A Comprehensive Analysis of Volumetric 68Ga-PSMA PET/CT Parameters, Clinical and Histopathologic Features: Evaluation of the Predictive Role.

Objectives: To evaluate the relationships between volumetric 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) parameters, Gleason score (GS), prostate-specific antigen (PSA) levels, histopathological data, and metastatic status in newly diagnosed prostate cancer (PCa) patients and to assess the predictive factors for progression despite treatment. Methods: A total of 78 newly diagnosed patients with PCa who had 68Ga-PSMA PET/CT scans were included. Clinical parameters, histopathological data, and metastatic status were documented, and volumetric parameters of primary prostate lesions were measured. All obtained data were compared statistically. Results: Primary prostate tumor maximum standardized uptake value (SUVmax) and GS were significantly related to serum PSA levels (p<0.05). PSA levels and SUVmax values were significantly higher in patients with lymph node metastases than in those without. GS was found to be significantly increased in metastatic patients. PSMA-derived tumor volume (PSMA-TV) and total lesion PSMA of the primary lesion had a significant relationship with PSA value, GS, and regional lymph node metastases. Receiver operating characteristic analysis, conducted in patients with metastatic and localized disease, identified the cutoff value for SUVmax as 10.85. According to the results of the logistic regression analysis, PSMA-TV was found to be a predictive factor for progression despite treatment. Conclusion: 68Ga-PSMA PET/CT remains an invaluable imaging modality that should be considered first in PCa staging because of its superior compatibility with clinical and histopathologic data. The importance of this method goes beyond diagnostic accuracy; it also extends into the predictive domain, where the PSMA-TV value of primary prostate lesions is a potential predictor of treatment efficacy. This information is valuable for personalizing patient treatment, improving prognostic accuracy, and predicting clinical outcomes.

EFFECTIVE HALF-LIFE, EXCRETION AND RADIATION EXPOSURE OF 177LU-PSMA.

The study aims to evaluate the radiation safety conditions by detecting the patient's urine excretion rate, calculating the effective half-life, and determining the retention of 177Lu-PSMA in the body. Urine samples of patients were collected for 24 hours (6, 12, 18, and 24 hours) following the infusion, excretion rate and retention of 177Lu-PSMA in the body of patients were calculated. The measurements of dose rate were performed. Effective half-life calculated from dose rate measurements was found as 18.5 ± 11 h within the first 24 h and 48.1 ± 22.8 h between 24 and 72 h. Excreted activity in urine was found as 33.8 ± 20.7, 40.4 ± 20.3, 46.1 ± 22.4, and 53.3 ± 21.5% of total doses at 6, 12, 18, and 24 h after administration, respectively. External dose rates for 4 h and 24 h were 24.51 µSv/h, 16.14 µSv/h, respectively. Our results showed that 177Lu-PSMA treatment was suitable for outpatient treatment in terms of radiation safety.

Inguinoscrotal Bladder Hernia Mimicking Testicle Tumor.

Bladder hernias usually begin asymptomatically and are discovered incidentally at the time of discovery. Preoperative diagnosis of bladder hernias is important to reduce the risk of bladder injury during surgery. Although F-18 FDG PET/CT is applied for oncological purposes, benign conditions should also be taken into account when evaluating the implants. In this article, a case of bladder hernia, which can be confused with pathological cancer involvement, with the diagnosis of F-18 FDG PET/CT performed in a 73-year-old male patient with renal cell carcinoma is presented.

Contribution of Open Mouth Technique in 18F-FDG PET/CT Imaging in Patients with Malignant Lip Neoplasm.

