JOURNAL CLUB: CT Dose Optimization for Whole-Body PET/CT Examinations

Summary:Clinical studies demonstrate a gain in diagnostic accuracy by employing combined PET/CT instead of separate CT and PET imaging. However, whole-body PET/CT examinations result in a comparatively high radiation burden to patients and thus require a proper justification and optimization to avoid repeated exposure or over-exposure of patients. This review article summarizes relevant data concerning radiation exposure of patients resulting from the different components of a combined PET/CT examination and presents different imaging strategies that can help to balance the diagnostic needs and the radiation protection requirements. In addition various dose reduction measures are discussed, some of which can be adopted from CT practice, while others mandate modifications to the existing hardand software of PET/CT systems.

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Reducing [ 18 F]FDG activity levels for whole-body PET/CT examinations of children

10.1055/s-0040-1708302 ◽

2020 ◽

Author(s):

H Kertesz ◽

T Beyer ◽

T Traub-Weidinger ◽

J Cal-Gonzalez ◽

M Hacker ◽

...

Keyword(s):

Whole Body ◽

Activity Levels ◽

Pet Ct

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Whole-Body PET-CT

e-Anatomy ◽

10.37019/e-anatomy/159099 ◽

2008 ◽

Author(s):

Antoine Micheau ◽

Denis Hoa

Keyword(s):

Whole Body ◽

Pet Ct

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PET/CT WITH 68GA-PSMA-11 IN DETECTION OF PRIMARY TUMOR AND RECURRENCE OF PROSTATE CANCER

Problems in oncology ◽

10.37469/0507-3758-2018-64-6-799-804 ◽

2018 ◽

Vol 64 (6) ◽

pp. 799-804

Author(s):

Darya Ryzhkova ◽

M. Poyda

Keyword(s):

Prostate Cancer ◽

Primary Tumor ◽

Biochemical Recurrence ◽

Whole Body ◽

Negative Results ◽

Primary Prostate Cancer ◽

Pet Ct ◽

The Relationship ◽

Positive Results ◽

T Category

Purpose: To study the diagnostic value of PET-CT with 68Ga-PSMA-11 in the diagnosis of a primary prostate cancer, preoperative staging, and the detection of recurrence of prostate cancer (PCa). Methods: 28 patients aged 64.7 ± 8.74 years were included. 10 patients primary prostate cancer, and 18 patients with biochemical recurrence of the disease after radical treatment were examined. All patients underwent PET-CT with 68Ga-PSMA-11 according the whole body protocol. Interpretation of images was performed visually and quantitatively by calculation of SUL max. Results: High focal or diffuse 68Ga-PSMA-11 uptake was found in prostate parenchyma in patients with primary prostate cancer. Additionally metastases in regional lymph nodes were diagnosed in 4 patients and bone metastases were found in one patient. The correlation between 68Ga-PSMA-11 uptake level and Gleason index in the primary tumor (R Spearmen = 0.25, p = 0.57) was not observed. PET-positive results were obtained in 14 patients and PET-negative results in 4 patients with biochemical recurrence of PCa. The relationship between the frequency of PET-positive results and Gleason index was not revealed (R Spearmen = 0.2, p = 0.39). We found a weak but significant correlation between the frequency of PET-positive results and the prostate tumor stage according to the T category (R Spearmen = 0.49, p = 0.049). In patients with low values of PSA (less than 1.0 ng/ml) in 4 out of 9 cases, PET-negative results were obtained. In patients with PSA level more than 1.0 ng/ml PET-positive results were obtained in all cases. Conclusions: PET/CT with 68Ga-PSMA-11 allows to diagnose the primary prostate cancer, to establish the stage of the disease in categories N and M, and also to determine the localization and dissemination of the tumor in patients with biochemical recurrence of prostate cancer. The relationship between 68Ga-PSMA-11 uptake in primary tumor and Gleason index was not found. The probability of obtaining PET-positive results in cases of biochemical recurrence is affected by a PSA level above 1 ng/ml and a high stage of the disease according to the T category (T3-T4).

