Neo P. Mokgoro

68 Ga-PSMA imaging of metastatic breast cancer

Ga-labelled prostate-specific membrane antigen (PSMA) is rapidly emerging as a significant step forward in the diagnosis of recurrent prostate cancer, based on the fact that PSMA is a type II transmembrane protein with high expression in prostate carcinoma cells [1, 2]. Recently it has been demonstrated to accumulate in metastatic clear-cell renal cell carcinoma [3] and interestingly several studies have provided evidence that PSMA is also expressed in the tumour-associated vasculature of primary breast cancers and distant metastases [4, 5]. We report the case of a 33-year-old woman with metastatic breast carcinoma who underwent Ga-PSMA and F-FDG PET/CT imaging for restaging and evaluation of the most appropriate therapeutic option. Images demonstrated intense and extensive skeletal uptake in the axial and appendicular skeleton with liver metastases. Concordance of Ga-PSMA and F-FDG lesions suggests that Ga-PSMA may provide helpful prognostic information. Furthermore, Ga-PSMA-avid metastatic sites may in future aid in selecting tumours with high PSMA expression for PSMA-directed therapy.

Correlation between serum calcium levels and dual-phase 99mTc-sestamibi parathyroid scintigraphy in primary hyperparathyroidism

Aim:  The goal of the study is to correlate serum calcium levels with the results of dual‐phase 99mTc‐sestamibi parathyroid scintigraphy to find the best cut‐off level of the serum calcium that correlates with a positive presurgery.

Diagnostic sensitivity of Tc-99m HYNIC PSMA SPECT/CT in prostate carcinoma: A comparative analysis with Ga-68 PSMA PET/CT

Emerging data from published studies are demonstrating the superiority of Ga‐68 PSMA PET/CT imaging in prostate cancer. However, the low yield of the Ge‐68/Ga‐68 from which Gallium‐68 is obtained and fewer installed PET/CT systems compared to the SPECT imaging systems may limit its availability. We, therefore, evaluated in a head‐to‐head comparison, the diagnostic sensitivity of Ga‐68 PSMA PET/CT and Tc‐99m PSMA SPECT/CT in patients with prostate cancer.

68Ga-PSMA-HBED-CC PET/CT imaging in Black versus White South African patients with prostate carcinoma presenting with a low volume, androgen-dependent biochemical recurrence: a prospective study

Objective To compare the diagnostic accuracy of 68Ga-prostate-specific membrane antigen (PSMA)-HBED-CC PET/computed tomography (CT) imaging for the detection of androgen-dependent recurrent prostate carcinoma (ADPC) in Black South Africans (BSAs) versus White South Africans (WSAs) with increasing serum prostate-specific antigen (PSA) values below or equal to 10 ng/ml. Patients and methods A total of 61 patients with ADPC were prospectively included in the study (mean age: 66.7 years): 38 WSAs and 23 BSAs. 68Ga-PSMA-HBED-CC PET/CT imaging results obtained were related to serum PSA levels and to ethnicity. Results A total of 41 (67%) patients had a positive 68Ga-PSMA-HBED-CC scan result. 68Ga-PSMA-HBED-CC PET/CT positivity was significantly higher in patients with PSA values more than 2 ng/ml [32/38 (84%) patients] when compared with patients with PSA values less than 0.5 ng/ml [6/11 (55%) patients] or PSA values of 0.5–2 ng/ml [3/12 (25%) patients] (P=0.0001). Mean PSA values proved not significantly different in patients presenting with extrapelvic involvement when compared with those with intrapelvic involvement or between patients who presented with bone involvement versus those who did not on 68Ga-PSMA-HBED-CC PET/CT) (P≥0.147). Age, Gleason-scores, median PSA values, the frequency of a positive scan result, the frequency of bone involvement, and extrapelvic involvement proved similar in WSAs and BSAs (P≥0.417). Conclusion 68Ga-PSMA-HBED-CC PET/CT imaging identified a recurrence in 67% of the patients under study. Higher PSA levels were associated with 68Ga-PSMA-HBED-CC PET/CT positivity and the detection rate. Imaging results obtained proved similar in BSAs and WSAs, suggesting that the tumor burden and growth rate of ADPC are similar in both races.

Higher preablative serum thyroid-stimulating hormone level predicts radioiodine ablation effectiveness in patients with differentiated thyroid carcinoma.

Introduction Radioiodine ablation of remnant thyroid tissue is an important adjuvant therapy of differentiated thyroid carcinoma (DTC) after thyroidectomy. Elevated serum thyroid-stimulating hormone (TSH) level is necessary for successful ablation. The optimum level of serum TSH level necessary for successful radioiodine ablation of well-DTC is, however, yet to be defined. We aimed to determine whether higher serum TSH level will result in a better rate of complete ablation of well-DTC using iodine-131 (131I) following initial thyroidectomy. Patients and methods A total of 109 patients with differentiated thyroid cancer were divided into four treatment groups on the basis of serum TSH levels. They were followed up from 6 to 12 months after treatment with stimulated serum thyroglobulin level and a diagnostic whole-body scan with radioactive iodine 131I to determine early response. Results Sixty-four patients had papillary thyroid carcinoma, whereas 45 patients had follicular carcinoma. An excellent response was observed in 66.7% of patients with TSH level more than 90 &mgr;IU/ml, 72.2% in the group with TSH level of 60–89 &mgr;IU/ml, 48.5% when TSH was 30–59 &mgr;IU/ml and 26.7% when TSH was less than 30 &mgr;IU/ml (P=0.002). Conclusion Higher preablative serum TSH predicts a better rate of ablation in patients with differentiated thyroid cancer treated with 131I after thyroidectomy.

