BACKGROUND:One can assess cortical defects on the early images of [99mTc]Tc-MAG3 renography. We aimed to assess interobserver and intraobserver reproducibility for detecting renal cortical defects using [99mTc]Tc-MAG3 for adults and children; identify causes for poor inter- and intraobserver reproducibility and to assess the effect of the kidney to background ratio (KTBR) on reproducibility. METHODS:One hundred adult and 200 pediatric renograms were included. The observers reviewed the summed 1-minute posterior images for the first four minutes to detect cortical defects. Interobserver reproducibility between three observers and intra-observer reproducibility for two observers were determined. Agreement was tested using percentage agreement, Krippendorff's reliability coefficient alpha and Cohen's kappa statistic. The association between KTBR and agreement was evaluated. RESULTS:Interobserver agreement on the 1-2 minutes images was 78 (95% CI: 74.8-82.7%) and 79.7 (95% CI: 75.9-83.5%) for left and right kidneys respectively. Intraobserver percentage was 89.7% (95% CI: 86.2-93.1%) for the senior and 80.7% (95% CI: 76.2-85.2%) for the junior observer. In 13.5% (27) of the adult and 4.5% (19) of the pediatric kidneys the difference in image interpretation between the observers would have had a clinical impact. If the KTBR is ≤2, the percentage agreement was between 61.5% and 64.8%. In cases with a KTBR >2, the percentage agreement was between 83.6% and 87.1%. CONCLUSIONS:The percentage interobserver agreement was moderate. Disagreement between normal and abnormal cases were infrequent. The interobserver reproducibility was decreased when the KTBR was ≤2.

EDITORIAL article Front. Nucl. Med., 11 April 2024Sec. Radionuclide Therapy Volume 4 - 2024 | https://doi.org/10.3389/fnume.2024.1385097

Theranostics with radioligands (radiotheranostics) has played a pivotal role in oncology. Radiotheranostics explores the molecular targets expressed on tumor cells to target them for imaging and therapy. In this way, radiotheranostics entails non-invasive demonstration of the in vivo expression of a molecular target of interest through imaging followed by the administration of therapeutic radioligand targeting the tumor-expressed molecular target. Therefore, radiotheranostics ensures that only patients with a high likelihood of response are treated with a particular radiotheranostic agent, ensuring the delivery of personalized care to cancer patients. Within the last decades, a couple of radiotheranostics agents, including Lutetium-177 DOTATATE (177Lu-DOTATATE) and Lutetium-177 prostate-specific membrane antigen (177Lu-PSMA), were shown to prolong the survival of cancer patients compared to the current standard of care leading to the regulatory approval of these agents for routine use in oncology care. This recent string of successful approvals has broadened the interest in the development of different radiotheranostic agents and their investigation for clinical translation. In this work, we present an updated appraisal of the literature, reviewing the recent advances in the use of established radiotheranostic agents such as radioiodine for differentiated thyroid carcinoma and Iodine-131-labeled meta-iodobenzylguanidine therapy of tumors of the sympathoadrenal axis as well as the recently approved 177Lu-DOTATATE and 177Lu-PSMA for differentiated neuroendocrine tumors and advanced prostate cancer, respectively. We also discuss the radiotheranostic agents that have been comprehensively characterized in preclinical studies and have shown some clinical evidence supporting their safety and efficacy, especially those targeting fibroblast activation protein (FAP) and chemokine receptor 4 (CXCR4) and those still being investigated in preclinical studies such as those targeting poly (ADP-ribose) polymerase (PARP) and epidermal growth factor receptor 2.

