Role of (18)F-DOPA PET/CT and (131)I-MIBG planar scintigraphy in evaluating patients with pheochromocytoma.

OBJECTIVE: The aim of this retrospective study was to evaluate role of (18)F-DOPA PET/CT and (131)I-MIBG planar scintigraphy in patients with pheochromocytoma. METHODS: The patients with diagnosis of pheochromocytoma based on radiological and biochemical markers were retrospectively selected for the study. These patients had undergone both (131)I-MIBG scintigraphy and (18)F-DOPA PET/CT. The imaging findings were compared to patient histopathology reports, biochemical markers and clinical follow up whenever available to establish the diagnosis. RESULTS: (131)I-MIBG showed a sensitivity of 68% and specificity of 100%. (18)F-DOPA PET/CT showed a sensitivity of 82% and specificity of 100%. (18)F-DOPA was better at localizing and finding more no of lesions as compared to (131)I-MIBG scintigraphy. (18)F-DOPA also is a better study in evaluation of paragangliomas. CONCLUSIONS: (18)F-DOPA PET/CT seems to be a better modality in comparison to (131)I-MIBG scintigraphy in the evaluation of pheochromocytoma/paraganglioma. At this point both these tracers seem to have mutually additive role in these patients and essential investigations with diagnosis and follow-up of this disease.

The role of 18F-fluoride PET-CT in the detection of bone metastases in patients with breast, lung and prostate carcinoma: a comparison with FDG PET/CT and 99mTc-MDP bone scan.

OBJECTIVES: We aimed to compare the role of (18)F-fluoride PET/CT, FDG PET/CT and (99m)Tc-MDP bone scans in the detection of bone metastases in patients with lung, breast and prostate carcinoma. METHODS: This was a prospective study including patients for staging (S) and restaging (R). Seventy-two patients (23S, 49R) with infiltrating ductal breast carcinoma, 49 patients (25S, 24R) with prostate adenocarcinoma and 30 patients (17S, 13R) with non-small-cell lung carcinoma (NSCLC), without known bone metastases but with high risk/clinical suspicion for the same, underwent a (99m)Tc-MDP bone scan, FDG PET/CT and (18)F-fluoride PET/CT within 2 weeks. All scans were reviewed by two experienced nuclear medicine physicians, and the findings were correlated with MRI/thin-slice CT/skeletal survey. Histological verification was done wherever feasible. RESULTS: Sensitivity and negative predictive value (NPV) of (18)F-fluoride PET/CT was 100 % in all three malignancies, while that of FDG PET/CT was 79 % and 73 % in NSCLC, 73 % and 80 % in breast cancer and 72 and 65 % in prostate cancer. Specificity and positive predictive value (PPV) of FDG PET/CT were 100 % in NSCLC and prostate and 97 % and 96 % in breast cancer. As compared to the (99m)Tc-MDP bone scan, all parameters were superior for (18)F-fluoride PET/CT in prostate and breast cancer, but sensitivity and NPV were equal in NSCLC. The MDP bone scan had superior sensitivity and NPV compared to FDG PET/CT but had low specificity and PPV. CONCLUSION: To rule out bone metastases in cases where there is a high index of suspicion, (18)F-fluoride PET/CT is the most reliable investigation. (18)F-fluoride PET/CT has the potential to replace the (99m)Tc-MDP bone scan for the detection of bone metastases.

(99m)Tc-DMSA (V) in Evaluation of Osteosarcoma: Comparative Studies with (18)F-FDG PET/CT in Detection of Primary and Malignant Lesions.

To evaluate the role of (99m)Tc-DMSA (V) and [(18)F]FDG PET-CT in management of patients with osteosarcoma, 22 patients were included in our study. All patients underwent both (99m)Tc-DMSA (V) and whole-body [(18)F]FDG PET-CT scans within an interval of 1 week. 555-740 MBq of (99m)Tc-DMSA (V) was injected i.v. the whole-body planar, SPECT images of primary site and chest were performed after 3-4 hours. [(18)F]FDG PET-CT images were obtained 60 minutes after i.v. injection of 370 MBq of F-18 FDG. Both FDG PET-CT (mean SUV(max) = 7.1) and DMSA (V) scans showed abnormal uptake at primary site in all the 22 patients (100% sensitivity for both). Whole-body PET-CT detected metastasis in 11 pts (lung mets in 10 and lung + bone mets in 1 patient). Whole-body planar DMSA (V) and SPECT detected bone metastasis in one patient, lung mets in 7 patients and LN in 1 patient. HRCT of chest confirmed lung mets in 10 patients and inflammatory lesion in one patient. 7 patients positive for mets on DMSA (V) scan had higher uptake in lung lesions as compared to FDG uptake on PET-CT. Three patients who did not show any DMSA uptake had subcentimeter lung nodule. Resuts of both (99m)Tc-DMSA (V) (whole-body planar and SPECT imaging) and [(18)F]FDG PET-CT were comparable in evaluation of primary site lesions and metastatic lesions greater than 1 cm. Though (99m)Tc-DMSA (V) had higher uptake in the lesions as compared to [(18)F]FDG PET-CT, the only advantage [(18)F]FDG PET-CT had was that it could also detect subcentimeter lesions.