68Ga-PSMA PET/CT Replacing Bone Scan in the Initial Staging of Skeletal Metastasis in Prostate Cancer: A Fait Accompli?

Micro‐Abstract We compared the findings of technetium‐99m–10‐metacyloyloxydecyl dihydrogen phosphate (99mTc‐MDP) bone scintigraphy and 68Ga–prostate‐specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in 113 patients who underwent initial skeletal staging for prostate cancer. 68Ga‐PSMA PET/CT was found to be better than 99mTc‐MDP bone scintigraphy because of ability to additionally detect lytic and bone marrow lesions. 68Ga‐PSMA PET/CT could potentially replace bone scan for initial staging of skeletal metastases. Purpose 68 Ga ligands targeting prostate‐specific membrane antigen (PSMA) are rapidly emerging as a significant step forward in the management of prostate cancer. PSMA is a type II transmembrane protein with high expression in prostate carcinoma cells. We prospectively evaluated the use of 68Ga‐PSMA positron emission tomography/computed tomography (PET/CT) in patients with prostate cancer and compared the results to those for technetium‐99m (99mTc)‐10‐metacyloyloxydecyl dihydrogen phosphate (MDP) bone scintigraphy (BS). Patients and Methods A total 113 patients with biopsy‐proven prostate cancer referred for standard‐of‐care BS were prospectively enrolled onto this study. 68Ga‐PSMA PET/CT was performed after BS. Metastasis diagnosed on each technique was compared against a final diagnosis based on CT, magnetic resonance imaging, skeletal survey, clinical follow‐up, and histologic correlation. Results Ninety‐one bone lesions were interpreted as bone metastases in 25 men undergoing 68Ga‐PSMA PET/CT compared to only 61 lesions in 19 men undergoing 99mTc‐MDP BS. Of the 7 bone scans that missed skeletal metastases, 54% of these missed lesions were due to either marrow or lytic skeletal metastases. The median standardized uptake value in all malignant bone lesions was 13.84. 68Ga‐PSMA PET/CT showed significantly higher sensitivity and accuracy than BS (96.2% vs. 73.1%, and 99.1% vs. 84.1%) for the detection of skeletal lesions. For extraskeletal lesions, 68Ga‐PSMA PET/CT showed an additional 96 unexpected lesions with a median standardized uptake value of 17.6. Conclusion 68 Ga‐PSMA PET/CT is superior to and can potentially replace bone scan in the evaluation for skeletal metastases in the clinical and trial setting because of its ability to detect lytic and bone marrow metastases.

Burkitt lymphoma and cavernous sinus syndrome with breast uptake on 18F-FDG-PET/CT : a case report

Rationale: Burkitt lymphoma (BL) is a type of non-Hodgkin lymphoma that arises in the B-cells. Cavernous sinus involvement is rare, especially in adults. Here we report an unusual case of a 30-year-old HIV-positive woman with BL and cavernous sinus syndrome who also had intense bilateral breast uptake, related to menstrual cycle. Fluorine-18 2-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been found to be useful in the management of BL. Patient concerns: A 30-year old female patient presented with a history of diplopia and headache. Diagnoses: Magnetic resonance imaging revealed a large cavernous sinus mass. A bone marrow biopsy was done and demonstrated extensive marrow infiltration by Burkitt lymphoma. Further investigation detected the Epstein–Barr virus in her cerebrospinal fluid using qualitative polymerase chain reaction. 18F-FDG PET/CT imaging done revealed a hypermetabolic cavernous sinus mass, conglomerates of enlarged pelvic and para-aortic lymph nodes as well as diffuse bone marrow uptake. Intense bilateral breast uptake was noted coinciding with the start of menses. Interventions: She was started on chemotherapy with adjuvant radiotherapy. Outcomes: After her first cycle of chemotherapy, repeat 18F-FDG PET/CT imaging revealed a marked reduction in the metabolic activity and size of the cavernous sinus mass and conglomerates of lymph nodes. The bone marrow activity was still visualized but less intense compared to the staging PET/CT. Lessons: A cavernous sinus mass will rarely be the primary lesion in Burkitts Lymphoma. Our case demonstrates the role of 18F-FDG PET/CT in the assessment of such cases to detect other primary areas of disease involvement. It is useful in accurate initial staging and monitoring of treatment response in patients with Burkitts Lymphoma.

Salivary Gland Activity Obscures Mandibular Metastasis of Prostate Carcinoma on 68Ga–Prostate-Specific Membrane Antigen PET

We report a case of a 65-year-old man with prostate cancer; his treatment history included radical prostatectomy followed by radiation therapy and subsequent androgen deprivation therapy for more than 5 years. He currently presented with a history of rising prostate-specific antigen and complained of jaw aches. Ga-prostate-specific membrane antigen PET/CT study performed for suspected biochemical recurrence demonstrated vertebral lesions and lesion in his jaw. Subsequent biopsy of jaw lesion demonstrated prostate cancer metastases.

I-123 uptake by intrathoracic stomach.

A 40-year-old man who had a total thyroidectomy 3 years earlier for follicular carcinoma of the thyroid received 100 mCi 1-131 for ablation. Follow-up 1-123 total-body scan showed successful thyroid gland ablation, but also showed persistent stomach activity in the esophageal bed. The patient had resection of esophageal cancer and the stomach was reconstructed in the esophageal bed 7 years prior to the diagnosis of follicular carcinoma. These findings demonstrate well-documented physiologic uptake in the gastric mucosa, which can lead to misinterpretations.