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Background: The delineation of intraprostatic lesions is vital for correct delivery of focal radiotherapy boost in patients with prostate cancer (PC). Errors in the delineation could translate into reduced tumour control and potentially increase the side effects. The purpose of this study is to compare PET-based delineation methods with histopathology. Materials and methods: The study population consisted of 15 patients with confirmed high-risk PC intended for prostatectomy. [68Ga]-PSMA-PET/MR was performed prior to surgery. Prostate lesions identified in histopathology were transferred to the in vivo [68Ga]-PSMA-PET/MR coordinate system. Four radiation oncologists manually delineated intraprostatic lesions based on PET data. Various semi-automatic segmentation methods were employed, including absolute and relative thresholds, adaptive threshold, and multi-level Otsu threshold. Results: The gross tumour volumes (GTVs) delineated by the oncologists showed a moderate level of interobserver agreement with Dice similarity coefficient (DSC) of 0.68. In comparison with histopathology, manual delineations exhibited the highest median DSC and the lowest false discovery rate (FDR) among all approaches. Among semi-automatic approaches, GTVs generated using standardized uptake value (SUV) thresholds above 4 (SUV > 4) demonstrated the highest median DSC (0.41), with 0.51 median lesion coverage ratio, FDR of 0.66 and the 95th percentile of the Hausdorff distance (HD95%) of 8.22 mm. Interpretation: Manual delineations showed a moderate level of interobserver agreement. Compared to histopathology, manual delineations and SUV > 4 exhibited the highest DSC and the lowest HD95% values. The methods that resulted in a high lesion coverage were associated with a large overestimation of the size of the lesions.

Background: The delineation of intraprostatic lesions is vital for correct delivery of focal radiotherapy boost in patients with prostate cancer (PC). Errors in the delineation could translate into reduced tumour control and potentially increase the side effects. The purpose of this study is to compare PET-based delineation methods with histopathology., Materials and Methods: The study population consisted of 15 patients with confirmed high-risk PC intended for prostatectomy. [68Ga]-PSMA-PET/MR was performed prior to surgery. Prostate lesions identified in histopathology were transferred to the in vivo [68Ga]-PSMA-PET/MR coordinate system. Four radiation oncologists manually delineated intraprostatic lesions based on PET data. Various semi-automatic segmentation methods were employed, including absolute and relative thresholds, adaptive threshold, and multi-level Otsu threshold., Results: The gross tumour volumes (GTVs) delineated by the oncologists showed a moderate level of interobserver agreement with Dice similarity coefficient (DSC) of 0.68. In comparison with histopathology, manual delineations exhibited the highest median DSC and the lowest false discovery rate (FDR) among all approaches. Among semi-automatic approaches, GTVs generated using standardized uptake value (SUV) thresholds above 4 (SUV > 4) demonstrated the highest median DSC (0.41), with 0.51 median lesion coverage ratio, FDR of 0.66 and the 95th percentile of the Hausdorff distance (HD95%) of 8.22 mm., Interpretation: Manual delineations showed a moderate level of interobserver agreement. Compared to histopathology, manual delineations and SUV > 4 exhibited the highest DSC and the lowest HD95% values. The methods that resulted in a high lesion coverage were associated with a large overestimation of the size of the lesions.

A 61-year-old male patient, who had undergone radical prostatectomy, underwent 68Ga labeled prostate-specific membrane antigen (PSMA) positron emission tomography/computerized tomography (PET/CT) for evaluation of suspected biochemical recurrence of prostate cancer (PCa). PET/CT scan showed increased 68Ga PSMA expressions in hypodense mass lesions in both adrenal gland localizations. An adrenal gland tru-cut biopsy was performed for the right side, which showed poor-differentiated carcinoma metastases associated with the patient's high-grade PCa. As far as we could determine based on an extensive literature search, this is the second case in which isolated adrenal metastasis was detected by 68Ga PSMA PET/CT study in a patient with PCa. [ABSTRACT FROM AUTHOR]

