Clinical Significance of Pretreatment FDG PET/CT in MIBG-Avid Pediatric Neuroblastoma.

PURPOSE: 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging is well known to have clinical significance in the initial staging and response evaluation of the many kinds of neoplasms. However, its role in the pediatric neuroblastoma is not clearly defined. In the present study, the clinical significance of FDG-PET/computed tomography (CT) in 123I- or 131I-metaiodobenzylguanidine (MIBG)-avid pediatric neuroblastoma was investigated. METHODS: Twenty patients with neuroblastoma who undertook pretreatment FDG PET/CT at our institute between 2008 and 2015 and showed MIBG avidity were retrospectively enrolled in the present study. Clinical information-including histopathology, and serum markers-and several PET parameters-including SUVmax of the primary lesion (Psuv), target-to-background ratio (TBR), metabolic tumor volume (MTV), and coefficient of variation (CV)-were analyzed. The prognostic effect of PET parameters was evaluated in terms of progression-free survival (PFS). RESULTS: Total 20 patients (4.5 ± 3.5 years) were divided as two groups by disease progression. Six patients (30.0 %) experienced disease progression and one patient (5.0 %) died during follow-up period. There were not statistically significant in age, stage, MYCN status, primary tumor size, serum lactate dehydrogenase (LDH), neuron-specific enolase (NSE), and ferritin level between two groups with progression or no progression. However, Psuv (p = 0.017), TBR (p = 0.09), MTV (p = 0.02), and CV (p = 0.036) showed significant differences between two groups. In univariate analysis, PFS was significantly associated with Psuv (p = 0.021) and TBR (p = 0.023). CONCLUSIONS: FDG-PET parameters were significantly related with progression of neuroblastoma. FDG-PET/CT may have the potential as a valuable modality for evaluating prognosis in the patients with MIBG-avid pediatric neuroblastoma.

Radiation Dose-rate Reduction Pattern in Well-differentiated Thyroid Cancer Treated with I-131.

OBJECTIVE: To determine the patterns of dose rate reduction in single and multiple radioiodine (I-131) therapies in cases of well differentiated thyroid cancer patients. STUDY DESIGN: Analytical series. PLACE AND DURATION OF STUDY: Department of Nuclear Medicine and Radiation Physics, Multan Institute of Nuclear Medicine and Radiotherapy (MINAR), Multan, Pakistan, from December 2006 to December 2013. METHODOLOGY: Ninety three patients (167 therapies) with well differentiated thyroid cancer treated with different doses of I-131 as an in-patient were inducted. Fifty four patients were given only single I-131 therapy dose ranging from 70 mCi (2590 MBq) to 150 mCi (5550 MBq). Thirty nine patients were treated with multiple I-131 radioisotope therapy doses ranging from 80 mCi (2960 MBq) to 250 mCi (9250 MBq). T-test was applied on the sample data showed statistically significant difference between the two groups with p-value (p < 0.01) less than 0.05 taken as significant. RESULTS: There were 68 females and 25 males with an age range of 15 to 80 years. Mean age of the patients were 36 years. Among the 93 cases of first time Radio Active Iodine (RAI) therapy, 59 cases (63%) were discharged after 48 hours. Among 39 patients who received RAI therapy second time or more, most were discharged earlier after achieving acceptable discharge dose rate i.e 25 µSv/hour; 2 out of 39 (5%) were discharged after 48 hours. In 58% patients, given single I-131 therapy dose, majority of these were discharged after 48 hours without any major complications. CONCLUSION: For well differentiated thyroid cancer patients, rapid dose rate reduction is seen in patients receiving second or subsequent radioiodine (RAI) therapy, as compared to first time receiving RAI therapy.

Preparation and radiochemical control of 99mTc labeled blood pool agent for in vivo labelling of the red blood cells.

Our aim was to prepare cheap blood pool imaging kits by simplified method to overcome the burden on purchase department of MINAR, Nishtar Hospital, Multan, Pakistan. Secondarily, prompt supply of kits should save the time of patient during transportation. A total of 24 subjects selected for this study were equally divided into two groups. Mixture of stannous chloride and sodium pyrophosphate solution at pH 7 was injected to these subjects. Various concentrations (ranging from 200 to 800 microg) of stannous chloride dihydrate were injected to group one, followed by intravenous administration of technetium-99m (99mTc) pertechnetate at 30 min interval in 12 subjects. Labeling percentage of each sample was calculated afterwards followed by imaging under gamma camera. Each parameter was tested on three different patients and average of these three was calculated. In second set of experiments done on group two the same procedure was repeated in another 12 subjects, while keeping the concentration of Sn PYP constant at 400 microg. In this case, 99mTc was administered at different time intervals in different subjects ranging from 15 to 120 min (15, 30, 60 and 120 min) followed by calculation of labeling percentage and imaging under gamma camera. In group one, average percentage values of binding of red blood cells with 99mTc were 23.24, 84.88, 83.78 and 60.33% for concentrations of 200, 400, 600 and 800 microg, respectively. In group two, average percentage binging values of 22.26, 84.36. 55.54 and 28.67% were calculated at time intervals of 15, 30, 60 and 120 min, respectively. It is concluded from the results that the best blood pool imaging under gamma camera was observed for the concentration of 400 microg and the time interval of 30 min. The maximum percentage binding of red blood cells with 99mTc was calculated at concentration of 400 microg after 30 min interval that also correlated with imaging results.

