Impact of PET reconstruction protocols on quantification of lesions that fulfil the PERCIST lesion inclusion criteria

Devriese, Joke; Beels, Laurence; Maes, Alex; Wiele, Christophe Van de; Pottel, Hans

doi:10.1186/s40658-018-0235-6

Cited by 26 publications

(24 citation statements)

References 32 publications

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“…A noisy RC curve also indicates that the injected activity indeed is at the lower limit. We need to take into account that treatment response assessment can be done only if the reconstruction protocol meets the EARL requirements [22].…”

Section: Discussionmentioning

confidence: 99%

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Optimization of injected 68Ga-PSMA activity based on list-mode phantom data and clinical validation

et al. 2020

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Optimization of injected gallium-68 ( 68 Ga) activity for 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography ( 68 Ga-PSMA PET/CT) studies is relevant for image quality, radiation protection, and from an economic point of view. However, no clear guidelines are available for 68 Ga-PSMA studies. Therefore, a phantom study is performed to determine the highest coefficient of variation (COV) acceptable for reliable image interpretation and quantification. To evaluate image interpretation, the relationship of COV and contrast-to-noise ratio (CNR) was studied. The CNR should remain larger than five, according to the Rose criterion. To evaluate image quantification, the effect of COV on the percentage difference (PD) between quantification results of two studies was analyzed. Comparison was done by calculating the PD of the SUV max . The maximum allowable PD SUVmax was set at 20%. The highest COV at which both criteria are still met is defined as COV max . Of the NEMA Image Quality phantom, a 20 min/bed (2 bed positions) scan was acquired in list-mode PET (Philips Gemini TF PET/CT). The spheres to background activity ratio was approximately 9:1. To obtain images with different COV, lower activity was mimicked by reconstructions with acquisition times of 10 min/bed to 5 s/bed. Pairs of images were obtained by reconstruction of two non-overlapping parts of list-mode data. For the 10-mm diameter sphere, a COV of 25% still meets the criteria of CNR SUVmean ≥ 5 and PD SUVmax ≤ 20%. This phantom scan was acquired with an acquisition time of 116 s and a background activity concentration of 0.71 MBq/kg. Translation to a clinical protocol results in a clinical activity regimen of 3.5 MBq/kg min at injection. To verify this activity regimen, 15 patients (6 MBq/kg min) with a total of 22 lesions are included. Additional reconstructions were made to mimic the proposed activity regimen. Based on the CNR SUVmax , no lesions were missed with this proposed activity regimen. For our institution, a clinical activity regimen of 3.5 MBq/kg min at injection is acceptable, which indicates that activity can be reduced by almost 50% compared with the current code of practice. Our proposed method could be used to obtain an objective activity regimen for other PET/CT systems and tracers.

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Section: Discussionmentioning

confidence: 99%

“…A dataset of the NEMA NU2-2001 Image Quality phantom (IQ phantom) was created. The six spheres (10,13,17,22,28, and 37 mm diameter) of the IQ phantom were filled with a known concentration 68 Ga. The NEMA lung insert was situated at the center of the phantom.…”

Section: Phantom Studymentioning

confidence: 99%

Optimization of injected 68Ga-PSMA activity based on list-mode phantom data and clinical validation

et al. 2020

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“…Previous reports argued that PSF reconstructions should be used for qualitative purposes (i.e. lesion detection) and that non-PSF images (such as EARL1) should be used for tumour quantification [18, 33]. However, Quak et al found that with additional image filtering the higher lesion detection and image resolution of PSF images do not need to be impaired in order to meet the EARL criteria [34].…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of 18F-fluorodihydrotestosterone PET-CT to count statistics and reconstruction protocol in metastatic castration-resistant prostate cancer