We present the case of a patient with newly diagnosed high-risk prostate cancer. The patient underwent nephrectomy for renal cell carcinoma (RCC) in 2009. The prostate-specific membrane antigen (PSMA) scan revealed a primary tumor with seminal vessel involvement, PSMA-positive regional lymph nodes, several nodular lung lesions with mild PSMA uptake, PSMA-positive mediastinal lymph nodes, and a PSMA-positive mass in the pancreatic head. Ultrasound-guided biopsy was performed for the pancreatic lesions revealing metastasis from a RCC. Simultaneous treatment for prostate cancer and metastatic RCC was initiated. To separate metastatic sites for both primaries, we attempted to use fluorodeoxyglucose positron emission tomography/computed tomography, which was moderately positive for the pancreatic mass but not for the other locations. RCC is a 68Ga PSMA-positive tumor; the synchronous combination of RCC with prostate cancer can be confusing and requires more complex clinical interpretation. [ABSTRACT FROM AUTHOR]

Background: Patients diagnosed with dominant intraprostatic lesions (DIL) may need radiation doses over than 80 Gy. Dose-painting by contours (DPC) is a useful technique which helps the patients. Dose-painting approach need to be evaluated. Objective: To evaluate the DCP technique in the case of boosting the DILs by radiobiological parameters, tumor control probability (TCP), and normal tissue complication probability (NTCP) via PET/CT images traced by 68Ga-PSMA.Material and Methods: In this analytical study, 68Ga-PSMA PET/CT images were obtained from patients with DILs that were delineated using the Fuzzy c-mean (FCM) algorithm and thresholding methods. The protocol of therapy included two phases; at the first phase (ph1), a total dose of 72 Gy in 36 fractions were delivered to the planning target volume (PTV1); the seconds phase consisted of the application of variable doses to the PTV2. Moreover, two concepts were also considered to calculate the TCP using the Zaider-Minerbo model. Results: The lowest volume in DILs belonged to the DIL1 extracted by the FCM method. According to dose-volume parameters of the rectum and bladder, by the increase in the PTV dose higher than 92 Gy, the amounts of rectum and bladder doses are increased. There was no difference between the TCPs of DILs at doses higher than 86 Gy and 100 Gy for ordinary and high clone density, respectively. Conclusion: Consequently, our dose-painting approach for DILs, extracted by the FCM method via PET/CT images, can reduce the total dose for prostate radiation with 100% tumor control and less normal tissue complications.

Prostate-specific membrane antigen (PSMA) is a transmembrane protein with overexpression in most prostate cancer cells. Gallium-68-(68Ga) PSMA positron emission tomography/computed tomography (PET/CT) imaging is a game-changer in the management of prostate cancer. 68Ga PSMA PET/CT scan is advanced and a promising radioligand has high sensitivity in determining lesions of prostate cancer with a high tumor to background ratio. The most common areas of metastasis are the bone and pelvic lymph nodes. The prognosis of prostate cancer is mainly determined by the status of metastases. The presence and the localization of metastases affects treatment planning. In our cases, we presented some examples of uncommon sites of metastases such as the brain, adrenal glands, penis and orbit. Improvements in imaging techniques, such as 68Ga PSMA PET/CT have led to the possibility to make more determi nation of rare metastase sites in prostate cancer patients. [ABSTRACT FROM AUTHOR]

The clinical utility of gallium 68 (68Ga)-PSMA PET for the diagnosis and management of prostate cancer is driven in part by radioisotope availability and production costs. This study evaluates the equivalence between the two manufacturing processes for 68Ga-PSMA: 68Ga-PSMA-cyclotron (from a solid target) and 68Ga-PSMA-generator. A prospective, single-arm, single-institution non-randomized study was conducted where 16 patients with prostate adenocarcinoma underwent PET/CTs consecutively within 12 to 48 hours with each type of manufactured 68Ga-PSMA between December 2020 and June 2021. The intraclass correlation coefficients suggested acceptable reliability in all lesion parameters (ICC > 0.70). Bland-Altman analysis demonstrated acceptable bias levels for all lesion parameters. Thereby 68Ga-cyclotron (solid target) and 68Ga-generator production methods tagged to the same PSMA ligand resulted in scans which were deemed to be equivalent in detecting PSMA+ lesions in our study. As cyclotron-produced, solid- target 68Ga can be made in large (Ci) quantities, it is a promising tool for future application in 68Ga-PSMA PET scans with the potential to decrease radiotracer production costs and increase isotope availability.

