Radiation Dosimetry of <sup>99m</sup>Tc-PSMA I&amp;S: A Single-Center Prospective Study

Urbán, Szabolcs; Meyer, Catherine; Dahlbom, Magnus; Farkas, I.; Sipka, Gábor; Besenyi, Zsuzsanna; Czernin, Johannes; Calais, Jérémie; Pajor, László

doi:10.2967/jnumed.120.253476

Cited by 20 publications

(22 citation statements)

References 13 publications

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“…A summary of dosimetric parameters for various organs is given in Table S2, and the mean effective dose equivalent of the whole body was 1.26×10 − 3 mSv/MBq, which is consistent with those for other molecules labelled with 99m Tc [12,13].…”

Section: Dynamic Biodistribution In Organs and Dosimetry Estimationsupporting

confidence: 78%

The role of 99mTc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience

Jia

et al. 2022

Preprint

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Background Recently, PET/ CT imaging with radiolabelled FAP inhibitors (FAPIs) has been widely evaluated in diverse diseases. However, rare report has been published using SPECT/CT, a more available imaging method, with 99mTc-labelled FAPI. In this study, we evaluated the potential effect of 99mTc-HFAPi in clinical analysis for digestive system tumours. Methods This is a single-centre prospective diagnostic efficiency study (Ethic approved No.: XJTU1AF2021LSK-021 of First Affiliated Hospital of Xi’an Jiaotong University and ChiCTR2100048093 of Chinese Clinical Trial Register). 40 patients with suspected or confirmed digestive system tumours underwent 99mTc-HFAPi SPECT/CT between January through June 2021. For dynamic biodistribution and dosimetry estimation, whole-body planar scintigraphy was performed at 10, 30, 90, 150, and 240 min post-injection. Optimal acquisition time was considered at 60–90 min post-injection and semi-quantified using SUVmax and T/B ratio. The diagnostic performance of 99mTc-HFAPi were calculated and compared with those of contrast-enhanced CT (ceCT) using McNemar test, and the changes of tumour stage and oncologic management were recorded. Results Physiological distribution of 99mTc-HFAPi was observed in the liver, pancreas, gallbladder, and to a lesser extent in the kidneys, spleen and thyroid. The diagnostic sensitivity of 99mTc-HFAPi for non-operative primary lesions was similar to that of ceCT (94.29% [33/35] vs 100% [35/35], respectively; P = 0.5); in local relapse detection, 99mTc-HFAPi was successfully detected in 100% (n = 3) of patients. In the diagnosis of suspected metastatic lesions, 99mTc-HFAPi exhibited higher sensitivity (89.66% [26/29] vs 68.97% [20/29], respectively, P = 0.03) and specificity (97.9% [47/48] vs 85.4% [41/48], respectively, P = 0.03) than ceCT, especially with 100% (24/24) specificity in the diagnosis of liver metastases, resulting in 20.0% (8/40) changes in TNM stage and 15.0% (6/40) changes in oncologic management. Conclusion 99mTc-HFAPi demonstrates a greater diagnostic efficiency than ceCT in the detection of distant metastasis, especially in identifying liver metastases.

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Section: Dynamic Biodistribution In Organs and Dosimetry Estimationsupporting

confidence: 78%

The role of 99mTc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience

Jia

et al. 2022

Preprint

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“…This review also underscores that fluorescent agents based on PSMA inhibitors or antibodies are commonly used at concentrations that reach therapeutic levels ([ 15 , 16 ]; 2.5 mg/kg in patients). These high doses also tend to go hand in hand with, i.e., high kidney retention and renal excretion, and may even exert unwanted pharmacological activity [ 6 , 15 , 17 ]. When realizing that the ureter is standardly dissected during RARP, spillage of fluorescence-containing urine into the surgical field can cause false positive findings [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of fluorescence imaging at microdosing using a hybrid PSMA tracer during robot-assisted radical prostatectomy in a large animal model