et al. 2019

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Objectives Whole body [ 18 F]-fluorodihydrotestosterone positron emission tomography ([ 18 F]FDHT PET) imaging directly targets the androgen receptor and is a promising prognostic and predictive biomarker in metastatic castration-resistant cancer (mCRPC). To optimize [ 18 F]FDHT PET-CT for diagnostic and response assessment purposes, we assessed how count statistics and reconstruction protocol affect its accuracy, repeatability, and lesion detectability. Methods Whole body [ 18 F]FDHT PET-CT scans were acquired on an analogue PET-CT on two consecutive days in 14 mCRPC patients harbouring a total of 336 FDHT-avid lesions. Images were acquired at 45 min post-injection of 200 MBq [ 18 F]FDHT at 3 min per bed position. List-mode PET data were split on a count-wise basis, yielding two statistically independent scans with each 50% of counts. Images were reconstructed according to current EANM Research Ltd. (EARL1, 4 mm voxel) and novel EARL2 guidelines (4 mm voxel + PSF). Per lesion, we measured SUVpeak, SUVmax, SUVmean, and contrast-to-noise ratio (CNR). SUV was normalized to dose per bodyweight as well as to the parent plasma input curve integral. Variability was assessed with repeatability coefficients (RCs). Results Count reduction increased liver coefficient of variation from 9.0 to 12.5% and from 10.8 to 13.2% for EARL1 and EARL2, respectively. SUVs of EARL2 images were 12.0–21.7% higher than EARL1. SUVs of 100% and 50% count data were highly correlated ( R 2 > 0.98; slope = 0.97–1.01; ICC = 0.99–1.00). Intrascan variability was volume-dependent, and count reduction resulted in higher intrascan variability for EARL2 than EARL1 images. Intrascan RCs were lowest for SUVmean (8.5–10.6%), intermediate for SUVpeak (12.0–16.0%), and highest for SUVmax (17.8–22.2%). Count reduction increased test-retest variance non-significantly ( p > 0.05) for all SUV types and normalizations. For SUVpeak at 50% of counts, RCs remained < 30% when small lesions were excluded. Splitting data reduced CNR by median 4.6% (interquartile range 1.2–8.7%) and 4.6% (interquartile range 1.2–8.7%) for EARL1 and EARL2 images, respectively. Conclusions Reducing [ 18 F]FDHT PET acquisition time from 3 min to 1.5 per bed position resulted in a repeatability of SUVpeak (bodyweight) remaining ≤ 30%, which is generally acceptable for response monitoring purposes. However, EARL2 reconstruction was more affected, especially for SUVmax whose repeatability tended to exceed 30%. Lesion detectability was only slightly impaired by reducing acquisition time, which might not be clinically relevant in mCRPC. Electronic supplementary material The online version of this article (10.1186/s13550-019-0531-8) co...

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“…While a detailed description of the EARL protocol is beyond the scope of this text, it has been shown that compliance with EARL is feasible and able to resolve most causes of errors in quantitative PET measurements when combined with adherence to the FDG-PET/CT imaging guidelines (41). Designed in 2010, the EARL currently do not cover newer systems, that have been shown to produce higher maximum SUV values (Figure 2) resulting in discordant treatment response assessments (42). Based on these findings, an update of the EARL system has recently been proposed to include modern PET/CT equipment to mitigate these discrepancies (43).…”

Section: Harmonizationmentioning

confidence: 99%

Quality Assessment in FDG-PET/CT Imaging of Head-and-Neck Cancer: One Home Run Is Better Than Two Doubles

2020

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2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) is indicated in head-and-neck cancer for the initial workup when clinically indicated (e. g., large tumors, clinically positive neck, cervical adenopathy from an unknown primary, etc.), for the assessment of treatment response 12 weeks after completion of (chemo)radiotherapy, and during follow-up when there is suspicion of relapse. The successful implementation of FDG-PET/CT in routine clinical practice requires an in-depth understanding of the recent advances in physics and engineering that have significantly improved the imaging capabilities of PET/CT scanners (e.g., digital silicon photomultipliers, point-spread function modeling, and time-of-flight, and Bayesian penalized likelihood reconstruction). Moreover, a coordinated harmonization effort from professional societies (e.g., EANM) and international bodies (e.g., IAEA) has resulted in the creation of quality assurance frameworks (e.g., QUANUM, EARL, GMP) and guidelines that collectively cover the entire spectrum from tracer production, hardware calibration, patient preparation, and scan acquisition, to image interpretation (e.g., PERCIST, Hopkins criteria). The ultimate goal is to standardize the PET/CT technique and to guarantee accurate and reproducible imaging results for every patient. This review summarizes the recent technical breakthroughs in PET/CT scan design and describes the existing quality assessment frameworks with a focus on applications in head-and-neck cancer. Strict adherence to these harmonization efforts will enable leveraging the full potential of PET/CT and translate the proven benefits of this technique into tangible improvements in outcome for patients with head-and-neck cancer in routine clinical care.

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Impact of PET reconstruction protocols on quantification of lesions that fulfil the PERCIST lesion inclusion criteria

Cited by 26 publications

References 32 publications

Optimization of injected 68Ga-PSMA activity based on list-mode phantom data and clinical validation

Optimization of injected 68Ga-PSMA activity based on list-mode phantom data and clinical validation

Sensitivity of 18F-fluorodihydrotestosterone PET-CT to count statistics and reconstruction protocol in metastatic castration-resistant prostate cancer

Quality Assessment in FDG-PET/CT Imaging of Head-and-Neck Cancer: One Home Run Is Better Than Two Doubles

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