An Analysis of Positron Emission Tomography Maximum Standard Uptake Value Among Patients With Head and Neck Cancer Receiving Photon and Proton Radiation.

PURPOSE: One main advantage of proton therapy versus photon therapy is its precise radiation delivery to targets without exit dose, resulting in lower dose to surrounding healthy tissues. This is critical, given the proximity of head and neck tumors to normal structures. However, proton planning requires careful consideration of factors, including air-tissue interface, anatomic uncertainties, surgical artifacts, weight fluctuations, rapid tumor response, and daily variations in setup and anatomy, as these heterogeneities can lead to inaccuracies in targeting and creating unwarranted hotspots to a greater extent than photon radiation. In addition, the elevated relative biological effectiveness at the Bragg peak's distal end can also increase hot spots within and outside the target area. METHODS AND MATERIALS: The purpose of this study was to evaluate for a difference in positron emission tomography (PET) standard uptake value (SUV) after definitive treatment, between intensity modulated proton therapy (IMPT) and intensity modulated photon therapy (IMRT). In addition, we compared the biologic dose between PET areas of high and low uptake within the clinical target volume-primary of patients treated with IMPT. This work is assuming that the greater SUV may potentially result in greater toxicities. For the purposes of this short communication, we are strictly focusing on the SUV and do not have correlation with toxicity outcomes. To accomplish this, we compared the 3- and 6-month posttreatment fluorodeoxyglucose PET scans for 100 matched patients with oropharyngeal cancer treated definitively without surgery using either IMPT (n = 50) or IMRT (n = 50). RESULTS: Our study found a significant difference in biologic dose between the high- and low-uptake regions on 3-month posttreatment scans of IMPT. However, this difference did not translate to a significant difference in PET uptake in the clinical target volume-primary at 3 and 6 months' follow-up between patients who received IMPT versus IMRT. CONCLUSIONS: Studies have proposed that proton's greater relative biological effectiveness at the Bragg peak could lead to tissue inflammation. Our study did not corroborate these findings. This study's conclusion underscores the need for further investigations with ultimate correlation with clinical toxicity outcomes.

Hypoxia-Directed Treatment of Human Papillomavirus-Related Oropharyngeal Carcinoma.

PURPOSE: Standard curative-intent chemoradiotherapy for human papillomavirus (HPV)-related oropharyngeal carcinoma results in significant toxicity. Since hypoxic tumors are radioresistant, we posited that the aerobic state of a tumor could identify patients eligible for de-escalation of chemoradiotherapy while maintaining treatment efficacy. METHODS: We enrolled patients with HPV-related oropharyngeal carcinoma to receive de-escalated definitive chemoradiotherapy in a phase II study (ClinicalTrials.gov identifier: NCT03323463). Patients first underwent surgical removal of disease at their primary site, but not of gross disease in the neck. A baseline 18F-fluoromisonidazole positron emission tomography scan was used to measure tumor hypoxia and was repeated 1-2 weeks intratreatment. Patients with nonhypoxic tumors received 30 Gy (3 weeks) with chemotherapy, whereas those with hypoxic tumors received standard chemoradiotherapy to 70 Gy (7 weeks). The primary objective was achieving a 2-year locoregional control (LRC) of 95% with a 7% noninferiority margin. RESULTS: One hundred fifty-eight patients with T0-2/N1-N2c were enrolled, of which 152 patients were eligible for analyses. Of these, 128 patients met criteria for 30 Gy and 24 patients received 70 Gy. The 2-year LRC was 94.7% (95% CI, 89.8 to 97.7), meeting our primary objective. With a median follow-up time of 38.3 (range, 22.1-58.4) months, the 2-year progression-free survival (PFS) and overall survival (OS) rates were 94% and 100%, respectively, for the 30-Gy cohort. The 70-Gy cohort had similar 2-year PFS and OS rates at 96% and 96%, respectively. Acute grade 3-4 adverse events were more common in 70 Gy versus 30 Gy (58.3% v 32%; P = .02). Late grade 3-4 adverse events only occurred in the 70-Gy cohort, in which 4.5% complained of late dysphagia. CONCLUSION: Tumor hypoxia is a promising approach to direct dosing of curative-intent chemoradiotherapy for HPV-related carcinomas with preserved efficacy and substantially reduced toxicity that requires further investigation.

Automated full body tumor segmentation in DOTATATE PET/CT for neuroendocrine cancer patients.