Abstract Background PSMA PET/CT is the most sensitive molecular imaging modality for prostate cancer (PCa), yet much of the developing world has little or no access to PET/CT. [99mTc]Tc-PSMA scintigraphy (PS) is a cheaper and more accessible gamma camera-based alternative. However, many resource-constrained departments have only a single camera without tomographic or hybrid imaging functionality, and camera time is frequently in high demand. Simplifying imaging protocols by limiting the field of view (FOV) and omitting SPECT/CT or even SPECT may provide a partial solution. The aim was thus to determine the adequacy of PS planar-only and/or SPECT-only imaging protocols with a limited FOV. Methods The scans of 95 patients with histologically proven PCa who underwent PS with full-body planar and multi-FOV SPECT/CT were reviewed. The detection rates for uptake in the prostate gland/bed and in metastases were compared on planar, SPECT, and SPECT/CT. The agreement between modalities was calculated for the detection of metastases and for staging. The impact of imaging a limited FOV was determined. Results Pathological prostatic uptake was seen in all cases on SPECT/CT (excluding two post-prostatectomy patients), 90.3% of cases on SPECT, and 15.1% on planar images (p < 0.001). Eleven (11.7%) patients had seminal vesicle involvement on SPECT/CT, which was undetectable/indistinguishable on planar images and SPECT. The agreement between modalities was moderate to good (κ = 0.41 to 0.61) for the detection of nodal metastases, with detection rates that did not differ significantly (SPECT/CT = 11.6%, SPECT = 8.4%, planar = 5.3%). Detection rates for bone metastases were 14.7% (SPECT/CT) and 11.6% (SPECT and planar). Agreement between modalities for the detection of bone metastases was good (κ = 0.73 to 0.77). Three (3.1%) patients had visceral metastases on SPECT/CT, two of which were detected on SPECT and planar. There was good agreement between modalities for the TNM staging of patients (κ = 0.70 to 0.88). No metastatic lesions were missed on the limited FOV images. Conclusion When PS scintigraphy is performed, SPECT/CT is recommended. However, the lack of SPECT/CT capabilities should not preclude the use of PS in the presence of limited resources, as both planar and SPECT imaging are adequate and will correctly stage most PCa patients. Furthermore, time-based optimisations are achievable by limiting the FOV to exclude the distal lower limbs.

Neuroendocrine tumors (NETs) are not commonly diagnosed in children. Metastatic NETs tend to have poor outcomes, and this is seen in adult and pediatric populations. The role of somatostatin receptor imaging using [ 68 Ga]Ga-DOTA-TATE for imaging and peptide receptor radionuclide therapy (PRRT) with [ 177 Lu]Lu-DOTA-TATE in children is currently not well established. The guidelines for treating pediatric neuroendocrine tumors are still lacking. Extensive trials have been conducted in adult patients and have demonstrated improved survival in metastatic NETs with PRRT using [ 177 Lu]Lu-DOTA-TATE. We present two pediatric patients with metastatic NETs who were imaged with [ 68 Ga]Ga-DOTA-TATE PET/CT and treated with [ 177 Lu]Lu-DOTA-TATE therapy.

Introduction: Transplant renography with radionuclides has been in use for decades owing to its ability to assess renal perfusion, function, and drainage. An uncommon but significant complication post renal transplantation is a urinary leak. Ultrasonography is commonly used for posttransplant assessment, however in the diagnosis of urinary leaks, often cannot differentiate between peritoneal fluid and urine, this is an added benefit of utilizing transplant renography. We present two pediatric patients who had [99mTc] Tc-MAG3 renography day 1 posttransplant and where SPECT/CT assisted in differentiating a urinary leak from a displaced urinary bladder.

Society of Nuclear Medicine and Molecular Imaging, Reston, Virginia; Australian and New Zealand Society of Nuclear Medicine, Vermont South, Victoria, Australia; Australasian Association of Nuclear Medicine Specialists, Balmain, New South Wales, Australia; British Society for Nanomedicine, Liverpool, United Kingdom; Asia Oceania Federation of Nuclear Medicine and Biology, Osaka, Japan; Japanese Society of Nuclear Medicine, Tokyo, Japan; Society of Nuclear Medicine, India, Mumbai, India; Arab Society of Nuclear Medicine, Beirut, Lebanon; Canadian Association of Nuclear Medicine, Rosem ere, Quebec, Canada; European Association of Nuclear Medicine, Vienna, Austria; International Atomic Energy Agency, Vienna, Austria; Korean Society of Nuclear Medicine, Seoul, Korea; and South African Society of Nuclear Medicine, Cape Town, South Africa