Objective(s): Prostate-specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography (PET/CT) is an emerging modality to detect metastatic disease in patients with prostate cancer (PCa). This prospective study aimed to evaluate the role of [68Ga]-PSMA PET/CT in the initial workup of intermediate and high-risk PCa .Methods: Twenty-five patients with newly transrectal ultrasound biopsy-proven, untreated intermediate- and high-risk PCa (mean age, 68.5±6.2 years; range 55–83 years) were enrolled in this prospective study between September 2018 and June 2020 and underwent a [68Ga]-PSMA PET/CT examination. All images were analyzed both visually and semiquantitatively by measuring the maximum standardized uptake value (SUVmax) of the primary prostatic tumor and metastatic lesions. The diagnostic sensitivity of [68Ga]-PSMA PET/CT for the diagnosis of PCa was established by histopathology as the reference standard. The associations between SUVmax of the primary tumors and prostate-specific antigen (PSA) levels, Gleason scores (GSs), and metastatic extent of the disease were studied.Results: All patients had a positive [68Ga]-PSMA PET/CT exam. Seventeen patients (58%) showed [68Ga]-PSMA avidity in both prostate lobes and 8 (32%) had unilateral uptake. SUVmax in the primary tumor significantly correlated with serum PSA values (r=0.57, P=0.003). PSMA PET/CT depicted regional lymph node metastases in 32% of patients, distant lymph node metastases in 20%, osseous metastases in 16% and pulmonary metastases in 8% of patients. Sixty percent of PSMA-positive bone metastases and 21.4% of intraprostatic tumoral lesions were missed on the contemporaneous bone scintigraphy and magnetic resonance imaging, respectively.Conclusion: [68Ga]-PSMA PET/CT shows promise as a valuable imaging modality with high diagnostic sensitivity in the setting of intermediate and high-risk PCa. Moreover, the SUVmax of the primary tumor has a positive correlation with PSA levels at the time of the scan.

