Significant dose reduction is feasible in FDG PET/CT protocols without compromising diagnostic quality

Prieto, Elena; García-Velloso, María José; Rodríguez‐Fraile, Macarena; Morán, Verónica; García-García, Berta; Guillén, F; Morales, María; Sancho, Lidia; Peñuelas, Iván; Richter, José A.; Martí-Climent, Josep M.

doi:10.1016/j.ejmp.2018.01.021

Cited by 37 publications

(36 citation statements)

References 23 publications

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“…4b). This finding agrees with the clinical results reported in the recent paper of Prieto [16]. The author observed a statistically significant difference in both the image noise and the overall image quality indexes of PET images obtained after 18FDG activity administration of 5.2 and 3.7 MBq/kg on the Siemens mCT TOF-PET/CT scanner.…”

Section: Discussionsupporting

confidence: 91%

The role of activity, scan duration and patient's weight in the optimization of 18FDG imaging protocols on a TOF-PET/CT scanner

Matheoud

Al-Maymani

Oldani

et al. 2020

Preprint

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Background : Time-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality , in low counts acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on 18 F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment.Methods : The NEMA-IEC body phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR), and weight. The phantom was filled with 5.3 kBq/mL of FDG solution and the spheres with TBR of 21, 9, and 5 in 3 different sessions. Images were acquired at varying activity concentration from 5.1 to 1.3 kBq/mL and images were reconstructed for ESD of 30-151 seconds per bed position with and without Point Spread Function (PSF) correction. The parameters were all considered in simultaneous experiments and in a single analysis using multiple linear regression methods.Results : As expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and weight of the patient, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the weight of the patient and TBR of the lesion.Conclusions : Due to the interchangeable role of AC and ESD in modulating CRC, ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.

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Section: Discussionsupporting

confidence: 91%

The role of activity, scan duration and patient's weight in the optimization of 18FDG imaging protocols on a TOF-PET/CT scanner

Matheoud

Al-Maymani

Oldani

et al. 2020

Preprint

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“…In paediatric patients, the use of weight-based acquisition protocols justifies the variability of parameters, together with protocol intents. Four articles suggested a weight-based method to optimise the CT protocol [23,24,30,31], two papers proposed a method based on the variation of the tube current [26,34] and three studies compared different protocol acquisition techniques [15,19,32]. Indeed, Tonkopi et al [17] presented the comparison between two CT protocols in terms of noise index (from 25 to 27.1), pitch (from 1.75 to 1.35), rotation time (from 0.8 s to 0.5 s) and beam collimation (from 16 × 0.625 to 16 × 1.25).…”

Section: Discussionmentioning

confidence: 99%

CT protocol optimisation in PET/CT: a systematic review

et al. 2020

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Purpose: Currently, no consistent guidelines for CT scans used within PET/CT examinations are available. This systematic review provides an up-to-date overview of studies to answer the following questions: What are the specific CT protocols used in PET/CT? What are the possible purposes of requiring a CT study within a PET/CT scan? Is the CT protocol obtained from a dosimetric optimisation study?Materials and method: PubMed/MEDLINE, Cochrane Library, Embase and Scopus were systematically searched for relevant studies in accordance with the PRISMA statement. The literature search was conducted from January 2007 until June 2019. Data derived from studies were standardized in order to reduce possible biases, and they were divided into clinically homogeneous subgroups (adult, child or phantom). Subsequently, we divided the CT protocol intents into 3 types (anatomic localization only, attenuation correction only and diagnostic purpose). A narrative approach was used to summarise datasets and to investigate their heterogeneity (due to medical prescription methodology) and their combination in multiseries CT protocols. When weighted computed tomography dose index (CTDI w ) was available, we calculated the volumetric computed tomography dose index (CTDI vol ) using the pitch value to make the results uniform. Eventually, the correlation between protocol intents and CTDI vol values was obtained using a Kruskal-Wallis one-way ANOVA statistical test. Result: Starting from a total of 1440 retrieved records, twenty-four studies were eligible for inclusion in addition to two large multicentric works that we used to compare the results. We analyzed 87 CT protocols. There was a considerable range of variation in the acquisition parameters: tube current-time product revealed to have the most variable range, which was 10-300 mAs for adults and 10-80 mAs for paediatric patients. Seventy percent of datasets presented scans acquired with tube current modulation, 9% used fixed tube current and in 21% of them, this information was not available. Dependence between mean CTDI vol values and protocol intent was statistically significant (p = 0.002). As expected, in diagnostic protocols, there was a statistically significant difference between CTDI vol values of with and without contrast acquisitions (11.68 mGy vs 7.99 mGy, p = 0.009). In 13 out of 87 studies, the optimisation aim was not reported; in 2 papers, a clinical protocol was used; and in 11 works, a dose optimisation protocol was applied. (Continued on next page)Conclusions: According to this review, the dose optimisation in PET/CT exams depends heavily on the correct implementation of the CT protocol. In addition to this, considering the latest technology advances (i.e. iterative algorithms development), we suggest a periodic quality control audit to stay updated on new clinical utility modalities and to achieve a shared standardisation of clinical protocols. In conclusion, this study pointed out the necessity to better identify the specific CT protocol use within PET/CT scans, ...