Objectives: 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) plays an important role in evaluating head and neck cancers. However, localization and size evaluation in this region can be rough due to the multitude of the anatomic structures and physiologic uptakes. The aim of this study was to evaluate malignant lip lesions with the contribution of open mouth (OM) imaging technique at PET/CT. Methods: Fifty-six patients with malignant lip neoplasm underwent 18F-FDG PET/CT imaging. Each patient was imaged twice as whole-body PET/CT with routine closed mouth (CM) position; and OM head and neck image, standardized with a special device. Lesion maximum standard uptake value (SUVmax), localization, size, and involvement of lymph nodes were evaluated. Results: Lesion localization was correctly detected in 100% of the OM images. Lesion size in PET/CT was compared with clinical, radiological (magnetic resonance imaging and CT) and/or histopathological results and the size measurement was coherent at 47.1% and 95.6% for CM and OM images, respectively. It was observed that OM acquisition did not contribute additionally in detecting regional lymph node metastasis. Forty-one PET/CT scans with CT artifacts due to dental amalgams were evaluated and 46.3% dimensional and 53.7% localization errors were detected in the CM position. There was no statistically significant difference between OM and CM SUVmax (p>0.05). Conclusion: We concluded that additional OM head and neck imaging is useful and necessary to accurately determine the localization and size of the tumor, thus enhancing the value of PET/CT in staging, treatment response assessment, and restaging of patients with malignant lip cancer with or without dental amalgam.

Unexpected Metastatic Localizations of Prostate Cancer Determined by 68Ga PSMA PET/CT: Series of Four Cases.

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.

Samarium-153 therapy for prostate cancer: the evaluation of urine activity, staff exposure and dose rate from patients.

The aim of this study was to determine the excretion of Samarium-153-ethylenediaminetetramethylphosphonic acid ((153)Sm-EDTMP) in urine and to calculate the dose rate of its retention in the body as a function of time and the dose received by the skin of laboratory staff's finger. Urine samples were collected from 11 patients after intravenous injection of (153)Sm-EDTMP. The measurements of dose rate were performed. Thermoluminescent dosemeters were used for absorbed dose measurements. Effective half-lives that were calculated from urine sample measurements were found as 7.1±3 h within the first 24 h. Whole body dose rates before collecting urine of patients were 60.0 ± 15.7 µSv h(-1) for within 1 h following (153)Sm-EDTMP administration. The highest finger radiation dose is to the right-hand thumb (3.8 ± 2 mGy). The results of the study imply that patients who recieved (153)Sm-EDTMP therapy should be kept a minumum of 8 h in an isolated room at hospital and that one staff should give therapy at most two patients per week.

Gastric emptying of solids and its relationship with microalbuminuria in children and adolescents with type 1 diabetes mellitus.

BACKGROUND: The aims of the present study were to determine the frequency of delayed gastric emptying in children and adolescents with type 1 diabetes mellitus (T1DM) and to investigate the relationship between gastric emptying rate and other contributing factors (e.g. serum HbA1c, duration of diabetes and microalbuminuria) in these patients. METHODS: This was a clinical trial evaluating the rate of gastric emptying of solid meals in 33 children and adolescents with T1DM and in 26 healthy peers using a radionuclide method. Three consecutive overnight urine collections were used to calculate the albumin excretion rate. RESULTS: There was no significant difference in the gastric half-emptying time (GE t½ ) between patients and controls (151.7 ± 154.5 vs 109.8 ± 60.5 min, respectively; P=0.885) or the frequency of delayed gastric emptying (36.4% vs 30.8%, respectively; P=0.433). There was a moderately positive correlation between GE t½ and the duration of diabetes (r=0.380; P=0.029). There was no correlation between GE t½ and microalbumin levels in T1DM patients. In these patients, the body mass index standard deviation scores were significantly lower than in patients with normal gastric emptying (-0.13 ± 0.87 vs 0.7 ± 1.23, respectively; P=0.044). CONCLUSION: Progression of delayed gastric emptying is more likely to be related to a longer duration of diabetes than glycemic control in children and adolescents with T1DM. Patients with delayed gastric emptying are thinner compared with patients with a normal rate of gastric emptying; they may also be asymptomatic.

The evaluation of urine activity and external dose rate from patients receiving radioiodine therapy for thyroid cancer.

The aim of this study was to determine the external dose rate of iodine retention as a function of time in the bodies of thyroid cancer patients during their isolation period in the hospital. Urine samples were collected at 6th, 12th, 18th, 24th h and 2nd, 3rd, 4th, 5th d from 83 patients after oral administration of (131)I and counted. The external dose rates were also simultaneously determined at the same time points. Then, it was expressed as retained radioiodine body activity versus dose rate. Effective half life calculated from urine sample measurements was found as 18.4±1.8 h within the first 24 h and 64±2.7 h between 48 and 120 h. According to this results, the external dose rate (<20 µSv h(-1)), which patients could be discharged, was achieved after 48 h for 3700 and 5550 MBq, and after 72 h for 7400 MBq of (131)I treatments.