Breast cancer in women of African descent tends to be more aggressive with poorer prognosis. This is irrespective of the molecular subtype. [18F]FDG PET/CT metrics correlate with breast cancer aggressiveness based on molecular subtype. This study investigated the differences in [18F]FDG PET/CT metrics of locally advanced invasive ductal carcinoma (IDC) among different racial groups and molecular subtypes. Qualitative and semiquantitative readings of [18F]FDG PET/CT acquired in women with locally advanced IDC were performed. Biodata including self-identified racial grouping and histopathological data of the primary breast cancer were retrieved. Statistical analysis for differences in SUVmax, MTV and TLG of the primary tumour and the presence of regional and distant metastases was conducted based on molecular subtype and race. The primary tumour SUVmax, MTV, TLG and the prevalence of distant metastases were significantly higher in Black patients compared with other races (p < 0.05). The primary tumour SUVmax and presence of distant metastases in the luminal subtype and the primary tumour SUVmax and TLG in the basal subtype were significantly higher in Black patients compared with other races (p < 0.05). The significantly higher PET parameters in Black patients with IDC in general and in those with luminal and basal carcinoma subtypes suggest a more aggressive disease phenotype in this race.

Gallium-68 fibroblast activation protein inhibitor [( 68 Ga)Ga-FAPI] is a new radiopharmaceutical positioning itself as the preferred agent in patients with malignant tumours, competing with 2-Deoxy-2-[18F]fluoro-d-glucose [2-( 18 F)FDG] using positron emission tomography (PET). While imaging oncology patients with [ 68 Ga]Ga-FAPI PET, incidental uptake of [ 68 Ga]Ga-FAPI has been detected in the myocardium. This review summarises original research studies associating the visualisation of FAPI-based tracers in the myocardium with underlying active cardiovascular disease.

Personalised dosimetry based on molecular imaging is a field that has grown exponentially in the last decade due to the increasing success of Radioligand Therapy (RLT). Despite advances in imaging-based 3D dose estimation, the administered dose of a therapeutic radiopharmaceutical for RLT is often non-personalised, with standardised dose regimens administered every 4–6 weeks. Biodosimetry markers, such as chromosomal aberrations, could be used alongside image-based dosimetry as a tool for individualised dose estimation to further understand normal tissue toxicity and refine the administered dose. In this review we give an overview of biodosimetry markers that are used for blood dose estimation, followed by an overview of their current results when applied in RLT patients. Finally, an in-depth discussion will provide a perspective on the potential for the use of biodosimetry in the nuclear medicine clinic.

Introduction: The NETPET grading system is a quantitative method comparing somatostatin receptor expression with glucose metabolism on PET-CT to ascertain eligibility for PRRT. The aim was to assess the utility of the NETPET grading system in the identification of suitable patients for Lutetium-177 DOTATATE peptide receptor radionuclide therapy (PRRT).

Introduction: 99mTc MDP bone scintigraphy has utility in staging prostate cancer where access to more accurate modalities, such as PSMA ligand imaging, is limited by cost or lacking infrastructure.

This review paper will discuss the use of positron emission tomography/computed tomography (PET/CT) in paediatric oncology. Functional imaging with PET/CT has proven useful to guide treatment by accurately staging disease and limiting unnecessary treatments by determining the metabolic response to treatment. 18F-Fluorodeoxyglucose (2-[18F]FDG) PET/CT is routinely used in patients with lymphoma. We highlight specific considerations in the paediatric population with lymphoma. The strengths and weaknesses for PET/CT tracers that compliment Meta-[123I]iodobenzylguanidine ([123I]mIBG) for the imaging of neuroblastoma are summarized. 2-[18F]FDG PET/CT has increasingly been used in the staging and evaluation of disease response in sarcomas. The current recommendations for the use of PET/CT in sarcomas are given and potential future developments and highlighted. 2-[18F]FDG PET/CT in combination with conventional imaging is currently the standard for disease evaluation in children with Langerhans-cell Histiocytosis (LCH) and the non-LCH disease spectrum. The common pitfalls of 2-[18F]FDG PET/CT in this setting are discussed.

ABSTRACT:Prostate-specific membrane antigen (PSMA) is expressed on the neovasculature as well as to some extent on the glioblastoma cells. With this background, we report the case of a 34-year-old man with recurrent glioblastoma who was treated with 2 cycles of low-dose [ 177 Lu]Lu-PSMA after exhausting all available treatment options in the state sector. Baseline imaging demonstrated intense PSMA signal in the known lesion, which was amenable to therapy. The prospect of [ 177 Lu]Lu-PSMA-based therapy for glioblastoma is warranted going forward.

Introduction: Groote Schuur Hospital (GSH) was one of the only state hospitals in South Africa that did not have a PET/CT facility onsite that is required to support clinical work which includes planning for theragnostic applications.