Purpose: ChatGPT has recently been the subject of many studies, and its responses to medical questions have been successful. We examined ChatGPT-4’s evaluation of structured 68Ga prostate-specific membrane antigen (PSMA) PET/CT reports of newly diagnosed prostate cancer patients.68Ga PSMA PET/CT reports of 164 patients were entered to ChatGPT-4. ChatGPT-4 was asked to respond the following questions according to the PET/CT reports: 1-Has the cancer in the prostate extended to organs adjacent to the prostate? 2-Has the cancer in the prostate spread to neighboring lymph nodes? 3-Has the cancer in the prostate spread to lymph nodes in distant areas? 4-Has the cancer in the prostate spread to the bones? 5-Has the cancer in the prostate spread to other organs? ChatGPT-4’s responses were scored on a Likert-type scale for clarity and accuracy.The mean scores for clarity were 4.93 ± 0.32, 4.95 ± 0.25, 4.96 ± 0.19, 4.99 ± 0.11, and 4.96 ± 0.30, respectively. The mean scores for accuracy were 4.87 ∓ 0.61, 4.87 ∓ 0.62, 4.79 ± 0.83, 4.96 ± 0.25, and 4.93 ± 0.45, respectively. Patients with distant lymphatic metastases had a lower mean accuracy score than those without (4.28 ± 1.45 vs. 4.94 ± 0.39; p < 0.001). ChatGPT-4’s responses in 13 patients (8%) had the potential for harmful information.ChatGPT-4 successfully interprets structured 68Ga PSMA PET/CT reports of reports of newly diagnosed prostate cancer patients. However, it is unlikely that ChatGPT-4 evaluations will replace physicians’ evaluations today, especially since it can produce fabricated information.Methods: ChatGPT has recently been the subject of many studies, and its responses to medical questions have been successful. We examined ChatGPT-4’s evaluation of structured 68Ga prostate-specific membrane antigen (PSMA) PET/CT reports of newly diagnosed prostate cancer patients.68Ga PSMA PET/CT reports of 164 patients were entered to ChatGPT-4. ChatGPT-4 was asked to respond the following questions according to the PET/CT reports: 1-Has the cancer in the prostate extended to organs adjacent to the prostate? 2-Has the cancer in the prostate spread to neighboring lymph nodes? 3-Has the cancer in the prostate spread to lymph nodes in distant areas? 4-Has the cancer in the prostate spread to the bones? 5-Has the cancer in the prostate spread to other organs? ChatGPT-4’s responses were scored on a Likert-type scale for clarity and accuracy.The mean scores for clarity were 4.93 ± 0.32, 4.95 ± 0.25, 4.96 ± 0.19, 4.99 ± 0.11, and 4.96 ± 0.30, respectively. The mean scores for accuracy were 4.87 ∓ 0.61, 4.87 ∓ 0.62, 4.79 ± 0.83, 4.96 ± 0.25, and 4.93 ± 0.45, respectively. Patients with distant lymphatic metastases had a lower mean accuracy score than those without (4.28 ± 1.45 vs. 4.94 ± 0.39; p < 0.001). ChatGPT-4’s responses in 13 patients (8%) had the potential for harmful information.ChatGPT-4 successfully interprets structured 68Ga PSMA PET/CT reports of reports of newly diagnosed prostate cancer patients. However, it is unlikely that ChatGPT-4 evaluations will replace physicians’ evaluations today, especially since it can produce fabricated information.Results: ChatGPT has recently been the subject of many studies, and its responses to medical questions have been successful. We examined ChatGPT-4’s evaluation of structured 68Ga prostate-specific membrane antigen (PSMA) PET/CT reports of newly diagnosed prostate cancer patients.68Ga PSMA PET/CT reports of 164 patients were entered to ChatGPT-4. ChatGPT-4 was asked to respond the following questions according to the PET/CT reports: 1-Has the cancer in the prostate extended to organs adjacent to the prostate? 2-Has the cancer in the prostate spread to neighboring lymph nodes? 3-Has the cancer in the prostate spread to lymph nodes in distant areas? 4-Has the cancer in the prostate spread to the bones? 5-Has the cancer in the prostate spread to other organs? ChatGPT-4’s responses were scored on a Likert-type scale for clarity and accuracy.The mean scores for clarity were 4.93 ± 0.32, 4.95 ± 0.25, 4.96 ± 0.19, 4.99 ± 0.11, and 4.96 ± 0.30, respectively. The mean scores for accuracy were 4.87 ∓ 0.61, 4.87 ∓ 0.62, 4.79 ± 0.83, 4.96 ± 0.25, and 4.93 ± 0.45, respectively. Patients with distant lymphatic metastases had a lower mean accuracy score than those without (4.28 ± 1.45 vs. 4.94 ± 0.39; p < 0.001). ChatGPT-4’s responses in 13 patients (8%) had the potential for harmful information.ChatGPT-4 successfully interprets structured 68Ga PSMA PET/CT reports of reports of newly diagnosed prostate cancer patients. However, it is unlikely that ChatGPT-4 evaluations will replace physicians’ evaluations today, especially since it can produce fabricated information.Conclusion: ChatGPT has recently been the subject of many studies, and its responses to medical questions have been successful. We examined ChatGPT-4’s evaluation of structured 68Ga prostate-specific membrane antigen (PSMA) PET/CT reports of newly diagnosed prostate cancer patients.68Ga PSMA PET/CT reports of 164 patients were entered to ChatGPT-4. ChatGPT-4 was asked to respond the following questions according to the PET/CT reports: 1-Has the cancer in the prostate extended to organs adjacent to the prostate? 2-Has the cancer in the prostate spread to neighboring lymph nodes? 3-Has the cancer in the prostate spread to lymph nodes in distant areas? 4-Has the cancer in the prostate spread to the bones? 5-Has the cancer in the prostate spread to other organs? ChatGPT-4’s responses were scored on a Likert-type scale for clarity and accuracy.The mean scores for clarity were 4.93 ± 0.32, 4.95 ± 0.25, 4.96 ± 0.19, 4.99 ± 0.11, and 4.96 ± 0.30, respectively. The mean scores for accuracy were 4.87 ∓ 0.61, 4.87 ∓ 0.62, 4.79 ± 0.83, 4.96 ± 0.25, and 4.93 ± 0.45, respectively. Patients with distant lymphatic metastases had a lower mean accuracy score than those without (4.28 ± 1.45 vs. 4.94 ± 0.39; p < 0.001). ChatGPT-4’s responses in 13 patients (8%) had the potential for harmful information.ChatGPT-4 successfully interprets structured 68Ga PSMA PET/CT reports of reports of newly diagnosed prostate cancer patients. However, it is unlikely that ChatGPT-4 evaluations will replace physicians’ evaluations today, especially since it can produce fabricated information. [ABSTRACT FROM AUTHOR]