Recent Trends in PET Image Interpretations Using Volumetric and Texture-based Quantification Methods in Nuclear Oncology.

Image quantification studies in positron emission tomography/computed tomography (PET/CT) are of immense importance in the diagnosis and follow-up of variety of cancers. In this review we have described the current image quantification methodologies employed in (18)F-fluorodeoxyglucose ((18)F-FDG) PET in major oncological conditions with particular emphasis on tumor heterogeneity studies. We have described various quantitative parameters being used in PET image analysis. The main contemporary methodology is to measure tumor metabolic activity; however, analysis of other image-related parameters is also increasing. Primarily, we have identified the existing role of tumor heterogeneity studies in major cancers using (18)F-FDG PET. We have also described some newer radiopharmaceuticals other than (18)F-FDG being studied/used in the management of these cancers. Tumor heterogeneity studies are being performed in almost all major oncological conditions using (18)F-FDG PET. The role of these studies is very promising in the management of these conditions.

ß-Thalassemia in Pakistan: a pilot program on prenatal diagnosis in Multan.

Prenatal diagnosis (PND) of ß-thalassemia has been underutilized in Pakistan because of a number of social and economic factors. National Institute for Biotechnology and Genetic Engineering Faisalabad in collaboration with Multan Institute of Nuclear Medicine and Radiotherapy Multan introduced free PND service for carrier couples of Multan district. Multan has a population of about 4 million. More than 170 couples registered for retrospective PND and in 2 years 105 PND were carried out through first trimester chorionic villus sampling. Almost 90% of these couples were unable to afford the cost of PND and would not have undergone the test as free service was not available. Monoplex and Multiplex Amplification Refractory Mutation System-polymerase chain reaction and genomic DNA sequencing were used for detection of IVS (intervening sequence)-I-5 (G-C), FSC (frameshift codon)-8/9 (+G), FSC-41/42 (-TTCT), IVS-I-1 (G-T), 619 bp deletion, and CD-15 (G-A) ß-globin mutations. Eighty-one percent (85/105) couples analyzed were in a consanguineous marriage. Twenty-three fetuses were found homozygous mutant and all couples opted for discontinuation of affected pregnancies. More families are registering for PND after establishment of this free and accessible PND service.

Klippel-Trenaunay syndrome.

Klippel-Trenaunay Syndrome (KTS) is a rare, congenital, vascular disorder affecting one or more limbs. Originally, it was defined as a triad including port wine stain, varicose veins and bony and soft tissue hypertrophy. We present a case of a 20-year-old female who walked with a limp. Because of swelling of right leg she was sent for Doppler study which picked up dilated arteries and increased blood flow velocity. The impression of KTS was further strengthened by unique nuclear medicine and radiological findings.

Studies of gastric emptying time in patients with non-ulcer dyspepsia.

PURPOSE: To assess the gastric emptying pattern of a standardized solid meal in patients with non-ulcer dyspepsia by using scintigraphic techniques. METHODS: Results for the half-emptying time for solids (T1/2) and percent clearance of solid meal at 60 min (C60) of patients (n=35) having non-ulcer dyspepsia according to Rome II criteria were compared with age- and sex-matched controls (n=28). Gastric emptying was studied by using egg omelette labelled with Tc tin colloid. Data acquisition was done using two protocols: dynamic acquisition was performed for the first 100 min and then static acquisition was carried out for up to 4 h. T1/2 and C60 were calculated from the computer-generated time-activity curve. RESULTS: The normal range of T1/2 was 29-88 min (mean+/-2 SD) among the control group. The mean T1/2 of the patient group was 160.1+/-96.1 min (P<0.01). Twelve of 22 male patients and 11 of 13 female patients had prolonged T1/2. The normal range of C60 was 92-28% (mean+/-2 SD) in the control group. The mean C60 of the patient group was 33.1+/-18.5% (P<0.01). Fifteen of 22 male patients and 11 of 13 female patients had shortened C60. CONCLUSION: Gastric emptying is significantly delayed in both men and women having non-ulcer dyspepsia as the T1/2 is prolonged and the C60 is shortened in a significant number of these patients. Radionuclide tests might offer an objective way of assessing this particular aspect of gastric physiology.