Benefits of Point-Spread Function and Time of Flight for PET/CT Image Quality in Relation to the Body Mass Index and Injected Dose

Akamatsu, Go; Mitsumoto, Katsuhiko; Ishikawa, Kaori; Taniguchi, Takafumi; Ohya, Nobuyoshi; Baba, Shingo; Abe, Koichiro; Sasaki, Masayuki

doi:10.1097/rlu.0b013e31828da3bd

Cited by 23 publications

(12 citation statements)

References 26 publications

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“…Finally, it is noteworthy that this study and others evaluating the impact of PSF reconstruction or a combination of PSF reconstruction and time-of-flight on quantitative values in oncology [7, 8, 24, 25] have been performed at a time when many efforts are being made to harmonize SUV values in multicentre trials [26–28]. The use of different generation PET systems in which FDG PET is used for therapy monitoring in breast cancer patients could lead to inaccurate response evaluation.…”

Section: Discussionmentioning

confidence: 90%

Staging the axilla in breast cancer patients with 18F-FDG PET: how small are the metastases that we can detect with new generation clinical PET systems?

Bellèvre

Fournier

Switsers

et al. 2014

Eur J Nucl Med Mol Imaging

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PurposePoint spread function (PSF) reconstruction improves spatial resolution throughout the entire field of view of a PET system and can detect smaller metastatic deposits than conventional algorithms such as OSEM. We assessed the impact of PSF reconstruction on quantitative values and diagnostic accuracy for axillary staging of breast cancer patients, compared with an OSEM reconstruction, with emphasis on the size of nodal metastases.MethodsThis was a prospective study in a single referral centre in which 50 patients underwent an 18F-FDG PET examination before axillary lymph node dissection. PET data were reconstructed with an OSEM algorithm and PSF reconstruction, analysed blindly and validated by a pathologist who measured the largest nodal metastasis per axilla. This size was used to evaluate PET diagnostic performance.ResultsOn pathology, 34 patients (68 %) had nodal involvement. Overall, the median size of the largest nodal metastasis per axilla was 7 mm (range 0.5 – 40 mm). PSF reconstruction detected more involved nodes than OSEM reconstruction (p = 0.003). The mean PSF to OSEM SUVmax ratio was 1.66 (95 % CI 1.01 – 2.32). The sensitivities of PSF and OSEM reconstructions were, respectively, 96 % and 92 % in patients with a largest nodal metastasis of >7 mm, 60 % and 40 % in patients with a largest nodal metastasis of ≤7 mm, and 92 % and 69 % in patients with a primary tumour ≤30 mm. Biggerstaff graphical comparison showed that globally PSF reconstruction was superior to OSEM reconstruction. The median sizes of the largest nodal metastasis in patients with nodal involvement not detected by either PSF or OSEM reconstruction, detected by PSF but not by OSEM reconstruction and detected by both reconstructions were 3, 6 and 16 mm (p = 0.0064) respectively. In patients with nodal involvement detected by PSF reconstruction but not by OSEM reconstruction, the smallest detectable metastasis was 1.8 mm.ConclusionAs a result of better activity recovery, PET with PSF reconstruction performed better than PET with OSEM reconstruction in detecting nodal metastases ≤7 mm. However, its sensitivity is still insufficient for it to replace surgical approaches for axillary staging. PET with PSF reconstruction could be used to perform sentinel node biopsy more safely in patients with a primary tumour ≤30 mm and with unremarkable PET results in the axilla.Electronic supplementary materialThe online version of this article (doi:10.1007/s00259-014-2689-7) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 90%

Staging the axilla in breast cancer patients with 18F-FDG PET: how small are the metastases that we can detect with new generation clinical PET systems?

Bellèvre

Fournier

Switsers

et al. 2014

Eur J Nucl Med Mol Imaging

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“…The suggested cutoff value represents a valid suggestion for daily practice; however, several factors impacting on PET IQ have to be considered ( 1 , 9 , 15 , 16 ). Scanner performance may for instances be enhanced by improved system geometry and novel non-photomultiplier based detectors ( 17 ) and time-of-flight imaging ( 7 , 18 ). Different reconstruction parameters exist and IQ may further be improved by applying modifications to raw data or changing properties in the image domain ( 19 ).…”

Section: Discussionmentioning

confidence: 99%

“…Many studies have not only explored into different acquisition parameters ( 5 – 8 ) but also compared the IQ of a wide range of FDG dosages ( 9 , 10 ). All of the aforementioned studies are, however, biased by the inter-individual variability among different patient cohorts.…”

Section: Introductionmentioning

confidence: 99%

Intra-individual comparison of PET/CT with different body weight-adapted FDG dosage regimens