Abstract Background Current guidelines highlight the importance of accurate staging in the management and prognostication of high risk primary prostate cancer. Conventional radiologic imaging techniques are insufficient to reliably detect lymph node metastases in prostate cancer. Despite promising results, there is limited published data on the diagnostic accuracy of PSMA PET-CT to assess local nodal metastases prior to radical prostatectomy. This study aims to assess the diagnostic efficacy of 68Ga PSMA PET-CT in local lymph node staging of high risk primary prostate cancer when compared to histopathological findings following radical prostatectomy with pelvic lymph node dissection. Methods We retrospectively analysed consecutive patients with high risk primary prostate cancer referred by urologists for primary staging PSMA PET-CT using a 68Ga-labeled PSMA ligand, Glu-NH-CO-NHLys-(Ahx)-[HBEDD-CC], from October 2015 to October 2017. The scans of patients who underwent radical prostatectomy with pelvic lymph node dissection were interpreted by the consensus reading of two experienced nuclear medicine physicians blinded to clinical and histopathological data. The contemporaneous records of the referring urologists were retrospectively reviewed for noteworthy unexpected PET findings that altered their personal preference for surgical management. Results Seventy-one patients were recruited and analysed. PSMA PET-CT showed findings compatible with local disease in 47 patients (66.2%), lymph node metastases in 10 patients (14.1%) and distant metastases in 14 patients (19.7%). Twenty-eight patients (twenty-seven of whom had local disease only) underwent surgery yielding 214 lymph nodes, all of which were negative on histopathological analysis. On a node-based analysis, 213 of 214 lymph nodes were accurately identified as negative for disease with a negative predictive value of 100%. 11 patients had unexpected PET findings contemporaneously documented by urologists to alter their preference for surgical management. Conclusions PSMA PET-CT appears to have a high negative predictive value for local lymph node metastases in high risk primary prostate cancer when compared to histopathological findings following radical prostatectomy with pelvic lymph node dissection.

Aim: To examine predictive markers for high detection rates of 68Ga PSMA-PET/CT in biochemical recurrence (BR) prostate cancer (PCa) patients with low PSA levels. Material and Method: This trial was planned as a retrospective single center study. Patients with BR prostat cancer were included. PSA levels of all patients were lower 2 μg/l. Results: Totally thirty-two men patients with BR PCa were included in this study. 18 (56.3%) patients underwent radical prostatectomy and 14 (43.7%) patients curative intense radiotherapy. The number of patients received adjuvant maximal androgen blokage (MAB) treatment was 15 (46.9%). Median PSA levels was calculated 1.03 μg/l 17 (53.1%) of patients had