et al. 2022

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Background With the rise of prostate-specific membrane antigen (PSMA) radioguided surgery, which is performed using a microdosing regime, demand for visual target confirmation via fluorescence guidance is growing. While proven very effective for radiotracers, microdosing approaches the detection limit for fluorescence imaging. Thus, utility will be highly dependent on the tracer performance, the sensitivity of the fluorescence camera used, and the degree of background signal. Using a porcine model the ability to perform robot-assisted radical prostatectomy under fluorescence guidance using the bimodal or rather hybrid PSMA tracer (99mTc-EuK-(SO3)Cy5-mas3) was studied, while employing the tracer in a microdosing regime. This was followed by ex vivo evaluation in surgical specimens obtained from prostate cancer patients. Results T50% blood and T50% urine were reached at 85 min and 390 min, in, respectively, blood and urine. Surgical fluorescence imaging allowed visualization of the prostate gland based on the basal PSMA-expression in porcine prostate. Together, in vivo visualization of the prostate and urinary excretion suggests at least an interval of > 7 h between tracer administration and surgery. Confocal microscopy of excised tissues confirmed tracer uptake in kidney and prostate, which was confirmed with PSMA IHC. No fluorescence was detected in other excised tissues. Tumor identification based on ex vivo fluorescence imaging of human prostate cancer specimens correlated with PSMA IHC. Conclusion Intraoperative PSMA-mediated fluorescence imaging with a microdosing approach was shown to be feasible. Furthermore, EuK‐(SO3)Cy5‐mas3 allowed tumor identification in human prostate samples, underlining the translational potential of this novel tracer. Trial registration Approval for use of biological material for research purposes was provided by the Translational Research Board of the Netherlands Cancer Institute-Antoni van Leeuwenhoek hospital (NKI-AvL) under reference IRBm19-273 (22/10/2019).

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“…In a study including 210 PCa patients, high detection rates were found for [ 99m Tc]Tc-PSMA I&S for PSA levels > 4 ng/mL [ 114 ]. The radiation dosimetry of [ 99m Tc]Tc-PSMA I&S, which was performed in a single-center study, resulted in comparable effective doses with other 99m Tc radiopharmaceuticals and lower effective doses than either 68 Ga- or 18 F-radiolabeled PSMA inhibitors ([ 99m Tc]Tc-PSMA I&S: 0.0052 mSv/MBq, [ 68 Ga]Ga-PSMA-11: 0.0236 mSv/MBq, [ 18 F]PSMA-1007: 0.022 mSv/MBq) [ 115 , 116 , 117 ].…”

Section: Psma Inhibitors For Guided Surgerymentioning

confidence: 99%

Radiolabeled PSMA Inhibitors

Neels

Kopka

Liolios

et al. 2021

Cancers

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PSMA has shown to be a promising target for diagnosis and therapy (theranostics) of prostate cancer. We have reviewed developments in the field of radio- and fluorescence-guided surgery and targeted photodynamic therapy as well as multitargeting PSMA inhibitors also addressing albumin, GRPr and integrin αvβ3. An overview of the regulatory status of PSMA-targeting radiopharmaceuticals in the USA and Europe is also provided. Technical and quality aspects of PSMA-targeting radiopharmaceuticals are described and new emerging radiolabeling strategies are discussed. Furthermore, insights are given into the production, application and potential of alternatives beyond the commonly used radionuclides for radiolabeling PSMA inhibitors. An additional refinement of radiopharmaceuticals is required in order to further improve dose-limiting factors, such as nephrotoxicity and salivary gland uptake during endoradiotherapy. The improvement of patient treatment achieved by the advantageous combination of radionuclide therapy with alternative therapies is also a special focus of this review.

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Radiation Dosimetry of ^99mTc-PSMA I&S: A Single-Center Prospective Study

Cited by 20 publications

References 13 publications

The role of 99mTc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience

The role of 99mTc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience

Feasibility of fluorescence imaging at microdosing using a hybrid PSMA tracer during robot-assisted radical prostatectomy in a large animal model

Radiolabeled PSMA Inhibitors

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Radiation Dosimetry of 99mTc-PSMA I&S: A Single-Center Prospective Study

Cited by 20 publications

References 13 publications

The role of 99mTc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience

The role of 99mTc-HFAPi SPECT/CT in patients with malignancies of digestive system: first clinical experience

Feasibility of fluorescence imaging at microdosing using a hybrid PSMA tracer during robot-assisted radical prostatectomy in a large animal model

Radiolabeled PSMA Inhibitors

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Radiation Dosimetry of ^99mTc-PSMA I&S: A Single-Center Prospective Study