Geismar

Stolzmann

Sah

et al. 2015

Acta Radiologica Open

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Background18F-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/ computed tomography (CT) imaging demands guidelines to safeguard sufficient image quality at low radiation exposure. Various FDG dose regimes have been investigated; however, body weight-adapted dose regimens and related image quality (IQ) have not yet been compared in the same patient.PurposeTo investigate the relationship between FDG dosage and image quality in PET/CT in the same patient and determine prerequisites for low dosage scanning.Material and MethodsThis study included 61 patients undergoing a clinically indicated PET/CT imaging study and follow-up with a normal (NDS, 5 MBq/kg body weight [BW]) and low dosage scanning protocol (LDS, 4 MBq/kg BW), respectively, using a Discovery VCT64 scanner. Two blinded and independent readers randomly assessed IQ of PET using a 5-point Likert scale and signal-to-noise ratio (SNR) of the liver.ResultsBody mass index (BMI) was significantly lower at LDS (P = 0.021) and represented a significant predictor of SNR at both NDS (P < 0.001) and LDS (P = 0.005). NDS with a mean administered activity of 340 MBq resulted in significantly higher IQ (P < 0.001) and SNR as compared with LDS with a mean of 264 MBq (F-value = 23.5, P < 0.001, mixed model ANOVA adjusted for covariate BMI). Non-diagnostic IQ at LDS was associated with a BMI > 22 kg/m2.ConclusionFDG dosage significantly predicts IQ and SNR in PET/CT imaging as demonstrated in the same patient with optimal IQ achieved at 5 MBq/kg BM. PET/CT imaging at 4 MBq/kg BW may only be recommended in patients with a BMI ≤ 22 kg/m2 to maintain diagnostic IQ.

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“…To overcome degradation of analogic PET IQ in overweight and obese patients we can increase acquisition time and/or injected activity [8,13,15,16]. Also technical progress especially TF and optimization in reconstruction parameters [9,14,17] can contribute to obtain a more constant PET IQ. However little has been described about the necessity and modalities of these compensatory techniques in dPET/CT.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Patient’s Body Habitus on PET Image Quality in Digital and Analogic PET/CT

Weyts

Quak

Licaj

et al. 2020

Preprint

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Background: New digital versus analogic PET has higher temporal resolution and more stable count rate, potentially limiting the degradation of PET image quality in larger patients. We wanted to describe the influence of patient’s body habitus on [18F]FDG PET image quality primary in digital PET/CT and analogic PET/CT.Results:We studied retrospectively the relation between patient’s weight, BMI, fatty massand PET image quality, described by the coefficient of variance in the liver (CVliv) and visually.177 unique patient exams on digital PET/CT (weight 35-127 kg; BMI 15-44 kg/m2) were performed with 2 protocols (protocol 1: N=52: 3MBq (0,08mCi)/kg [18F]FDG; 2minutes/bed position; 2iterations10subsets; 2mm diameter voxels and protocol 2: N=125: 4MBq (0,11mCi) /kg [18F]FDG; 1min/bed position; 4iterations4subsets; 2mm voxels).74 unique patient exams were analyzed on analogic PET/CT (weight 38-130 kg; BMI 14-52 kg/m2; with one protocol: 4MBq (0,11mCi)/kg [18F]FDG; 2min40sec/bedposition for BMI<25 and 3min40sec for BMI ≥25; 3iterations21subsets; 4mm voxels).Uni-and multivariable linear regression analysis showed positive association of CVliv with weight, BMI, fatty mass (p£0.009) and male sex (p£0,03) for both camera’s, with good fit in CVliv versus weight model on digital PET/CT (R2 up to 0.62). 4MBq (0,11mCi) protocol on digital PET/CT versus analogic PET/CT obtained lower CVliv on digital PET/CT in patients <70kg, without a difference if 70-<90kg and in Pearson correlation coefficients (p=0,26) despite substantially longer acquisition time for analogic PET/CT. For digital PET/CT CVliv increased similarly with weight for both protocols, up to 26% [95% Confidence Interval 2-56%] for ³90 kg versus <70kg, but overall CVliv values were lower in 4MBq (0,11mCi) protocol 2.Also visually PET image quality decreased with habitus on each camera (p£0.001) and was lower in females on digital PET/CT only (p=0,04).Conclusions:[18F]FDG PET image quality decreases with weight and enlarging body habitus on digital and analogic PET/CT imposing further optimization and harmonization also in digital PET/CT. This is important for clinical routine, but also (multicentric) research and development of artificial intelligence software.

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Benefits of Point-Spread Function and Time of Flight for PET/CT Image Quality in Relation to the Body Mass Index and Injected Dose

Cited by 23 publications

References 26 publications

Staging the axilla in breast cancer patients with 18F-FDG PET: how small are the metastases that we can detect with new generation clinical PET systems?

Staging the axilla in breast cancer patients with 18F-FDG PET: how small are the metastases that we can detect with new generation clinical PET systems?

Intra-individual comparison of PET/CT with different body weight-adapted FDG dosage regimens

The Impact of Patient’s Body Habitus on PET Image Quality in Digital and Analogic PET/CT

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