Br Mittal

Detailed evaluation of different 68Ge/68Ga generators: an attempt toward achieving efficient 68Ga radiopharmacy

The present study is aimed at carrying out a comparative performance evaluation of different types of (68)Ge/(68)Ga generators to identify the best choice for use in (68)Ga-radiopharmacy. Over the 1 year period of evaluation, the elution yields from the CeO2-based and SiO2-based (68)Ge/(68) Ga generators remained almost consistent, in contrast to the sharp decrease observed in the elution yields from TiO2 and SnO2-based generators. The level of (68)Ge impurity in (68)Ga eluates from the CeO2 and SiO2-based (68)Ge/(68)Ga generator was always <10(-3)%, while this level increased from 10(-3)% to 10(-1)% in case of TiO2 and SnO2-based generators. The level of chemical impurities in (68)Ga eluates from CeO2 and SiO2-based (68)Ge/(68)Ga generators was negligibly low (<0.1 ppm) in contrast to the significantly higher level (1-20 ppm) of such impurities in eluates from other two generators. As demonstrated by radiolabeling studies carried out using DOTA-coupled dimeric cyclic RGD peptide derivative (DOTA-RGD2), CeO2-PAN and SiO2-based generators are directly amenable for radiopharmaceutical preparation, whereas the other generators can be only used after post-elution purification of (68)Ga eluates. Clinically relevant dose of (68)Ga-DOTA-RGD2 was prepared in a hospital radiopharmacy for non-invasive visualization of tumors in breast cancer patients using positron emission tomography.

Development of a single vial kit formulation of [99mTc]‐labeled doxorubicin for tumor imaging and treatment response assessment‐preclinical evaluation and preliminary human results

The present study describes the successful radiolabeling of [99mTcO(-) 4 ] with doxorubicin, and the resultant product was formulated in to a ready-to-label lyophilized single vial kit preparation for convenient use in a routine clinical setting. The radiolabeled preparation of [99mTc]-doxorubicin exhibited a high radiolabeling efficiency of more than 95.0%, serum stability for up to 24 h, and shelf-life of lyophilized cold kits was more than 6 months. Animal imaging data in tumor-bearing mice demonstrated that [99mTc]-doxorubicin accumulated in the tumor site with high target (tumor) to non-target (contra-lateral thigh) ratio (3.2 ± 0.5). The ratio decreased to 1.2 ± 0.6 indicating a good response on follow up imaging performed after 2 weeks of doxorubicin treatment. [99mTc]-doxorubicin scintigraphic data in human volunteers supported the hepato-renal excretion of the radiotracer as reflected by the increased accumulation of the radiotracer as a function of time in intestine, kidneys, and urinary bladder. Further, imaging in patients (very limited number) indicated that the technique may be useful in the detection of active sarcoma and post treatment (surgery/chemotherapy) remission or absence of the disease. The technique, however, needs validation through further preclinical evaluation and imaging in a larger number of patients.

Tc99m MDP bone SPECT in a case of osteomyelitis of the skull.

A seven-year-old male child presented with swelling at the left temporal region. His skull X-ray was normal. A three-phase bone scan showed increased blood flow, soft tissue activity, and increased tracer concentration in the left temporal region. Single photon emission computed tomography (SPECT) imaging of the skull revealed full thickness involvement of the left temporal bone. Our case report shows that, in osteomyelitis of the skull, SPECT imaging provides significantly more information for identifying the extent and thickness of bone involvement.

Impact of Integrating Pet-Ct in Radiotherapy Planning of Non-small CellCarcinoma Lung: Dosimetric and Radiobiological Comparison

The integration of PET and CT scans allows the simultaneous use of biologic and anatomic imaging data for better delineating tumor and sparing normal critical structures. The aim of this study is to assess the impact on target volume delineation using CT vs. PETCT based plans, and to determine radiobiological effect on tumor and normal tissue by comparing Tumor control probability (TCP) & normal tissue complication probability (NTCP) of CT & PET-CT based plans. 15 patients of inoperable NSCLC planned for radical radiotherapy, underwent a planning CT scan of the thorax. Target volumes were contoured. Later PETCT images with the auto contoured MTV (Metabolic target volume) images, were fused with the planning CT images. Margins were similarly given to PETMTV for the generation of PET CTV and PET PTV. 3 Dimensional conformal radiotherapy (3DCRT) plans were made on the planning CT images and the planning PETCT images, and were compared dosimetrically and radio biologically. The study shows that the use of PETCT resulted in significant decrease in PETCT generated MTV versus GTV delineated on CT. Also, there was statistical significant decrease in the volume of the normal lung irradiated in terms of V40 and the MLD. TCP for PETCT based plans was significantly higher than that with CT based plans. Also, PETCT based planning resulted in a statistically significant decrease in the NTCP for lung and spinal cord. Therefore, the study concludes that incorporation of PETCT into radiotherapy planning of NSCLC is technically feasible and dosimetrically appealing strategy for patient treatment.