PURPOSE: Neuroendocrine tumors (NETs) are a rare form of cancer that can occur anywhere in the body and commonly metastasizes. The large variance in location and aggressiveness of the tumors makes it a difficult cancer to treat. Assessments of the whole-body tumor burden in a patient image allow for better tracking of disease progression and inform better treatment decisions. Currently, radiologists rely on qualitative assessments of this metric since manual segmentation is unfeasible within a typical busy clinical workflow. METHODS: We address these challenges by extending the application of the nnU-net pipeline to produce automatic NET segmentation models. We utilize the ideal imaging type of 68Ga-DOTATATE PET/CT to produce segmentation masks from which to calculate total tumor burden metrics. We provide a human-level baseline for the task and perform ablation experiments of model inputs, architectures, and loss functions. RESULTS: Our dataset is comprised of 915 PET/CT scans and is divided into a held-out test set (87 cases) and 5 training subsets to perform cross-validation. The proposed models achieve test Dice scores of 0.644, on par with our inter-annotator Dice score on a subset 6 patients of 0.682. If we apply our modified Dice score to the predictions, the test performance reaches a score of 0.80. CONCLUSION: In this paper, we demonstrate the ability to automatically generate accurate NET segmentation masks given PET images through supervised learning. We publish the model for extended use and to support the treatment planning of this rare cancer.

FDG PET/CT imaging features and clinical utility in COVID-19.

PURPOSE: To determine the imaging findings and potential clinical utility of FDG PET/CT in patients with laboratory-confirmed COVID-19. METHODS: We performed a single institution retrospective review of patients diagnosed with COVID-19 using real time reverse transcription-polymerase chain reaction (RT-PCR) who underwent FDG PET/CT for routine cancer care between March 1, 2020 to April 30, 2020, during the height of the pandemic in New York City, New York, United States. PET/CT scans were retrospectively reviewed for imaging findings suspicious for COVID-19. For positive scans, PET and CT findings were recorded, including location, FDG avidity (SUVmax) and CT morphology. Patient demographics and COVID-19 specific clinical data were collected and analyzed with respect to PET/CT scan positivity, lung SUVmax, and time interval between PET/CT and RT-PCR. RESULTS: Thirty-one patients (21 males and 10 females, mean age 57 years ± 16) were evaluated. Thirteen of 31 patients had positive PET/CT scans, yielding a detection rate of 41.9%. Patients with positive scans had significantly higher rates of symptomatic COVID-19 infection (77% vs 28%, p = 0.01) and hospitalizations (46% vs. 0%, p = 0.002) compared to patients with negative scans. Eleven of 13 patients (84.6%) with positive scans had FDG-avid lung findings, with mean lung SUVmax of 5.36. Six of 13 patients (46.2%) had extrapulmonary findings of FDG-avid thoracic lymph nodes. The detection rate was significantly lower when the scan was performed before RT-PCR versus after RT-PCR (18.8% (n = 3/16) vs. 66.7% (n = 10/15), p = 0.009). Lung SUVmax was not associated with COVID-19 symptoms, severity, or disease course. CONCLUSION: FDG PET/CT has limited sensitivity for detecting COVID-19 infection. However, a positive PET scan is associated with higher risk of symptomatic infection and hospitalizations, which may be helpful in predicting disease severity.

A physics-guided modular deep-learning based automated framework for tumor segmentation in PET.

An important need exists for reliable positron emission tomography (PET) tumor-segmentation methods for tasks such as PET-based radiation-therapy planning and reliable quantification of volumetric and radiomic features. To address this need, we propose an automated physics-guided deep-learning-based three-module framework to segment PET images on a per-slice basis. The framework is designed to help address the challenges of limited spatial resolution and lack of clinical training data with known ground-truth tumor boundaries in PET. The first module generates PET images containing highly realistic tumors with known ground-truth using a new stochastic and physics-based approach, addressing lack of training data. The second module trains a modified U-net using these images, helping it learn the tumor-segmentation task. The third module fine-tunes this network using a small-sized clinical dataset with radiologist-defined delineations as surrogate ground-truth, helping the framework learn features potentially missed in simulated tumors. The framework was evaluated in the context of segmenting primary tumors in 18F-fluorodeoxyglucose (FDG)-PET images of patients with lung cancer. The framework's accuracy, generalizability to different scanners, sensitivity to partial volume effects (PVEs) and efficacy in reducing the number of training images were quantitatively evaluated using Dice similarity coefficient (DSC) and several other metrics. The framework yielded reliable performance in both simulated (DSC: 0.87 (95% confidence interval (CI): 0.86, 0.88)) and patient images (DSC: 0.73 (95% CI: 0.71, 0.76)), outperformed several widely used semi-automated approaches, accurately segmented relatively small tumors (smallest segmented cross-section was 1.83 cm2), generalized across five PET scanners (DSC: 0.74 (95% CI: 0.71, 0.76)), was relatively unaffected by PVEs, and required low training data (training with data from even 30 patients yielded DSC of 0.70 (95% CI: 0.68, 0.71)). In conclusion, the proposed automated physics-guided deep-learning-based PET-segmentation framework yielded reliable performance in delineating tumors in FDG-PET images of patients with lung cancer.

