68Ga-DOTATATE PET/CT: The Optimum Standardized Uptake Value (SUV) Internal Reference

Ragab, Ahmed; Wu, Jianrong; Ding, Xue; Clark, Aurela; Mischen, Blaine T.; Chauhan, Aman; Oates, M. Elizabeth; Anthony, Lowell; Khouli, Riham El

doi:10.1016/j.acra.2020.08.028

Cited by 7 publications

(9 citation statements)

References 27 publications

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“…The liver SUV peak has the least variability within and between subjects, which supports using normal liver activity as a threshold for appropriate patient selection for PRRT and for normalization to derive tumor-to-organ ratios [12]. In the situation where there is a subtotal replacement of hepatic tissue by metastatic disease, the spleen is an alternative, albeit with greater variability [12]. 68 Ga-DOTATOC distributions in liver, spleen and kidneys, and also pituitary, thyroid and adrenals, remain unchanged after 4–6 cycles of PRRT, therefore tumor to nontumor tissue ratios are robust for therapeutic monitoring on serial 68 Ga PET scan [13].…”

Section: Discussionmentioning

confidence: 97%

“…The spleen, then kidneys, then liver are the organs shown to have the highest 68 Ga-DOTATATE activity at 1, 2 and 3 h after injection, the spleen being the major organ with the highest absorbed dose [11]. The liver SUV peak has the least variability within and between subjects, which supports using normal liver activity as a threshold for appropriate patient selection for PRRT and for normalization to derive tumor-to-organ ratios [12]. In the situation where there is a subtotal replacement of hepatic tissue by metastatic disease, the spleen is an alternative, albeit with greater variability [12].…”

Section: Discussionmentioning

confidence: 99%

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Differences in tumor-to-normal organ SUV ratios measured with 68Ga-DOTATATE PET compared with 177Lu-DOTATATE SPECT in patients with neuroendocrine tumors

Wong

Frey

Niedbala

et al. 2022

Nuclear Medicine Communications

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Background Our goal is to quantitatively compare radiotracer biodistributions within tumors and major normal organs on pretherapy 68 Ga-DOTATATE PET to post-therapy 177 Lu-DOTATATE single-photon emission computed tomography (SPECT) in patients receiving peptide receptor radionuclide therapy (PRRT).Methods PET/CT at ~ 60 min postinjection of Ga-68 DOTATATE and research 177 Lu-SPECT/CT imaging ~ at 4 h (SPECT1) and ~ 24 h (SPECT2) post-cycle#1 were available. Manual contours of lesions on baseline CT or MRI were applied to co-registered SPECT/CT and PET/CT followed by deep learning-based CT auto-segmentation of organs. Tumor-to-normal organ ratios (TNR) were calculated from standardized uptake values (SUV) mean and SUV peak for tumor, and SUV mean for non-tumoral liver (nliver), spleen and kidney.Results There were 90 lesons in 24 patients with progressive metastatic neuroendocrine tumor. The correlation between PET and SPECT SUV TNRs were poor/moderate: PET versus SPECT1 R 2 = 0.19, 0.21, 0.29; PET versus SPECT2 R 2 = 0.06, 0.16, 0.33 for TNR nliver ,TNR spleen ,TNR kidney , respectively. Across all patients, the average value of the TNR measured on PET was significantly lower than on SPECT at both time points (P < 0.001). Using SUV mean for tumor, average TNR values and 95% confidence intervals (CI) were PET: TNR nliver = 3.5 [CI: 3.0-3.9], TNR spleen = 1.3 [CI, 1.2-1.5], TNR kidney = 1.7 [CI: 1.6-1.9]; SPECT1: TNR nliver = 10 [CI: 8.2-11.7], TNR spleen = 2.9 [CI: 2.5-3.4], TNR kidney = 2.8 [CI: 2.3-3.3]; SPECT2: TNR nliver = 16.9 [CI: 14-19.9], TNR spleen = 3.6 [CI: 3-4.2], TNR kidney = 3.6 [CI: 3.0-4.2]. Comparison of PET and SPECT results in a sphere phantom study demonstrated that these differences are not attributed to imaging modality.Conclusions Differences in TNR exist for the theranostic pair, with significantly higher SUV TNR on 177 Lu SPECT compared with 68 Ga PET. We postulate this phenomenon is due to temporal differences in DOTATATE uptake and internalization in tumor as compared to normal organs.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Differences in tumor-to-normal organ SUV ratios measured with 68Ga-DOTATATE PET compared with 177Lu-DOTATATE SPECT in patients with neuroendocrine tumors

