Iranian Journal of Nuclear Medicine
Volume:33 Issue: 1, Winter-Spring 2025

Thyroid cancer is the most common endocrine malignancy. This often involves the middle-aged and active population, typically younger compared to those with other types of cancers. Some people with thyroid cancer may develop secondary malignancy. The reason for this is not well understood. This study was designed to evaluate the prevalence of second primary cancers in patients with differentiated thyroid cancer and its probable relationship with the severity of treatment and staging of the primary tumor. Among 2638 patients who underwent thyroidectomy between 1996 and 2018, we checked cases who suffered from non-thyroidal second primary cancers before, during, or after the diagnosis of thyroid cancer. Forty-nine patients met the criteria and were included in the study. The information was gathered from the medical records and supplemented by direct communication with the patients. The Data was then analyzed using appropriate statistical test with   SPSS version 22, considering a P-value of 0.05 was considered as significant. Out of the 2638 checked records reviewed, 49 patients (1.85%) were found to have second primary cancers with 75.5% being female. One patient had two concurrent second primary cancers, while the remaining 48 patients had a single second primary cancer. Most of the thyroid cancers were papillary (89.8%, 44 cases), with the others remaining cases being follicular type. Stage 2, according to the 8th AJCC staging system, was the most common (50%), followed by stage 1 (36.8%) among the primary staging categories. Breast cancer was the most prevalent (17 cases), followed by hematologic malignancies (8 cases) and GI tract cancers (8 cases).  The findings revealed a significant increase in the number of breast cancers in patients with the differentiated thyroid cancer (DTC), which was not observed for other malignancies.

99mTc[Tc]-MIBI breast scintimammography offers a noninvasive method for assessing breast cancer biology. Studies suggest a potential prognostic value in washout analysis, as accelerated washout correlates with high histologic grade. The study examines whether the washout rate of 99mTc[Tc]-MIBI, a marker of mitochondrial dysfunction, correlates with the ki-67 index, a reliable predictive tool for breast cancer that estimates cellular proliferation.

In this study, 30 cases of breast cancer who were intact, without previous breast operation, prior chemotherapy, and previous radiotherapy, had prone scintimammagraphy. The diagnosis was approved by biopsy. The standard 20 mCi 99mTc[Tc]-MIBI was applied to all patients, and after 15 min and 60 min of injection, two imaging series were taken at each time. After different methods of calculation of washout, the washout percentage has been correlated with the Ki-67 index in the patients.

All breast cancers showed significant tracer uptake at 15 minutes, mostly correlated with tumor angiogenesis. Imaging at 60 minutes revealed decreased activity, indicating a positive correlation between higher 99mTc[Tc]-MIBI washout and higher breast cancer grade as indicated by the Ki-67 index.

The significant association between increased 99mTc[Tc]-MIBI washout and increased cancer grade indicates that washout analysis may have potential prognostic utility before or during surgical treatment. Additionally, there is a suggestion of increased tumor grade correlating with increased mitochondrial dysfunction. While further prospective validation is necessary, this pilot study demonstrates that washout kinetics could serve as a noninvasive imaging biomarker for breast cancer grade to supplement clinical management algorithms.

Differential renal function calculation plays an important role in surgical decisions in hydronephrotic kidneys, which may show false-positive or false-negative results owing to the asymmetrical renal area in hydronephrotic kidneys. The disparity between the visual and quantitative estimations of renal function can complicate decision making for renal interventions at the optimal time. This study was designed to evaluate whether correcting the differential renal function (DRF) estimation according to kidney unit area can be a more valuable predictor of the functional status of a hydronephrotic kidney than the classical geometric mean method. Tc-99m Dimercaptosuccinic acid ([99mTc]Tc-DMSA) scans and ultrasonography finding of 524 patients with unilateral hydronephrosis due to urinary tract obstruction were reviewed. Differential renal function estimated by both classical geometric mean and unit area corrected method were compared. The correlations of the differential renal function values with the visual classification and the hydronephrosis grades were assessed. The mean Differential renal function by the classical geometric mean and the unit area corrected method of the hydronephrotic kidneys was 41.2%±12.3 and 36.6%±9.9 respectively, with mean difference of 4.6±7.7% (p<0.001). With increasing hydronephrosis grade, differential renal function decreased significantly by the unit area corrected method (p<0.001). Our results suggest that differential renal function estimation by the unit area corrected method is more reliable than by the classical geometric mean method in unilateral enlarged hydronephrotic kidney to avoid misinterpretation due to over-estimation of renal function.