Adapting a Standardized, Industry-Proven Tool to Measure Patients' Perceptions of Quality at the Point of Care in a PET/CT Center.

Patient satisfaction with health-care delivery is essential today. Using a psychometrically validated questionnaire-SERVPERF-we quantitatively measured patients' perceptions of the quality of service at the point of care in a PET/CT center, and we used this information to guide subsequent quality improvement interventions. SERVPERF is a survey instrument that measures performance for various services. It has demonstrated reliability and validity across various industries. The standard for measuring patient perception of quality in hospitals-the "Hospital Consumer Assessment of Health Care Providers and Systems" survey-does not include questions about the care received in a typical radiology department and is not performed at the point of care. Methods: 429 patients undergoing PET/CT examinations filled out an anonymous modified SERVPERF questionnaire on completion of imaging and reported their level of agreement with each of the 27 items by circling a Likert-type scale from 1 to 7. Each item was designed to elicit a response on the patient's perception of performance on a metric of quality. Data were summarized as the mean of each item. The frequency of low scores (≤3) was also calculated. Results: The items with the lowest mean score were "The department's physical facilities are visually appealing" (6.158) and "Documentation such as sign-in sheet, handouts, and brochures are visually appealing" (6.162). The item with the highest frequency of low scores (≤3) was, "The department provides services at the promised time" (11/429 responses). Conclusion: Our study showed that patient perception of quality in a diagnostic radiology department can be measured with a standardized survey at the point of care delivery and used to direct patient-centered quality improvement interventions.

JOURNAL CLUB: Value of Quantitative FDG PET/CT Volumetric Biomarkers in Recurrent Colorectal Cancer Patient Survival.

OBJECTIVE: The purpose of this study was to evaluate the impact of quantitative PET parameters in the overall survival of patients with recurrent colorectal cancer. MATERIALS AND METHODS: A total of 105 patients with a biopsy-proven recurrence of colorectal cancer who underwent PET/CT were included in the study. A gradient segmentation method was used to calculate maximum and peak standardized uptake values (SUVmax, SUVpeak), total lesion glycolysis (TLGtotal), and metabolic tumor volume (MTVtotal). These parameters were measured for each recurrent lesion at the primary, locoregional, and distant sites. The median follow-up time was 31.3 months. Overall survival (OS) was the primary outcome and was calculated using Kaplan-Meier survival plots and Cox regression analyses. RESULTS: The mean ± SD for SUVmax, SUVpeak, TLGtotal, and MTVtotal of the included patients was 7.3 ± 5.3, 5.3 ± 3.3, 280.8 ± 1181 g, and 79.8 ± 294 mL, respectively. The median OS for patients who were alive was 50 months in comparison with 23.4 months among patients who died. Age (p = 0.041), tumor grade (p = 0.010), median TLG (p = 0.031), and median MTV (p = 0.009) remained significantly associated with OS in the multivariate Cox regression analysis. Kaplan-Meier survival analysis performed on the basis of the median PET/CT parametric values showed that SUVmax (threshold, 5.63; hazard ratio [HR] = 1.7; 95% CI, 1-2.8; p = 0.02), MTVtotal (threshold, 13.85 mL; HR = 2.2; 95% CI, 1.3-3.9; p = 0.003), and TLGtotal (threshold, 36.14 g; HR = 1.9; 95% CI, 1.1-3.3; p = 0.01) were significant predictors of OS during follow-up. An integrated risk stratification model with SUVmax and MTVtotal into three subgroups predicted patient survival outcomes (HR = 1.8; 95% CI, 1.25-2.65; log-rank p = 0.003). CONCLUSION: SUVmax, MTVtotal, TLGtotal, and integrated score with FDG avidity and total tumor burden provide survival information for patients with biopsy-proven recurrent colorectal cancer.