Characterization of Re-188-Sn microparticles used for synovitis treatment.

Rhenium-188 labeled tin (Sn) microparticles were developed for pain palliation therapy in the patients suffering from synovitis with acute pain. The rhenium tin microparticles were prepared using stannous chloride and freshly eluted (188)ReO(4)(-) from (188)W/(188)Re generator. The aggregated colloidal particles, packed in a spherical form after boiling for 90-120min were analyzed using electron microscope. The size, surface morphology and stability of microparticles were analyzed by changing temperature and volume conditions. The small colloidal particles clustered and formed spherical microparticles. The 90% of microparticles were in 5-10microm range, after 90min and 120min of boiling. The radiolabeling efficiency was improved to 98% after centrifugation for 10min at 3500rpm. The formulations were stable but the increase in volume had inverse effect on labeling efficiency. No leak was observed from knee area up to 24h with 15-20mCi injection of (188)Re-Sn microparticles. The relief in treated patients, from the pain and inflammation, was observed clinically and by (99m)Tc-MDP perfusion scan.

Samarium-153 ethylenediamine tetramethylene phosphonate therapy for bone pain palliation in skeletal metastases.

BACKGROUND: Systemic therapy with radionuclides may be used for the treatment of patients with painful skeletal metastases owing to its efficacy, low cost and low toxicity. Imported radionuclides for pain palliation, like Strontium-89 are expensive; particularly for developing countries. In the Indian scenario, Samarium-153 (Sm-153) is produced in our own reactors and as a result, it is readily available and economical. AIM: We undertook this study to determine the efficacy and toxicity of single-dose Sm-153 ethylenediamine tetramethylene phosphonate as a palliative treatment for painful skeletal metastases. MATERIALS AND METHODS: Eightysix patients with painful skeletal metastases from various primaries, were treated with Sm-153 EDTMP at a dose of 37 MBq/kg. The effects were evaluated according to change in visual analogue pain score, analgesic consumption, Karnofsky performance score, mobility score and blood count tests, conducted regularly for 16 weeks. STATISTICS: Repeated measures analysis. RESULTS: The overall response rates were 73%, while complete response was seen in 12.4%. Reduction in analgesic consumption with improvement in Karnofsky performance score and mobility score, was seen in all responders. Response rates were 80.3 and 80.5% in breast and prostate cancer, respectively. One case, each of Wilms tumor, ovarian cancer, germ cell tumor testis, multiple myeloma, primitive neuroectodermal tumor and oesophageal cancer, did not respond to therapy. No serious side-effects were noted, except for fall in white blood cell, platelet and haemoglobin counts, which gradually returned to normal levels by six-eight weeks. CONCLUSION: Sm-153 EDTMP provided effective palliation in 73% patients with painful bone metastases: the major toxicity was temporary myelosuppression.

Technetium Tc-99m ethyl cysteinate dimer brain single-photon emission CT in mild traumatic brain injury: a prospective study.

PURPOSE: To explore the role of single-photon emission CT (SPECT) in initial diagnostic evaluation of patients with mild traumatic brain injury (MTBI) and to identify subgroups in which it may serve as a useful diagnostic tool. MATERIALS AND METHODS: Patients with MTBI seen during a 14-month period were prospectively included in this study. All patients had a CT of head within 12 hours of injury and SPECT by using technetium Tc99m ethyl cysteinate dimer (Tc99m-ECD) within 72 hours of injury. Both SPECT and CT findings were compared with clinical features such as posttraumatic amnesia (PTA), postconcussion syndrome (PCS), and loss of consciousness (LOC). RESULTS: Ninety-two patients with MTBI underwent SPECT in the study period. There were 28 children and 64 adults, with male-to-female ratio of 4.5 to 1. CT findings were abnormal in 31 (34%) and SPECT in 58 (63%). The most common abnormality was hypoperfusion in the frontal lobe(s) in adults and the temporal lobe in children. A significantly higher number of perfusion abnormalities were seen in patients with PTA (P = .03), LOC (P = .02), and PCS (P = .01) than in patients without these symptoms. Compared to CT, SPECT had a much higher sensitivity for detecting an organic basis in these subgroup, of patients (P < .05). CONCLUSION: Tc99m-ECD SPECT can be used as a complementary technique to CT in initial evaluation of patients with MTBI. It is particularly useful in patients having PCS, LOC, or PTA with normal CT scan.