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Prospective study of dynamic whole-body 68Ga-DOTATOC-PET/CT acquisition in patients with well-differentiated neuroendocrine tumors

Scientific Reports ◽

10.1038/s41598-021-83965-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Philippe Thuillier ◽

David Bourhis ◽

Jean Philippe Metges ◽

Romain Le Pennec ◽

Karim Amrane ◽

...

Keyword(s):

Neuroendocrine Tumors ◽

Linear Relation ◽

Whole Body ◽

Pet Ct ◽

Non Linear ◽

Well Differentiated ◽

Analog Systems ◽

Pet System ◽

Dynamic Acquisition ◽

Linear Regressions

AbstractTo present the feasibility of a dynamic whole-body (DWB) 68Ga-DOTATOC-PET/CT acquisition in patients with well-differentiated neuroendocrine tumors (WD-NETs). Sixty-one patients who underwent a DWB 68Ga-DOTATOC-PET/CT for a histologically proven/highly suspected WD-NET were prospectively included. The acquisition consisted in single-bed dynamic acquisition centered on the heart, followed by the DWB and static acquisitions. For liver, spleen and tumor (1–5/patient), Ki values (in ml/min/100 ml) were calculated according to Patlak's analysis and tumor-to-liver (TLR-Ki) and tumor-to-spleen ratios (TSR-Ki) were recorded. Ki-based parameters were compared to static parameters (SUVmax/SUVmean, TLR/TSRmean, according to liver/spleen SUVmean), in the whole-cohort and according to the PET system (analog/digital). A correlation analysis between SUVmean/Ki was performed using linear and non-linear regressions. Ki-liver was not influenced by the PET system used, unlike SUVmax/SUVmean. The regression analysis showed a non-linear relation between Ki/SUVmean (R2 = 0.55,0.68 and 0.71 for liver, spleen and tumor uptake, respectively) and a linear relation between TLRmean/TLR-Ki (R2 = 0.75). These results were not affected by the PET system, on the contrary of the relation between TSRmean/TSR-Ki (R2 = 0.94 and 0.73 using linear and non-linear regressions in digital and analog systems, respectively). Our study is the first showing the feasibility of a DWB 68Ga-DOTATOC-PET/CT acquisition in WD-NETs.

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Multi-task weak supervision enables anatomically-resolved abnormality detection in whole-body FDG-PET/CT

Nature Communications ◽

10.1038/s41467-021-22018-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Sabri Eyuboglu ◽

Geoffrey Angus ◽

Bhavik N. Patel ◽

Anuj Pareek ◽

Guido Davidzon ◽

...

Keyword(s):

Fdg Pet ◽

Location Estimation ◽

Supervised Machine Learning ◽

Whole Body ◽

Free Text ◽

Abnormality Detection ◽

Weak Supervision ◽

Radiology Reports ◽

Pet Ct ◽

Fdg Pet Ct

AbstractComputational decision support systems could provide clinical value in whole-body FDG-PET/CT workflows. However, limited availability of labeled data combined with the large size of PET/CT imaging exams make it challenging to apply existing supervised machine learning systems. Leveraging recent advancements in natural language processing, we describe a weak supervision framework that extracts imperfect, yet highly granular, regional abnormality labels from free-text radiology reports. Our framework automatically labels each region in a custom ontology of anatomical regions, providing a structured profile of the pathologies in each imaging exam. Using these generated labels, we then train an attention-based, multi-task CNN architecture to detect and estimate the location of abnormalities in whole-body scans. We demonstrate empirically that our multi-task representation is critical for strong performance on rare abnormalities with limited training data. The representation also contributes to more accurate mortality prediction from imaging data, suggesting the potential utility of our framework beyond abnormality detection and location estimation.

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