Technetium-99m-hexamethylpropylene amine oxime lung scintigraphy findings in patients with Behçet's disease.

AIM: Behçet's disease (BD) is a multisystem disorder that is characterized by vasculitis, and consists of a triad of recurrent ulcers of the oral and genital mucosa with relapsing uveitis. The prevalence of pulmonary involvement varies in the range of 1-10% in various studies, and its complications are severe and life threatening. To objectively assess the degree of pulmonary vascular endothelial damage in BD, the lung uptake, and the clearance rate of technetium-99m-hexamethylpropylene amine oxime (Tc-99m-HMPAO) were determined. METHODS: Twenty-three nonsmoking patients with BD (10 female, 13 male) and 11 (six female, five male) healthy nonsmoking controls underwent Tc-99m-HMPAO lung scanning, pulmonary function tests (PFT), chest radiograph examination, contrast-enhanced spiral chest computed tomography scanning, and high-resolution computed tomography examinations. Immediately after the bolus injection of 740 MBq of Tc-99m-HMPAO posterior sequential images were obtained at 1-s intervals for 150 s and subsequent images were obtained at one frame per minute (min) over a 10-min period, using a double-headed gamma camera equipped with a low-energy all-purpose parallel hole collimator. Dynamic images were used to calculate the Tc-99m-HMPAO lung clearance rate (T1/2). Simultaneously, a static anterior image, including a large part of the liver, was obtained of 5-min duration at 10 min after the injection. Regular regions of interests were drawn over the midportion of the right lung and the highest activity area of the liver parenchyma was selected and lung/liver (L/Li) uptake ratios were calculated to represent the degree of pulmonary vascular endothelial damage. RESULTS: Chest radiograph, high-resolution computed tomography, and computed tomography findings in patients with BD were nonspecific for BD. There was also a statistically significant difference between patients with BD (30.26 ± 10.55 s) and normal controls (19.53 ± 6.24 s) on their T1/2 values (P = 0.0004). The results show that the L/Li ratios on the Tc-99m-HMPAO lung scan were significantly higher in patients with BD (0.60 ± 0.19) than those in normal controls (0.39 ± 0.07) (P = 0.0021). Using a cutoff value of 0.50, 15 of 23 (65%) patients with BD had increased L/Li ratios. No correlation was found between the mean T1/2 values of Tc-99m-HMPAO clearance and the PFT in patients with BD. The L/Li ratios were not correlated with PFT in patients with BD. CONCLUSION: The degree of pulmonary vascular endothelial damage was represented as increased L/Li ratios and decreased lung clearance rate measured on the Tc-99m-HMPAO lung scan in patients with BD. Our results indicated that determining the T1/2 values and the L/Li ratios on Tc-99m-HMPAO lung imaging should be an objective method to assess subclinical pulmonary damage even in the early stages of BD in the patients.

Assessment of alveolar epithelial permeability with Tc-99m DTPA aerosol scintigraphy in patients with Sjogren syndrome.

Sjögren's syndrome (SjS) is a systemic autoimmune disease that mainly affects the exocrine glands and usually presents as persistent dryness of the mouth and eyes. Lung disease in SjS has been reported to occur early following clinical presentation of the disease. In this study, technetium-99m diethylene triamine penta-acetic acid (Tc-99m DTPA) aerosol inhalation scintigraphy was used to assess the pulmonary membrane permeability in patients with primary SjS. A total of 18 patients with primary SjS and 13 healthy controls were investigated. Clinical evaluation, chest X-ray examination, pulmonary function tests, Tc-99m DTPA aerosol scintigraphy were performed in all the cases. The presence of respiratory symptoms (dyspnea and cough), duration of sicca symptoms were recorded. The clearance half time of Tc-99m DTPA radioaerosols in patients with SjS (20.49 +/- 2.56 min) was faster when compared to normal controls (42.32 +/- 13.28 min) (P = 0.000) which means that there is a significant increase in lung permeability in patients with SjS compared to the controls. There is also a significant difference between PI of patients with SjS (0.34 +/- 0.09) and that of controls (0.42 +/- 0.07) (P = 0.012). According to the results of our preliminary study, one can detect pulmonary involvement by Tc-99m DTPA aerosol inhalation scintigraphy in patients with primary SjS.