Therapy Response Assessment and Patient Outcomes in Head and Neck Squamous Cell Carcinoma: FDG PET Hopkins Criteria Versus Residual Neck Node Size and Morphologic Features.

OBJECTIVE: This study investigates the prognostic value of (18)F-FDG PET/CT qualitative therapy assessment (Hopkins criteria) in patients with head and neck squamous cell carcinomas (HNSCCs) with residual neck nodes after definitive chemoradiation therapy and compares the Hopkins criteria with anatomic nodal size and morphologic features for prediction of survival outcomes. MATERIALS AND METHODS: A total of 72 patients with HNSCC, with negative primary tumor and positive residual neck nodes (CT criteria > 1 cm short-axis diameter) after the completion of definitive chemoradiation therapy, were included. PET/CT was performed 6-24 weeks after completion of treatment. FDG uptake in residual nodes on PET/CT was interpreted using a structured qualitative 5-point scale (Hopkins criteria). The 5-point scale was dichotomized to negative (scores 1, 2, and 3) or positive (scores 4 and 5) results. Cystic or necrotic nodes were defined as those with central low attenuation with a relatively hyperdense capsule. Kaplan-Meier curve and Cox regression analysis were performed. RESULTS: On the basis of the Hopkins criteria, 10 (13.9%) patients had positive findings and 62 (86.1%) had negative findings for residual nodal disease. According to CT interpretation, 25 patients (34.7%) had residual cervical lymph nodes greater than or equal to 1.5 cm in diameter, and 41 (56.9%) patients had cystic or necrotic nodes. Patients were followed for a median of 27 months after posttherapy PET/CT. There was a statistically significant difference in overall survival (OS) (hazard ratio, 7.06; p < 0.001) and progression-free survival (PFS) (hazard ratio, 6.18; p < 0.001) between patients with negative versus positive residual FDG nodal uptake. There was no statistically significant difference in OS and PFS in patients categorized on the basis of nodal size or morphologic features. CONCLUSION: PET-based structured qualitative therapy assessment (Hopkins criteria) can predict survival outcomes of patients with HNSCC with residual neck nodes after definitive chemoradiotherapy.

FDG PET/CT in Patients With Head and Neck Squamous Cell Carcinoma After Primary Surgical Resection With or Without Chemoradiation Therapy.

OBJECTIVE: The purpose of this study was to assess the value of posttreatment FDG PET/CT in patients with squamous cell carcinoma of the head and neck (HNSCC) treated with primary surgical resection with or without adjuvant concurrent chemoradiotherapy. MATERIALS AND METHODS: A total of 98 HNSCC patients were treated with primary surgical resection and had undergone PET/CT within 6 months of treatment completion. The accuracy of the scans and the added value to clinical assessment and impact on management were established based on the clinical information before and after each scan. Overall survival of patients was estimated with Kaplan-Meier curves. RESULTS: Of the total 98 scans, 25 (25.5%) were interpreted as positive and 73 (74.5%) as negative. The sensitivity of posttreatment PET/CT was 80.0%; specificity, 89.5%; positive predictive value, 66.7%; negative predictive value, 94.4%; and accuracy, 87.5%. These scans were helpful in excluding tumor in 31.8% of patients with clinical suspicion of residual disease and identifying suspected residual disease in 13.2% of patients with no prior clinical suspicion. Multivariate regression analysis showed that tumor size, grade (p = 0.041), scan type (p = 0.002), and scan result (p = 0.005) were independent covariates associated with overall survival. Kaplan-Meier analysis showed a significant difference and association in overall survival between patients with a positive versus a negative posttherapy PET/CT scan result (hazard ratio, 5.65; 95% CI, 2.48-12.83; log rank Mantel-Cox p < 0.001). CONCLUSION: Posttreatment FDG PET/CT results had a high negative predictive value, added value to clinical assessment of 35% of patients, influenced subsequent management, and were associated with survival outcome of HNSCC patients treated with primary surgical resection.

FDG Avidity and Tumor Burden: Survival Outcomes for Patients With Recurrent Breast Cancer.