[68Ga]Ga-PSMA PET/CT has gained acceptance for localizing local and distant metastases; However, urinary activity remains a confounding factor in interpreting local metastases. The aim of this study was to evaluate the diagnostic value of two-phase protocol (i.e., early and regular imaging, TPP) in comparison with delayed optimized protocol (i.e., combined regular and delayed post hydration and diuresis images, DOP) to detect locoregional prostatic metastases. Forty-one prostate cancer patients referred for staging (n = 12) or the evaluation of rise in PSA level in prostate cancer (n = 29) were prospectively assessed. In this study, each patient received an early 5-10 min image from pelvic region for two bed position, regular (RP) (60 min) and finally delayed static images. The scan findings were characterized as positive, negative or equivocal. The diagnostic significance of TPP was compared with DOP for prostatic, periprostatic, locoregional lymph nodes and pelvic bone involvement. The diagnostic agreement between DOP and TPP for prostate/prostate bed lesions was comparable with the agreement of DOP and RP (Kappa: 0.78, p < 0.001) vs. (Kappa: 0.8, p value < 0.001). TPP in comparison with RP, had superior sensitivity for prostate/prostate bed lesions (95% vs. 80%). The sensitivity for lymph node metastases, extraprostatic extension and osteometastases was identical between the two protocols. TPP has the potential to replace DOP for the evaluation of prostate/prostate bed lesions; however, there remains instances where delayed imaging is helpful in characterizing the anatomic abnormality especially in the lymph node region.

Technetium-99m-pyrophosphate scintigraphy (TPS) is a highly effective method for diagnosing transthyretin cardiac amyloidosis (ATTR-CA). It may eliminate the need for endomyocardial biopsy. However, the detection of radioactivity in the blood pool (BP) during these scans can make it difficult to interpret planar images. This often leads to the necessity for longer and repeated scanning sessions. We conducted a prospective study involving unique patients who underwent TPS. The initial group of 58 patients used a pyrophosphate (PYP) kit labeled with 30 mCi (PYP-30) of radioactivity, while the subsequent group had a kit labeled with 90 mCi (PYP-90), although the administrated dose remained constant. This study aimed to assess how varying radioactivity levels in the kits affected BP activity visualization. Univariable analysis showed creatinine level of the patients and added radioactivity amount in the PYP kits affected BP activity (p<0.05), while gender, age, and BMI did not (p>0.05). Multivariable analysis confirmed creatinine (OR<0.001) and added radioactivity (OR=0.005) significantly influenced BP visualization. Patients with creatinine<1.5 showed a significant difference in BP activity between two groups (PYP-30 and PYP-90), but those with creatinine ≥1.5 did not. These findings emphasize the significance of considering the levels of radioactivity in PYP kits, which may be linked to the concentration of free Sn²⁺ in the prepared kit, as well as the patient’s kidney function. These factors are essential for optimizing imaging quality and improving diagnostic accuracy in cases of cardiac amyloidosis.

Thyroid oncocytic carcinoma, also known as Hürthle cell carcinoma (HCC), is a rare subtype of thyroid cancer with unique characteristics. Radioiodine therapy, while less effective for HCC due to poor radioiodine accumulation in tumor, has shown improved survival rates for tumors larger than 2 cm. Adjuvant radioiodine therapy is recommended in certain cases, particularly for older patients with a worse prognosis. This study reviewed data from 18 HCC cases compared to the overall patient population (OPP) at our center between 2019 and 2022. The mean age at diagnosis was higher for HCC patients compared to OPP, with varying responses to therapy observed. Assessment of response to therapy after one year revealed 26.7%, 20%, 20%, and 33.3% of HCC patients with excellent, indeterminate, biochemical incomplete, and structural incomplete responses, which were 41.5%, 24.7%, 13%, and 20.7% in OPP, respectively. The Kaplan curve of patient survival showed an average of 100±13.5 months. Approximately 44% of HCC patients showed excellent survival outcomes after radioiodine therapy, highlighting its importance as a treatment option for HCC. Further research is needed to optimize treatment choices and improve patient outcomes in this less common subtype of thyroid cancer.