Clinical significance of lung perfusion defects in children with post-infectious bronchiolitis obliterans.

Clinical significance of segmental lung perfusion defects in children with bronchiolitis obliterans (BO), have not been reported before. The aim of this study was to evaluate clinical significance of lung perfusion defects in children with BO and to reveal its impact on follow up. The study included 38 children aged 9 to 60 months (17.8 + or - 13.4 months) with BO. Diagnosis was based on persistent respiratory findings beyond six weeks and oligemic-mosaic pattern in lung high resolution computerized tomography. Chest X-ray, 24 hour esophageal pH monitoring, sweat chloride test, immunoglobulin levels and respiratory viral screening were carried out in all. Lung perfusion scintigraphy was carried out at least three months after the first clinical sign of BO. Perfusion defects were scored. Scintigraphy demonstrated perfusion defects in 24 (63.2%) patients but was normal in 14 (36.8%). Number of segments having perfusion defects was 2.9 + or - 2.6. Mean number of exacerbations and days of hospitalization during the first year of follow up were 4.7 + or - 4.4 and 26.9 + or - 29.8 respectively. It was detected that number of perfusion defects correlated significantly with the number of exacerbations and duration of hospitalization (r= 0.66 and p= 0.00). In conclusion, number and extent of segments with perfusion defects in lungs of children with BO are correlated with clinical severity. Therefore, evaluation of lung perfusion status may aid in clinical determination of disease severity and its follow-up.

Effects of 99mTc-MIBI and 99mTc-MDP administration on dual-energy X-ray absorptiometry bone mineral density measurements.

OBJECTIVE: Nuclear medicine procedures are often performed in close-time proximity to bone densitometry studies. The purpose of this study was to determine the effects of Tc-hexakis-2-methoxyisobutyl isonitrile (MIBI) and Tc-methylene diphosphonate (MDP) on the accuracy of bone mineral density (BMD) measurements performed using dual-energy X-ray density. METHODS: The effect of a diagnostic dose of Tc-MIBI on BMD estimations in the lumbar spine and the left total hip was assessed in 30 patients (19 female, 11 male; mean age: 55.5+/-10.5 years) by using a Lunar DPX-NT scanner. Thirty patients, admitted to the nuclear medicine department for bone scintigraphy (15 female, 15 male; mean age: 56+/-15.92 years), were included into the study. Each patient underwent dual-energy X-ray density assessment for which a Lunar DPX-NT scanner was used before and 2 h after intravenous injection of Tc-MDP (925 MBq) and Tc-MIBI (1110 MBq). BMD measurements were calculated from lumbar spine (including L2-4) and left hip (including femoral neck, trochanter, and total hip). For statistical analysis, the Wilcoxon test was used and a P value of less than 0.05 was accepted as statistically significant. RESULTS: According to Wilcoxon's statistical test, we found extremely significant changes on the measured BMD, T-score, before and 2 h after the injection of Tc-MIBI for lumbar spine and left hip in 30 patients. We found statistically significant decrement on measured BMD from lumbar spine and trochanter before and 2 h after the injection of Tc-MDP. Although MDP BMD values in femoral neck and total hip were decreased after the injection of Tc-99m, they did not reach a statistically significant value. The comparison of pre-T-score and post-T-score values showed a statistically significant decrease after the injection for only L2-4 lumbar spine (P = 0.002), but left hip of pre-T-score and post-T-score values did not reach a statistically significant value. CONCLUSION: In this study, it was determined that measured BMD values are decreased in lumbar spine for all patients. The magnitude of the effect is dependent on the location of the activity. We assume that some radioactivity from Tc is counted by the densitometer's detector, thus resulting in a decrease in the measured BMD. Scintigraphy and bone densitometry should be performed on different days to avoid artifactual reduction in BMD measurements.

Assessment of alveolar epithelial permeability in Behçet's disease with 99mTc-DTPA aerosol scintigraphy.