OBJECTIVE: The objective of this study was to assess the value of quantitative PET parameters in the prediction of survival for patients with recurrent breast cancer. MATERIALS AND METHODS: We conducted a retrospective study of 78 women who had recurrent breast cancer identified by biopsy or follow-up examinations from 2000 to 2012. The maximum and peak standardized uptake values (SUVmax and SUVpeak, respectively), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured for each recurrent lesion at primary, nodal, and distant metastatic sites, with the use of the gradient segmentation method. The optimum cutoff point (i.e., the value with the maximum Youden index, defined as sensitivity plus specificity minus 1) was calculated using the ROC curve. The median follow-up duration was 28.5 months (range, 0-94 months). The primary outcome measure was overall survival (OS). Kaplan-Meier survival plots and Cox regression analyses were performed. RESULTS: The mean (± SD) values noted for the study population were as follows: an SUVmax of 6.70 ± 4.1, an SUVpeak of 5.12 ± 3.4, total lesion glycolysis of all recurrent lesions (TLGtotal) of 359.73 ± 1114.4 g, and metabolic tumor volume of all recurrent lesions (MTVtotal) of 68.04 ± 144.9 mL. The mean OS for patients who died was 25.5 months, whereas for patients who survived, it was 36.7 months (p = 0.04). Univariate analysis showed that age (p = 0.02), optimum SUVmax (p = 0.006), SUVpeak (p = 0.006), and TLGtotal (p = 0.034) were associated with OS; however, none of the factors remained statistically significant in multivariate analysis. Kaplan-Meier survival analysis was performed, and the SUVmax (threshold, 2.9; hazard ratio [HR], 5.2 [95% CI, 1.6-16.7]; p = 0.002), SUVpeak (threshold, 2.34; HR, 4.3 [95% CI, 1.5-12]; p = 0.002), and TLG (threshold, 11.85 g; HR, 2.8 [95% CI, 1.0-7.1]; p = 0.025) were statistically significant predictors of death during follow-up. An integrated risk stratification model with FDG avidity (SUVmax) and MTVtotal divided into three subgroups of patients predicted patient survival outcomes (HR, 2.48 [95% CI, 1.38-4.46]; p = 0.005, by log-rank test). CONCLUSION: FDG PET-determined SUVmax, SUVpeak, and TLG values and an integrated risk stratification scheme using FDG avidity and total tumor burden appear to provide prognostic survival information for patients with recurrent breast cancer.

18F-FDG PET/CT: Therapy Response Assessment Interpretation (Hopkins Criteria) and Survival Outcomes in Lung Cancer Patients.

UNLABELLED: The purpose of this study was to evaluate the value of an (18)F-FDG PET/CT-based interpretation system (Hopkins criteria) to assess the therapy response and survival in lung cancer. METHODS: This is an Institutional Review Board-approved, retrospective study. A total of 201 patients with biopsy-proven lung cancer, who underwent therapy assessment (18)F-FDG PET/CT within 6 mo (mean, 7.5 wk) of completion of treatment, were included. Patients were primarily treated with surgical resection, chemotherapy, radiation therapy, or a combination of these treatments. PET/CT studies were interpreted by 2 nuclear medicine physicians, and discrepancies were resolved by a third interpreter. The studies were scored using a qualitative 5-point scale for the primary tumor, mediastinum, distant metastatic site, if present, and overall assessment. Scores 1, 2, and 3 were considered negative and scores 4 and 5 were considered positive for residual disease. Patients were followed for a median of 12 mo (up to 128 mo). Kaplan-Meier plots with a Mantel-Cox log-rank test were performed considering death as the endpoint. RESULTS: Overall, the PET/CT studies were positive in 144 (71.6%) and negative in 57 (28.4%) patients. There was substantial agreement between 2 interpreters (R1, R2), with a κ of 0.78 (P < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the Hopkins scoring system were 89%, 80%, 92.8%, 71.4%, and 86.7%, respectively. Overall, PET/CT resulted in starting a new treatment plan in 70.8% of patients with positive residual disease on therapy assessment PET/CT. There was a significant difference in overall survival (OS) between patients who were categorized as positive in comparison to those who were categorized as negative (hazard ratio [HR] = 2.12; 95% confidence interval = 1.44-3.12), which remained significant after adjustment for disease stage, prior clinical suspicion, and primary treatment. Subgroup analysis according to the tumor histology showed that positive Hopkins scoring could significantly predict the OS in both small cell lung cancer (HR = 2.88; log-rank, P = 0.02) and non-small cell lung cancer (HR = 2.01; log-rank, P = 0.001). Similarly, there was a significant difference in OS between patients with positive and negative Hopkins score both in those who had surgical resection as part of the primary treatment (HR = 6.09; log-rank, P < 0.001) and in those who were treated with chemotherapy with or without radiation (HR = 1.60; log-rank, P = 0.02). CONCLUSION: The 5-point qualitative therapy response interpretation for lung cancer has substantial interinterpreter agreement and high accuracy and could significantly predict survival in lung cancer, irrespective of tumor histology and treatment modality.