Prostate cancer is the second most common malignancy in men worldwide, with a good prognosis when is detected and treated in early stages, but, when it presents progression to castration-resistant metastatic prostate cancer, most of the cases will have bone metastasis, decreasing the quality of life and life expectancy. For the evaluation of the disease in the routinary clinical practice, 68Ga-PSMA PET/CT, among others is a valuable tool for the evaluation of the disease extension. 68Ga-PSMA PET/CT detects the presence of PSMA receptor in the tumoral tissue, but also has physiologic uptake in certain organs, such as liver, spleen, intestine, kidneys, lacrimal and salivary glands. Total or partial absence of uptake in those organs is rare and may be due to a high metastatic tumor burden, a phenomenon originally described in bone scintigraphy as super scan. We describe a case series of seven patients with prostate cancer from the National Institute of Cancerology in Colombia, in which a super scan pattern was found in the evaluation with 68Ga-PSMA PET/ CT, proposing the suppression of uptake in the intestine, liver, spleen, lacrimal and salivary glands as the main criteria for its definition, and showing that renal uptake persists in most cases, considering that, unlike the super scan in conventional bone scintigraphy, this is not a criterion necessary for its definition in the study with 68Ga-PSMA. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to evaluate the effectiveness of routine additional acquisitions for lower extremity in the diagnosis and treatment of patients undergoing 68Ga prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT). Methods: The files of 59 prostate cancer patients who underwent additional acquisition of the lower extremities in addition to the vertex-upper thigh in 68Ga PSMA PET/CT studies were included in the study. In our study, patients with both lower limb acquisition on clinical suspicion and with routine lower limb acquisition were included. Along with the difference in the effectiveness of the lower limb acquisition between these two arms, the efficacy and clinical utility of the additional acquisiton were evaluated in the entire sample. Results: The rate of metastasis detected in the group with lower limb acquisiton with clinical suspicion (31.1%) is higher than in the other group (7.6%). However, metastases detected in both groups do not cause changes in the treatment. Conclusion: Considering the loss of time caused by additional acquisitons in the clinic, the radiation dose exposure of the patient and the outcomes in this study, it may be possible to say that the lower extremity acquisitons are not effective. [ABSTRACT FROM AUTHOR]

Aim: To assess whether clinical prostate cancer (PCA) related factors and therapy status can predict the degree of tracer uptake on [ 68 Ga]PSMA-HBED-CC PET/CT., Materials & Methods: We retrospectively studied 124 patients with recurrent an/or metastatic PCA who underwent [ 68 Ga]PSMAHBED-CC PET/CT. The maximum standardized uptake value (SUVmax) was determined in the prostate bed as well as in three size categories (≤ 5 mm, > 5-15 mm, > 15 mm) in pelvic lymph node, extrapelvic lymph node, bone and visceral metastases., Results: Significant positive correlations between lesion size and SUVmax were found in pelvic lymph node metastases > 5 -≤15 mm (Spearmans rho = 0.502, p = 0.002) as well as in extrapelvic lymph node metastases5 mm (rho = 0.314, p = 0.033) and > 5 ≤-15 mm (rho = 0.614, p < 0.001). SUVmax tended to be higher in the largest diameter category in each anatomic station than in the middle and lower categories. We were unable to find evidence for a relationship between SUVmax and PSA, PSAdt, Gleason score, androgen deprivation therapy, radiation therapy or chemotherapy status., Conclusion: Measured tracer uptake in [ 68 Ga]PSMA-HBED-CC PET/CT in patients with recurrent/metastasized prostate cancer is significantly influenced by lesion size as a result of partial volume effects in the very small lesions. Clinical indicators of aggressive prostate cancer behaviour such as PSA levels, PSA doubling time or the Gleason score of the primary tumour, as well as the androgen deprivation therapy, radiation therapy or chemotherapy status are not related to measured tracer uptake. ZIEL:: Beantwortung der Frage ob klinisch bestimmbare Faktoren und Therapiestatus bei Prostatakarzinom (PCA) eine Vorhersage zur Traceranreicherung in [ 68 Ga]PSMA-HBED-CC PET/CT liefern können.Material & Methoden: 124 Patienten mit rezidiviertem und/oder metastasiertem PCA die [ 68 Ga]PSMA-HBED-CC PET/CT untergingen, wurden retrospektiv untersucht. Der maximum Standardized Uptake Value (SUVmax) wurde in der Prostataloge gemessen sowie in drei Größen-Kategorien ( 5 mm, > 5-15 mm, > 15 mm) in Metastasen in den pelvinen Lymphknoten-, extrapelvinen Lymphknoten-, Knochen- und viszeralen Metastasen., Ergebnisse: Signifikant positive Korrelationen zwischen Läsionsgröße und SUVmax wurden in pelvinen Lymphknotenmetastasen > 5 -≤15 mm (Spearmans rho = 0.502, p = 0.002), extrapelvinen Lymphknotenmetastasen5 mm (rho = 0.314, p = 0.033) und > 5 -≤15 mm (rho = 0.614, p < 0.001) gefunden. Für jede anatomische Lokalisation wurde ein höherer Wert SUVmax innerhalb der größten Kategorie verglichen zu mittleren und kleinsten Kategorie gefunden., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Schattauer GmbH.)