Neurofibromatosis type 1 (NF1) is a prevalent inherited condition, having a risk for malignant conversion to malignant peripheral nerve sheath tumor (MPNST). Our study objective was to assess the effectiveness of [18F]FDG PET/CT and Magnetic Resonance Imaging (MR) in identifying early transformation in pediatric patients, given the limited data available in existing literature. In this study children with suspected or confirmed NF1 who underwent [18F]FDG between January 2007 and April 2024 were included in a retrospective cross-sectional analysis. Exclusion criteria was follow-up periods shorter than one-year post [18F]FDG results. The study included 13 patients (6 females, 7 males), with a median age of 11 years, and a total of 16 lesions. Only two lesions were confirmed by biopsy to have undergone malignant transformation into a MPNST. Although the findings varied, [18F]FDG imaging was able to anticipate the malignant transformation only in one of these two cases. Due to the limited sample size, definitive conclusions could not be provided. We were unable to propose a specific SUVmax cutoff to predict the malignant transformation of neurofibromas in children with NF1  disease.

Pelvic actinomycosis, a chronic and invasive condition caused by Actinomyces spp., often mimics malignancies, creating diagnostic challenges. This report details the case of a hysterectomized woman presenting with vaginal bleeding, intense pelvic pain, constipation, and weight loss. Initial assessments suggested sarcoma due to a firm, fixed mass in the right pelvis with vaginal infiltration. Imaging techniques, such as contrast-enhanced Computerized Tomography (CECT) of the abdomen and pelvis, and [18F]FDG Positron Emission Tomography Computed Tomography (PET/CT scan), confirmed a solid cystic pelvic mass infiltrating surrounding structures. Cystoscopy showed bladder mucosa infiltration; however, biopsies were inconclusive for malignancy but indicated actinomycosis. Treatment with oral Penicillin G significantly alleviated pain, restored bowel function, and led to weight gain, along with radiological improvements.

Superior Vena Cava Syndrome (SVC syndrome) due to a retrosternal goiter is exceptionally rare, with only a handful of documented cases in medical literature. The utilization of radionuclide venography is a valuable, noninvasive procedure that plays a crucial role in the comprehensive assessment of these rare occurrences. We present here a case of 55-year-old male patient referred to nuclear medicine department for evaluation of neck swelling. He had neck swelling for a past 06 years accompanied by dyspnea on lying down and had visibly dilated veins in the neck and anterior chest wall. Based on sign and symptoms of the patient, superior vena cava syndrome was provisional diagnosis and radionuclide venography with thyroid scan (and SPECT/CT) were performed. Scintigraphic findings favored SVC syndrome secondary to retrosternal goiter. Patient was referred to surgical department where subtotal thyroidectomy was performed. Histopathology showed benign thyroid nodular disease. The patient is now clinically stable, on thyroxine and his symptoms have resolved. Radionuclide venography stands out as a non-invasive and safe diagnostic tool that not only aids in the initial identification of SVC syndrome but also provides essential insights into collateral circulation dynamics.

Vascular grafts and endografts infection (VGEI) are considered rare but the most difficult in cardiovascular surgery. Treatment requires complete replacement of the prosthesis. However, in situations where this is technically impossible, the patient is required to take long-term (sometimes-lifelong) antibiotic therapy. Diagnosis and monitoring of treatment success requires the use of clinical data, imaging techniques, and microbiologic tests. One method for specific imaging of septic inflammation is SPECT/CT with [99mTc]Tc-HMPAO-WBC. According to EANM and ESVS guidelines, [99mTc]Tc-HMPAO-WBC SPECT/CT results definitively confirm or reject the infection. However, the control of treatment efficacy is undiscussed. This report describes a case of severe infection of the prosthesis and paraprosthetic space by Morganella morganii one year after frozen elephant trunk (FET) surgery. We applied a multidisciplinary approach to patient management and monitoring of treatment success in particular using [99mTc]Tc-HMPAO-WBC SPECT/CT.

A 71-year-old man with prostate adenocarcinoma underwent [99mTc]Tc-MDP whole body and SPECT/CT scans for primary staging, which revealed unexpected vertical linear uptake in the intercostal spaces. Subsequent evaluation with [99mTc]Tc-PSMA scintigraphy revealed no uptake in these areas, and physical examination revealed no tenderness or cutaneous changes. Further investigation led to the diagnosis of bridging rib, a rare congenital anomaly occurring in less than 0.5% of the population, characterized by developmental fusion between two or more ribs. This case underscores the significance of considering rare anatomical variants in the interpretation of imaging studies, as it can affect the accuracy of diagnoses, and provides a review of the differential diagnoses that may be mistaken for one another when interpreting bone agent uptake in the ribs.