18F-FDG-PET/CT therapy assessment of locally advanced pancreatic adenocarcinoma: impact on management and utilization of quantitative parameters for patient survival prediction.

OBJECTIVES: This study aims to evaluate the impact of therapy assessment PET/computed tomography (CT) scan on the management of locally advanced pancreatic adenocarcinoma (LAPC), and the value of qualitative versus quantitative PET/CT interpretation for patient outcome prediction. MATERIALS AND METHODS: Forty-two LAPC patients were retrospectively included. PET/CT was performed at a median of 4.6 weeks after completion of chemo ± radiotherapy to assess the primary treatment response. PET was interpreted visually using a qualitative five-point scale (Hopkins criteria for therapy assessment). Quantitative PET parameters including maximum and peak standardized uptake value (SUV max and SUV peak), total lesion glycolysis, and metabolic tumor volume (MTV) were also measured using the gradient segmentation method. Kaplan-Meier and Cox regression analyses were performed. RESULTS: Thirty-five patients were followed up until death. Therapy assessment PET/CT led to a change in the overall management of 22 (52.4%) patients, prompting surgical resection (eight patients), adding radiation therapy (eight patients), or starting palliative chemotherapy (six patients). The median survival in patients with a negative or a positive PET scan, according to the Hopkins criteria, was 14.6 and 8.7 months, respectively (P=0.06). The median quantitative thresholds of SUV peak 2.64 [hazard ratio (HR)=2.67, P=0.03], total lesion glycolysis 44.0 g (HR=2.64, P=0.005), and MTV 24.7 ml (HR=2.57, P=0.008) were significant predictors of overall survival. Using combined quantitative scoring, patients with high SUV peak and high MTV (>median cut point) had a 5.45-fold (95% confidence interval: 1.76-16.87) increased risk for death compared with those with both low SUV peak and MTV (the reference group). CONCLUSION: PET-based volumetric parameters can predict survival outcomes of patients with LAPC. A combined quantitative PET/CT scoring system provides significantly improved prognostication.

Impact of point spread function reconstruction on quantitative 18F-FDG-PET/CT imaging parameters and inter-reader reproducibility in solid tumors.

INTRODUCTION: This study aims to determine the impact of point-spread function (PSF) reconstruction on quantitative PET/computed tomography (CT) indices and the inter-reader reproducibility of these measurements. MATERIALS AND METHODS: The study was approved by the Institutional Review Board under a waiver of informed consent. A total of 42 oncology patients with 85 lesions (all ≥ 2 cm) were included. The PET/CT images were reconstructed with PSF (OSEM+TOF, 2i, 21s, all-pass filter) and without PSF (OSEM+TOF, 2i, 21s, 5 mm Gaussian). For each lesion, the maximum, mean, and peak standardized uptake values (SUV), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) were measured by two readers (R1 and R2) using a semiautomatic gradient segmentation method. Intraclass correlation coefficient (ICC) and Bland-Altman analyses were performed. RESULTS: There was excellent correlation between non-PSF and PSF reconstruction PET/CT values (ICC ≥ 0.96 for all parameters, P < 0.0001). Comparison of PSF with non-PSF images showed a mean bias (percentage change) of +11.97% (R1) and +11.94% (R2) for SUV max, +7.63% (R1) and +7.82% (R2) for SUV mean, +7.45% (R1) and +7.37% (R2) for SUV peak, -0.82% (R1) and -0.1% (R2) for TLG, and -6.68% (R1) and -5.65% (R2) for MTV. PSF reconstruction resulted in a decrease in MTV in 77.6% (R1) and 83.5% (R2) of lesions. Percentage changes in PSF versus non-PSF indices were not related to the site of the lesions (P > 0.05). Close agreement was observed between two readers (ICC ranged between 0.9 and 1.0, P < 0.0001). CONCLUSION: The PSF reconstruction increased the SUV max, SUV mean, and SUV peak, as expected, whereas it tended to produce lower values for MTV and had variable effect on TLG. This can be attributed to the ability of PSF reconstruction to better discern tumor uptake from activity spill-out.

(18)F-Flourodeoxy-Glucose PET/Computed Tomography in Brain Tumors: Value to Patient Management and Survival Outcomes.

