0.78, p < 0.001) and axillary tail (SEER IRR = 0.87, p = 0.018; England IRR = 0.69, p < 0.001) in both SEER and England. In addition, incidence rose disproportionately in the UOQ compared to non-site-specific tumours in England (Overlapping lesions IRR = 0.81, p = 0.002; NOS IRR = 0.78, p < 0.001). The proportion of non-site-specific tumours was substantially higher in England than SEER throughout the study period (62% in England; 39% in SEER).ConclusionsBreast cancer incidence in the UOQ increased disproportionately compared to non-site-specific tumours in England but not in SEER, likely due to the decrease in non-site-specific tumours observed in England over time. There may be real differences in incidence between the two countries, possibly due to differences in aetiology, but is much more likely to be an artefact of changing data collection methods and improvements in site coding in either country.     

Faisabilité et intérêt d’un nouvel algorithme de reconstruction des images TEP-18FDG (AW OSEM DR) pour la délimitation des volumes cibles en radiothérapie. À propos d’un cas de néoplasie ORL

ObjectiveWe compared two reconstruction methods for 18fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) images with “attenuation weighted ordered subset expectation maximization” using either the manufacturer-provided (AW-OSEM) or a “Detector response” (AW-OSEM DR) tomographic operator. We looked at the feasibility of using the latter reconstruction for radiotherapy target volumes definition in cancers of the superior aero-digestive tract (VADS). In this preliminary study, we first assessed the spatial resolution of images obtained with AW-OSEM and AW-OSEM DR on a Biograph™ 6, and secondly target volumes of radiotherapy “Gross Tumor Volume” (GTV), “Clinical Target Volume” (CTV) and “Planning Target Volume” (PTV) obtained with each of these reconstruction methods.Material and methodsThe spatial resolution was measured on a test object containing 4 radioactive point sources. Furthermore, radiotherapy target volumes have been defined with the software Eclipse™ on injected scanner (CT IV) and PET/CT (PET AW-OSEM and PET AW-OSEM DR) images.ResultsSpatial resolution was improved with AW-OSEM DR algorithm reconstruction compared to images obtained with AW-OSEM reconstruction (from 7.5 mm down to 5.4 mm for the highest reduction). GTV from AW-OSEM DR reconstruction with 42 and 50% of the “Standard uptake value maximum” (SUVmax) semi-automatic threshold (1.2 and 0.7 cm³ respectively) were lower than those obtained with AW-OSEM (3.6 and 2.2 cm³ respectively). They were also lower than GTV defined with CT IV (5.5 cm³). It was the same for CTV and PTV.ConclusionThis study showed that AW-OSEM DR reconstruction method allows less impaired spatial resolution than AW-OSEM. In the case of radiotherapy target volumes delineation, AW-OSEM DR may decrease the GTV, CTV and PTV and therefore the risk of side effects associated with organs at risk.     

Comparison between new-generation SiPM-based and conventional PMT-based TOF-PET/CT

PurposeThis study aimed to determine whether the SiPM-PET/CT, Discovery MI (DMI) performs better than the PMT-PET/CT system, Discovery 710 (D710).MethodsThe physical performance of both systems was evaluated using NEMA NU 2 standards. Contrast (%), uniformity and image noise (%) are criteria proposed by the Japanese Society of Nuclear Medicine (JSNM) for phantom tests and were determined in images acquired from Hoffman and uniform phantoms using the DMI and D710. Brain and whole-body [¹⁸F]FDG images were also acquired from a healthy male using the DMI and D710.ResultsThe spatial resolution at 1.0 cm off-center in the DMI and D710 was 3.91 and 4.52 mm, respectively. The sensitivity of the DMI and D710 was 12.62 and 7.50 cps/kBq, respectively. The observed peak noise-equivalent count rates were 185.6 kcps at 22.5 kBq/mL and 137.0 kcps at 29.0 kBq/mL, and the scatter fractions were 42.1% and 37.9% in the DMI and D710, respectively. The D710 had better contrast recovery and lower background variability. Contrast, uniformity and image noise in the DMI were 61.0%, 0.0225, and 7.85%, respectively. These outcomes were better than those derived from the D710 and satisfied the JSNM criteria. Brain images acquired by the DMI had better grey-to-white matter contrast and lower image noise at the edge of axial field of view.ConclusionsThe DMI offers better sensitivity, performance under conditions of high count rates and image quality than the conventional PMT-PET/CT system, D710.     

Development of a transparent,non-cytotoxic,silver ion-exchanged glass with antimicrobial activity and low ion elution

We investigated the antimicrobial, cytotoxicity, skin irritation, and ion elution behaviors of glass doped with silver ions with respect to its application to electronic equipment such as phones and tablet screens. The microbes tested were Escherichia coli, Staphylococcus aureus, and Penicillium funiculosum. AgNO₃ powder was spread on both sides of aluminosilicate glass, and it was heated to 250–280 °C for 10 min. Under optimized heating conditions (260 °C, 10 min), the antimicrobial activity of ion-exchanged glass against bacteria and fungi was over 99.9% after 24 weeks. The glass failed to irritate the skin of experimental animals and was considered non-cytotoxic. The maximum amount of Ag ions that were eluted from the ion-exchanged glass into drinking water was measured at 0.037 ± 0.003 μg L⁻¹, an amount which is several orders of magnitude below the standard limit of 0.1 mg L⁻¹ in drinking water. Ag ion-exchanged glass had characteristics suitable for use as a display screen, such as a light transmittance of 90% and a surface roughness of 0.704 nm. Our findings suggest that glass doped with silver ions is more hygienic than non-doped glass is, and should be applied to display screens and glassware.