Wong

Frey

Niedbala

et al. 2022

Nuclear Medicine Communications

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“…In this regard, previous studies have shown that higher SUVs can be measured in patients with a higher BMI. 26,27 In this work, the SNR due to the OSEM reconstruction algorithm was evaluated as a function of the patients' weights. The findings have shown a reduced nonlinear fitting.…”

Section: Discussionmentioning

confidence: 99%

Impact of Region-of-Interest Delineation on Stability and Reproducibility of Liver SNR Measurements in 68Ga-PSMA PET/CT

et al. 2023

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Objective This study aims to assess the impact of various regions of interest (ROIs) and volumes of interest (VOIs) delineations on the reproducibility of liver signal-to-noise-ratio (SNRliver) measurements, as well as to find the most reproducible way to estimate it in gallium-68 positron emission tomography (68Ga-PET) imaging. We also investigated the SNRliver-weight relationship for these ROIs and VOIs delineations. Methods A cohort of 40 patients (40 males; mean weight: 76.5 kg [58–115 kg]) with prostate cancer were included. 68Ga-PET/CT imaging (mean injected activity: 91.4 MBq [51.2 MBq to 134.1 MBq] was performed on a 5-ring bismuth germanium oxide-based Discovery IQ PET/CT using ordered subset expectation maximization image reconstruction algorithm. Afterward, circular ROIs and spherical VOIs with two different diameters of 30 and 40 mm were drawn on the right lobe of the livers. The performance of the various defined regions was evaluated by the average standardized uptake value (SUVmean), standard deviation (SD) of the SUV (SUVSD), SNRliver, and SD of the SNRliver metrics. Results There were no significant differences in SUVmean among the various ROIs and VOIs (p > 0.05). On the other hand, the lower SUVSD was obtained by spherical VOI with diameter of 30 mm. The largest SNRliver was obtained by ROI (30 mm). The SD of SNRliver with ROI (30 mm) was also the largest, while the lowest SD of SNRliver was observed for VOI (40 mm). There is a higher correlation coefficient between the patient-dependent parameter of weight and the image quality parameter of SNRliver for both VOI (30 mm) and VOI (40 mm) compared to the ROIs. Conclusion Our results indicate that SNRliver measurements are affected by the size and shape of the respective ROIs and VOIs. The spherical VOI with a 40 mm diameter leads to more stable and reproducible SNR measurement in the liver.

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“…The standardized uptake value (SUV) is a semiquantitative measurement prone to variation based on isotope preparation and time to delivery, among other factors, such that it has only limited utility in comparing tumor biological differences among patients and treatment response assessment. 64 As such, a higher SUV on one scan compared with prior imaging does not denote progression in and of itself. Finally, when considering treatment with PRRT for patients with the risk factors for serious hematologic toxicity outlined previously, clinicians should discuss the risk of treatment-related myelodysplastic neoplasia with their patients, and should have a low threshold for investigating persistent cytopenia or macrocytosis.…”

Section: Patient and Clinician Communicationmentioning

confidence: 99%

“…Integration of Palliative Care Into Standard Oncology Care 78 (http://ascopubs.org/doi/10.1200/JCO.2016.70.1474)Patient-Clinician Communication 64 (http://ascopubs.org/doi/10.1200/JCO.2017.75.2311)…”

Section: Additional Resourcesmentioning

confidence: 99%

Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline

Del Rivero,

Perez,

Kennedy

et al. 2023

JCO

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PURPOSE To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs). METHODS ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice. RESULTS Eight randomized controlled trials met the inclusion criteria for the systematic review. RECOMMENDATIONS Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)–positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .

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68Ga-DOTATATE PET/CT: The Optimum Standardized Uptake Value (SUV) Internal Reference

Cited by 7 publications

References 27 publications

Differences in tumor-to-normal organ SUV ratios measured with 68Ga-DOTATATE PET compared with 177Lu-DOTATATE SPECT in patients with neuroendocrine tumors

Differences in tumor-to-normal organ SUV ratios measured with 68Ga-DOTATATE PET compared with 177Lu-DOTATATE SPECT in patients with neuroendocrine tumors

Impact of Region-of-Interest Delineation on Stability and Reproducibility of Liver SNR Measurements in 68Ga-PSMA PET/CT

Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline

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