(18)F-flourodeoxy-glucose (FDG) PET/computed tomography (CT) is most useful in the evaluation of primary central nervous system (CNS) lymphoma, important in diagnosis, pretherapy prognosis, and therapy response evaluation. Utility in working up gliomas is less effective, and FDG PET/CT is most helpful when MR imaging is unclear. FDG avidity correlates with the grade of gliomas. FDG PET/CT can be used to noninvasively identify malignant transformation. Establishing this change in the disease process has significant effects on patient management and survival outcome.

Nosocomial transmission of group B streptococci proven by positive environmental culture.

OBJECTIVE: Neonates usually acquire Group B streptococcal infection vertically from the maternal birth canal during delivery. In January 2010, a Group B streptococcal outbreak investigation was conducted in response to an increased number of clinical specimens from our neonatal intensive care unit. METHODS: Microbiology laboratory records were reviewed to identify Group B streptococcal from specimens originating from the neonatal intensive care unit during December 2009 and January 2010. Patients from whom these specimens were collected were identified and their charts reviewed. Environmental samples to screen for Group B streptococcal were collected from the unit, clinical and environmental isolates were compared by pulsed field gel electrophoresis. Point prevalence screening was conducted twice before declaring the outbreak over. RESULTS: Pulsed field gel electrophoresis patterns of three clinical strains from six patients were indistinguishable. One environmental strain was isolated from one of the patients monitor, and had identical pulsed field gel electrophoresis pattern to that of the three clinical strains. Infection control measures were implemented in the neonatal intensive care unit and follow-up point prevalence screening identified no new cases. CONCLUSIONS: Although poor infection control practice has been implicated in previous reports of nosocomial outbreaks of Group B streptococcal infection in neonatal intensive care units, our finding provides unique evidence that the environment can act as a reservoir of Group B streptococcal and play a key role in nosocomial transmission.

Partial splenic embolisation using n-butyl cyanoacrylate: intraprocedural evaluation by magnetic resonance imaging.

OBJECTIVES: To evaluate the use of diffusion-weighted imaging (DWI) for estimating infarcted splenic volume during partial splenic embolisation (PSE) using n-butyl cyanoacrylate (NBCA). METHODS: Twenty consecutive patients (57.2 ± 11.7 years) with hypersplenism underwent PSE. Intrasplenic branches were embolised using NBCA via a 2.1-French microcatheter aiming at infarction of 50 to 80 % of total splenic volume. Immediately after PSE, signal intensities (SI) of embolised and non-embolised splenic parenchyma were measured on DWI. Semi-automated volumetry (SAV) on DWI was compared with conventional manual volumetry (MV) on contrast-enhanced CT 1 week after PSE. Platelet counts were recorded before and after PSE. RESULTS: The SI on DWI in the embolised parenchyma decreased significantly (P < 0.01) to 24.7 ± 8.1 % as compared to non-embolised parenchyma. SAV and MV showed a strong correlation (r = 0.913 before PSE, r = 0.935 after PSE, P < 0.01) and significant (P < 0.01) reduction of normal splenic volume was demonstrated on both SAV (71.9 ± 12.4 %) and MV (73.6 ± 9.3 %) after PSE. Based on the initial SAV, three patients (15 %) underwent additional branch embolisation to reach sufficient infarction volume. Platelet counts elevated significantly (522.8 ± 209.1 %, P < 0.01) by 2 weeks after PSE. No serious complication was observed. CONCLUSION: Immediate SI changes on DWI after PSE allowed semi-automated splenic volumetry on site. KEY POINTS: • Partial splenic embolisation (PSE) is an important interventional technique for hypersplenism • Diffusion-weighted MR reveals an immediate decrease in signal in the embolised parenchyma • Such signal reduction permits semi-automated splenic volumetry on site. • This allows precise quantification of the amount of parenchyma infarcted, avoiding additional PSE.

Very low-activity stress/high-activity rest, single-day myocardial perfusion SPECT with a conventional sodium iodide camera and wide beam reconstruction processing.