A systematic review of management of neuroendocrine tumors: An experience from a tertiary care centre from India

Neuroendocrine tumors (NETs) encompass a heterogeneous group of tumors demonstrating varied clinical behavior. The field has recently witnessed several important developments stemming from improvements in the histopathological classification schemes, advanced imaging techniques, and a deeper understanding of the molecular mechanisms underlying tumor progression. These tumors have indolent clinical courses, with long survival rates even for the patients with metastatic disease. The mainstay of treatment is surgery. Somatostatin analogs play a key role in controlling the symptoms; however, they are seldom associated with tumor regression. Traditional cytotoxic chemotherapies have a very limited role in well differentiated NETs, but platinum based chemotherapy is highly effective in neuroendocrine carcinomas. Recently, the biological targeted agents have shown promise in patients with metastatic disease. Evolving modalities like peptide receptor targeted therapies and radioembolization have opened up new avenues in refractory and advanced disease.

Radiation surveillance in and around cyclotron facility

The cyclotron is the most widely used particle accelerator for producing medically important radio nuclides. Many medical centers in India have installed compact medical cyclotrons for on-site production of short-lived positron-emitting radio nuclides such as 18F, 13N, and 11C. A mandatory requirement for cyclotron installation is radiation control permit from Atomic Energy Regulatory Board. Cyclotron radiation survey is an integral part of the overall radiation safety in the cyclotron facility. Radiation surveillance in and around a newly installed cyclotron was performed using ionization chamber counter and Geiger Muller counter before, during and after operating the cyclotron. The readings were recorded at various locations where a high radiation field was expected. The results were recorded, tabulated and analyzed. The highest exposure level (0.93 μSv) was found at the back wall of the radiochemistry lab facing the cyclotron vault. Reason for the high exposure of 0.93 μSv/h: Synthesis of 18F-Fluoro-Deoxy-Glucose (18F-FDG) was going in the synthesis module and activity (18F) was present in the synthesis module when reading was taken. All other values were found to be below the recommended levels of exposure.

Noninvasive treatment of keloid using customized Re‐188 skin patch

Keloids are developed as fibrotic scar at the site of surgery or trauma and often enlarge beyond the original scar margins. Re‐188 colloid coated customized patch was superficially fixed onto the lesion for 3 hrs. The same patch was reapplied on the lesion on third day for 3 hrs. The patients were followed up at 1, 3,6 and 12 months post treatment. The size and elevation of the keloid lesion was reduced after treatment. The total radiation dose from the patch (day‐1 and day‐3) was 100 Gy/mCi of Re‐188. The radioactive patch treatment of keloids is noninvasive, painless and safe with prolonged outcome.

FLT PET/CT Is Better Than FDG PET/CT in Differentiating Benign From Malignant Pancreatobiliary Lesions.

Purpose 18F-fluorothymidine (FLT), unlike FDG, is incorporated exclusively into DNA and is considered a specific marker of cell proliferation. The role of FLT PET/CT scan in differentiating benign from malignant pancreatobiliary tumors is unknown. Patients and Methods Twenty-five suspected pancreatobiliary tumors on contrast-enhanced CT (CECT) scan in 23 patients were evaluated by FDG PET/CT and FLT PET/CT scans. The histopathology or fine-needle aspiration cytology was considered as criterion standard for the diagnosis. Surgeons were blinded to FLT PET/CT results. Management decision was guided by clinical and CECT scan and FDG PET/CT. Results Five of 23 patients had metastatic disease on CECT imaging. The remaining 18 underwent exploratory laparotomy. Two of them had synchronous lesions. Histopathology/fine-needle aspiration cytology confirmed malignancy in 17 lesions and benign disease in the remaining 8 lesions. All 8 benign lesions were negative on FLT PET/CT. Seven of the 8 benign lesions were clinically diagnosed as malignancy on CECT and FDG PET/CT. The specificity, positive predictive value, and accuracy were higher for FLT PET/CT (100%, 100%, and 92%) compared with CECT (12.5%, 70.83%, and 72%) and FDG PET/CT (12.50%, 69.57%, and 68%). However, the sensitivity of FLT PET/CT (88.24%) was similar to CECT (100%) and FDG PET/CT (94.12%). Conclusions Molecular-based FLT PET/CT is a better imaging than FDG PET/CT in differentiating benign from malignant lesions in the pancreatobiliary region. It has a potential to bring down the incidence of preventable radical resection in suspected pancreatobiliary tumors.

(18)F-FDG Positron Emission Tomography in Multifocal Pyomyositis.

18F-Fluoro-deoxyglucose–positron emission tomography/computed tomography findings in a case presenting with pyomyositis are presented in this report.

Role of Nuclear Medicine in Infection Imaging

A variety of conventional imaging modalities such as radiography, computed tomography and magnetic resonance imaging are available for evaluation of osteomyelitis. The diagnosis of acute osteomyelitis is relatively straight forward. Conventional imaging modalities perform poorly when there is a previous insult (fracture, trauma and infection) to the bone. The limitations of the conventional imaging modalities necessitate utilization of functional modalities. Nuclear medicine techniques are ideally suited for these patients.