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“…Prieto et al showed that average 18F-FDG dose reduction of 23.4% (down to 3.57 MBq/kg) is feasible without signi cant impairment of image quality. Yet, the study was performed on a 4-ring lutetium oxyorthosilicate PET/CT scanner [19]. On the other hand, Murray et al reported that emission scans as short as 15 sec per bed position su ciently identi ed tumour lesions for quanti cation.…”

Section: Discussionmentioning

confidence: 99%

Determining the Optimal Dose of 18F-FDG for Hodgkin lymphoma Imaging on PET/CT Camera with BGO Crystals

Dziuk

Witkowska-Patena

Giżewska

et al. 2020

Preprint

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Purpose: We aimed to find the minimum feasible dose of fluorodeoxyglucose (18F-FDG) in positron emission tomography/computed tomography (PET/CT) of Hodgkin lymphoma patients performed on a camera with bismuth germanate (BGO) crystals.Methods: Ninety-one 18F-FDG PET/CT scans with decreasing time per bed position (2 min, 1.5 min, 1 min, 50 sec, 40 sec, 30 sec and 20 sec) were assessed to evaluate image quality. Mean administered dose was 3.0±0.1 MBq/kg and mean uptake time was 54.0±8.7 min. The series quality was subjectively marked in 1-10 scale and then ranked 1-7 based on the mean mark. Interobserver rank correlation and intraclass correlation within each series were calculated. Phantom studies were also performed to determine if reduced acquisition time can be directly translated into a reduced dose. Results: We show the longer the time of acquisition the higher the mark and rank. The interobserver agreement in ranking was 100% with kappa coefficient of 1.00 (95% CI [0.83-1.0]). The general intraclass correlation coefficient was 0.945 (95% CI [0,936-0,952]). Only the series with 2 min and 1.5 min acquisition time were appropriate for assessment (mean mark ≥7). In phantom studies there was a linear correlation between time per bed, administered activity and number of total prompts detected by a scanner. Hence, reduction of acquisition time of 25% (from 2 min to 1.5 min) could be directly translated into a 25% dose reduction (from 3.0 to 2.25 MBq/kg).Conclusions: In patients with HL, 18F-FDG dose can be reduced by up to 25% when using a BGO crystal camera, without substantial impact on image quality.

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Significant dose reduction is feasible in FDG PET/CT protocols without compromising diagnostic quality

Cited by 37 publications

References 23 publications

The role of activity, scan duration and patient's weight in the optimization of 18FDG imaging protocols on a TOF-PET/CT scanner

The role of activity, scan duration and patient's weight in the optimization of 18FDG imaging protocols on a TOF-PET/CT scanner

CT protocol optimisation in PET/CT: a systematic review

Determining the Optimal Dose of 18F-FDG for Hodgkin lymphoma Imaging on PET/CT Camera with BGO Crystals

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