BACKGROUND: A stress (S)/rest (R) 1-day Tc-99m sestamibi protocol is logistically advantageous and facilitates stress-only imaging. However, with conventional 370 MBq (10 mCi) S activity and subsequent 1,110-1,295 MBq (30-35 mCi) R activity there is a risk of S-to-R "shine-through" and underestimation of defect reversibility. New software methods cope with lower counting statistics and should allow for both a reduced S activity and also less likelihood of S-to-R "shine-through." METHODS: 102 prospective patients [49 men, 53 women; mean weight 178 ± 41 lbs (range 98-265 lbs); chest 41.5″ ± 4.0″ (range 32″-52″)] received 192.4 + 18.5 MBq (5.2 ± 0.5 mCi) Tc-99m sestamibi S (25 exercise, 77 regadenoson) activity followed in 30-40 minutes by "full-time" (12 minutes) two-headed NaI camera S SPECT. Immediately thereafter, a 16-minute S SPECT acquisition was also performed in 37/102 patients. Then at 60-80 minute post-S all patients received 1328.3 + 129.5 MBq (35.9 ± 3.5 mCi) Tc-99m sestamibi, and "half-time" (7.5 minutes) R SPECT was acquired. All tomograms were processed with wide beam reconstruction (WBR, UltraSPECT Ltd.) software. A time-adjusted R/S myocardial count density ratio (MCDR) was calculated using automated software. S SPECT quality was visually graded (poor, fair, good, excellent) based upon myocardial definition, cavity contrast, RV visualization, and noise. For comparison, the S/R MCDR was calculated in 581 consecutive patients undergoing a conventional 370 MBq R/1110 MBq S (10 mCi R/30 mCi S) protocol. RESULTS: S SPECT was normal in 44 patients (43%). Image quality was good-excellent in 93 (91%) patients with 12-minute S SPECT. Also in 37 (98%) patients with 16-minute S SPECT, quality was good-excellent. In patients with >42″ chests 12-minute S SPECT quality worsened with increasing chest circumference, manifested by myocardial "blurring." Image quality improved by ≥1 grade in the 12/37 patients (32%) also undergoing 16-minute S SPECT. The time- and decay-corrected 12-minute mean R/S MCDR was 5.78, a ratio adequate to minimize S-to-R shine-through, as verified in phantom experiments, and significantly better than a 3.79 S/R ratio achieved in the 581 patients undergoing a conventional R/S protocol. CONCLUSIONS: An approximately 185 MBq (5 mCi S) Tc-99m SPECT processed with WBR provides adequate image quality. For larger patients prolonging image acquisition to 16 minutes is beneficial. For patients with normal S SPECT, a S-only protocol is feasible, affording them a very low (approximately 1.4 mSv) radiation dose. If subsequent R SPECT is necessary, it can be performed with approximately 1,332 MBq (36 mCi) with minimal S-R "shine-through."

Attitudes and beliefs, not just knowledge, influence the effectiveness of environmental cleaning by environmental service workers.

BACKGROUND: Hospital environmental service workers (ESWs) play an important role in interrupting the chain of infection because the environment is a reservoir for nosocomial pathogens. Improving ESWs' knowledge through education has been shown to improve ESW cleaning, but the behavioral determinants of their work have not been studied. Understanding and targeting ESWs' attitudes and beliefs may inform strategies to improve environmental cleaning. METHODS: With the theory of planned behavior as framework, we used questionnaires and focus groups to examine intensive care unit ESWs' attitudes, beliefs [behavioral, normative, and control], and control) and intent about their job. Baseline quantitative microbial cultures of high-touch services were performed before and after cleaning. After an educational intervention addressing their attitudes, beliefs, and general infection control knowledge, attitudes, beliefs, and microbial contamination were reassessed. RESULTS: Beliefs were uniformly strong (4.5/5-5/5), and normative beliefs correlated best with intent to clean (R(2) = 0.3). Themes elicited from the focus groups included "me versus them," lack of appreciation, pride in work, and "if it were me." The rate of environmental contamination was significantly improved after the intervention (P = .0074 vs P = .0023, respectively); the measured relationship among attitudes, beliefs, and intent was not significantly changed. CONCLUSION: ESWs' attitudes and beliefs about their job may impact their intent to clean and in turn the effectiveness of their efforts. Understanding and addressing these attitudes and beliefs can be used to inform strategies for sustained improvement of environmental cleaning.

Improving patient safety through a multi-faceted internal surveillance program.

Surveillance, a method used in epidemiology to study the incidence, distribution and control of disease, is an important means of gathering and analyzing information that can be used as needed to effect change. Surveillance has been an important component of the Blueprint for Patient Safety at the Hospital for Sick Children to identify potential and existing vulnerabilities and failures and put measures in place to avoid and mitigate any harm. Reviewing internal reports and actively seeking vulnerabilities has allowed us to make important changes to improve patient safety at the hospital. In this article, we review four internal surveillance strategies that have been particularly successful in driving change - safety reports, morbidity and mortality reviews, patient safety walkarounds and shoe leather infection control rounds - and discuss the successes and challenges we have experienced.