188Rhenium(V)-dimercaptosuccinic acid loaded poly(lactic-co-glycolic)acid microspheres for targeted radiotherapy: production and effectivity.

Poly(lactic-co glycolic)acid (75:25) (PLGA) microspheres for the delivery of a radiation dose to tumors were synthesized after loading the 188Re(V) labeled DMSA. The 188ReO4- in place of 99mTcO4- was replaced to label DMSA, because of their structural and chemical similarities and to make the molecule site specific for radiotherapy. The radiolabeling efficiency of DMSA was more than 97% as confirmed by ITLC. A solvent evaporation technique was used to encapsulate DMSA in PLGA microspheres. Electron microscopy demonstrated the microspheres size ranged between 0.4-1.8 microm. As demonstrated by DSC, DMSA was encapsulated (20-30%) within the microspheres in solid solution, metastable molecular dispersion or crystallization forms. In vitro release studies confirmed the stability of DMSA.

Tc-99m tetrofosmin uptake in male breast cancer.

Breast carcinoma occurs rarely in men. Its imaging by mammography is difficult because male breast tissue is normally small in volume and adequate compression is not possible, which is a prerequisite for performing mammography. The authors describe a 65-year-old man with a right breast mass in whom the result of fine-needle aspiration cytology was inconclusive. A mammogram was also noncontributory because adequate compression was not possible as the mass was tender. Tc-99m tetrofosmin scintimammography showed intense focal uptake in the right breast. Excision biopsy confirmed the diagnosis of breast carcinoma.

Radionuclide studies in the evaluation of urinary tract infections.

OBJECTIVE: To estimate the prevalence of vesicoureteral reflux (VUR) and renal scarring in children presenting with culture proven urinary tract infections (UTI). DESIGN: Descriptive study. SETTING: Tertiary care hospital-based study. SUBJECTS: Thirty-two children with proven UTI were evaluated by means of an abdominal ultrasonogram (USG), Technetium-99m Dimercapto Succinic Acid (DMSA) scan and Direct Radionuclide Cystography (DRCG). A micturating cystourethrogram (MCU) was performed to rule out any structural abnormality and to grade VUR. RESULTS: A total of 64 renal units in 32 children were evaluated. DMSA scan showed scarring in 27 renal units (42.2%) in 16 patients. Bilateral renal scarring was more common in older (> 2 yr) children as compared to younger ones (89% Vs 43%; p < 0.05). USG detected abnormalities in 13 renal units (20.3%) in 7 cases. VUR was detected in 37.5% of children of all age group by DRCG. In contrast, MCU showed evidence of VUR in only 13/20 renal units with a sensitivity of 65% as compared to DRCG and did not pick up any additional VUR that could have been missed on the DRCG. Only 3/9 in < 2 yr, in contrast to 10/11 in > 2 yr were positive for VUR on MCU (p < 0.05). However, MCU detected evidence of cystitis in 3 children and a bladder diverticulum in one patient. CONCLUSION: Wherever available, DMSA scan should be considered as a part of the first line investigations in any patient presenting with UTI. DRCG can also be performed in the same sitting to screen for the presence of reflux particularly for girls.

Effect of synthetic progestins on the uptake of labelled testosterone and estradiol-17beta by the accessory genital organs of male rats.

PIP: The effect of pretreatment with norethindrone (NE) or 17-hydroxyprogesterone caproate (17-OHPC) on the uptake of tritiated testosterone and estradiol-17beta by the accessory sex organs of castrated and intact rats was investigated. A selective in vivo increase in the incorporation of tritiated testosterone and estradiol-17beta was observed at 48 hours after castration. The uptake of testosterone was greatest in the epididymis, while the maximum incorporation of estradiol-17beta was by the vas deferens. Pretreatment with NE or 17-OHPC decreased the incorporation of testosterone by all the accessory organs of castrated rats. NE decreased the incorporation of tritiated estradiol-17beta in the epididymis and seminal vesicles only, while 17-OHPC decreased the uptake in all accessory organs.^ieng