A 67-year-old male patient had undergone total gastrectomy and Roux-en-Y eso-jejunostomy 3 years ago for the treatment of tubular adenocarcinoma located at the corpus of the stomach. The patient was diagnosed with Gleason score 8 (4+4) metastatic prostate cancer during the follow-up period and received hormone therapy. Owing to his elevated prostate-specific antigen levels (77 ng/mL), his clinician referred him gallium-68 (68Ga) prostate-specific membrane antigen 11 (PSMA) positron emission tomography/computed tomography (PET/CT) for restaging. PET/CT showed multiple 68Ga PSMA receptor-positive skeletal lesions and linear PSMA activity at the eso-jejunostomy junction. He was then referred to undergo 18fluorine-fluorodeoxyglucose (18F-FDG) PET/CT to screen for gastric carcinoma recurrence. PET/CT images demonstrated no 18F-FDG avid lesion. However, endoscopy and biopsy performed with samples from the eso-jejunostomy junction revealed superficial benign squamous epithelial fragments. [ABSTRACT FROM AUTHOR]

Objective(s): Prostate-specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography (PET/CT) is an emerging modality to detect metastatic disease in patients with prostate cancer (PCa). This prospective study aimed to evaluate the role of [68Ga]-PSMA PET/CT in the initial workup of intermediate and high-risk PCa . Methods: Twenty-five patients with newly transrectal ultrasound biopsy-proven, untreated intermediate- and high-risk PCa (mean age, 68.5±6.2 years; range 55–83 years) were enrolled in this prospective study between September 2018 and June 2020 and underwent a [68Ga]-PSMA PET/CT examination. All images were analyzed both visually and semiquantitatively by measuring the maximum standardized uptake value (SUVmax) of the primary prostatic tumor and metastatic lesions. The diagnostic sensitivity of [68Ga]-PSMA PET/CT for the diagnosis of PCa was established by histopathology as the reference standard. The associations between SUVmax of the primary tumors and prostate-specific antigen (PSA) levels, Gleason scores (GSs), and metastatic extent of the disease were studied. Results: All patients had a positive [68Ga]-PSMA PET/CT exam. Seventeen patients (58%) showed [68Ga]-PSMA avidity in both prostate lobes and 8 (32%) had unilateral uptake. SUVmax in the primary tumor significantly correlated with serum PSA values (r=0.57, P=0.003). PSMA PET/CT depicted regional lymph node metastases in 32% of patients, distant lymph node metastases in 20%, osseous metastases in 16% and pulmonary metastases in 8% of patients. Sixty percent of PSMA-positive bone metastases and 21.4% of intraprostatic tumoral lesions were missed on the contemporaneous bone scintigraphy and magnetic resonance imaging, respectively. Conclusion: [68Ga]-PSMA PET/CT shows promise as a valuable imaging modality with high diagnostic sensitivity in the setting of intermediate and high-risk PCa. Moreover, the SUVmax of the primary tumor has a positive correlation with PSA levels at the time of the scan. [ABSTRACT FROM AUTHOR]