OBJECTIVE: Behçet's disease (BD) is a multisystem disorder characterized by vasculitis, and consists of a triad of recurrent ulcers of the oral and genital mucosa with relapsing uveitis. The prevalance of pulmonary involvement varies in the range of 1-10% in various studies and its complications are severe and life threatening. In this study, we investigated the changes of pulmonary epithelial permeability of patients with BD using technetium-99m diethylene triamine penta-acetic acid ((99m)Tc-DTPA) aerosol scintigraphy, so as to begin the therapy regimen as soon as possible. METHODS: Twenty-one nonsmoking patients with BD (8 women, 13 men; mean age 38.67 +/- 8.86 years) and 15 healthy volunteer nonsmoking controls (8 women, 7 men; mean age 50.87 +/- 12.45 years) underwent (99m)Tc-DTPA aerosol inhalation scintigraphy and pulmonary function tests (PFTs). Subjects inhaled 1480 MBq of (99m)Tc-DTPA for 4 min in the supine position. Scintigraphic data were recorded dynamically (1 frame/min) in the posterior projection on a 64 x 64 matrix for a 30-min period using a double-headed gamma camera (Infinia, GE, Tirat Hacarmel, Israel) equipped with a low-energy all-purpose parallel hole collimator. Half time of (99m)Tc-DTPA clearance (T (1/2)) was calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was also calculated by dividing the peripheral total counts by the sum of the peripheral and central total counts on the first minute image, in order to quantify the distribution of the inhaled aerosol. RESULTS: The clearance half time of (99m)Tc-DTPA radioaerosols in the BD patients (24.81 +/- 6.22 min) was faster than in the normal control group (46.53 +/- 22.41 min) (P = 0.004). There was also a significant difference between PI of the patients with BD (0.15 +/- 0.03) and that of the controls (0.21 +/- 0.06) (P = 0.002). No correlation was found between the mean T (1/2) values of (99m)Tc-DTPA clearance or the spirometric measurements in the BD patients. Penetration indices were not correlated with PFT in the BD patients. CONCLUSIONS: Lung epithelial permeability of the patients with BD was significantly higher than that of the normal subjects. The results of this study demonstrated that the assessment of lung epithelial permeability using (99m)Tc-DTPA aerosol scintigraphy could predict the presence of lung involvement in the early stages of BD.

Comparison of brain perfusion SPECT and MRI findings in children with neuronal ceroid-lipofuscinosis and in their families.

PURPOSE: Neuronal ceroid-lipofuscinoses (NCL) are among the progressive encephalopathies of childhood that are inherited in an autosomal recessive manner. In this study we specifically aimed to investigate any white-matter changes in the carriers (parents) and the healthy siblings of individuals with neuronal ceroid lipofuscinosis disease and whether we may be able to predict the occurrence of any neurological symptoms in healthy children in the future thus enabling early management. MATERIALS AND METHODS: Since the NCLs are genetically determined diseases, we investigated fifteen individuals in three families that had diseased children of the juvenile type, with brain perfusion SPECT and MRI. Brain perfusion SPECT was performed after administering 222-555 MBq (6-15 mCi) Tc-99m HMPAO intravenously in a dimmed and quiet room. Imaging was performed at least one hour after injection, with a three headed gamma camera equipped with high resolution collimators. A Metz filter (FWHM: 11 mm) was used for processing. Cranial MRI was performed with an imager operating at 1.5 Tesla. Spin-echo T1- and T2-weighted and FLAIR slices were obtained for each individual. RESULTS: In all of the five diseased children we observed pathologic findings both on MRI and Tc-99m HMPAO SPECT. The findings on MRI were mainly features of cerebral and cerebellar atrophy and the observations on Tc-99m HMPAO SPECT were regional perfusion abnormalities. We observed some structural abnormalities on MRI in four of the parents and two of the four healthy siblings. We also noted perfusion abnormalities on Tc-99m HMPAO SPECT in two of the parents and two of the healthy siblings. CONCLUSION: Because the disease is inherited in an autosomal recessive manner, the parents and the healthy siblings were not supposed to exhibit any demonstrable brain lesions, but the brain perfusion SPECT and MRI examinations clearly revealed multiple lesions in some of the parents and healthy siblings. Detailed neurological examinations of these individuals were normal except for one apparently healthy sibling (EY). Follow-up imaging of these families is being undertaken and further studies are essential in understanding the pathogenesis and genetics of neuronal ceroid-lipofuscinoses.