Patients with end stage renal disease (ESRD) with or without dialysis are at a higher risk for coronary artery disease. Currently, screening for coronary artery disease (CAD) is not a standard practice in ESRD patients. Diagnosing and treating renal patients with cardiovascular disease is still a major clinical dilemma as there is no clear-cut algorithm. Various diagnostic modalities are available for screening and diagnosis of cardiovascular disease in renal patients. These investigations seem to have varied sensitivity and specificity due to many complex metabolic changes occurring constantly in patients with renal disease. The aim of this review is to investigate the role ofr outinelyused cardiacinvestigations inr elationto renalpatients andto seehow nuclearcar diologycan helpin early diagnosis of cardiovascular disease in this group of patients.

In patients with end stage renal disease on dialysis; cardiovascular disease is frequently under diagnosed because of the non-classical presentation of symptoms. The aim of the study was to (a) evaluate the importance and the diagnostic accuracy of ^99m Tc-Tetrofosmin myocardial perfusion scintigraphy (MPS) with pharmacological exercise (b) assess the progression of coronary heart disease in patients with renal failure using a semi-quantitative method. A retrospective review was performed in 141 patients (M=86, F=55) (Mean age 56 yrs) all whom underwent stress testing with adenosine using the standard dosage regimes and were imaged with a one-day stress/rest protocol using Tc-99m tetrofosmin. 36/141 patients had an additional second stress and rest ^99m Tc-myocardial perfusion scintigraphy with a mean interval of 15-months (range 12-30 months). The tomographic slices were reconstructed anduptake in the heart quantified and compared to a normal data set to remove reader bias. 95 out of 141 patients (67%) had abnormal scans, 69(73%) had reversible and 26(27%) irreversible defects. 27(28.4%) patients had perfusion abnormality involving a single territory, 35(36.8%) involving two territories, and 8(8.4%) three territories. In addition 25(26.3%) patients had diffuse or patchy perfusion abnormalities. In 36 patients who had 2 scans, there was evidence ofprogression of cardiac disease in 21/36 (58%) patients. Using objective measurement of myocardial perfusion, the vast majority of patients on dialysis have abnormal ^99m Tc-Tetrofosmin myocardial perfusion scintigraphy often in more than one territory. It would also appear that there is also progression of defects seen on myocardial perfusion scintigraphy over a short time period. Myocardial perfusion scintigraphies are therefore useful in the diagnosis and follow-up of patients with renal failure on dialysis.

Objective: Tc-99m MDP and Tc-99m HEDP are the conventional bone scintigraphy agents widely used for the last 30 years. Since then, a variety of new phosphonates including alendronate have replaced the older ones because of higher efficacy in bone disorders. In the present study we propose a method to radiolabel alendronate with Tc-99m and compare it with conventionally available agent (Tc-99m MDP) for bone imaging. Methods: Ready to use alendronate kits were produced using stannous chloride reduction method. The kit underwent in vitro and in vivo quality control tests in animals followed by human trial in more than 35 subjects. In many cases, both Tc-99m alendronate and Tc-99m MDP scans were done. Results: More than 98% radiolabeling was consistently achieved. Serum studies showed 47% protein binding and stability of the preparation up to 24 h. Animal biodistribution studies and blood clearance data supports similar bone uptake and faster blood clearance as compared to Tc-99m MDP. Bone scintigraphy with Tc-99m alendronate in humans suggests acceptable bone to soft tissue ratio at 90-120 min. Conclusions: The proposed method of radiocomplexation of alendronate is a viable option for preparing this radiopharmaceutical. Tc-99m alendronate gives acceptable images at 90-120 min post injection compared to 3-4 hrs with Tc-99m MDP. It has the potential to become an important bone-imaging agent because of easy availability, cost-effectiveness and the fact that MDP is now obsolete and may not be available easily as a drug.

Background: A retrospective study was performed to evaluate the utility of integrated PET/CT in localization of primary disease, detection of nodal/distant metastases, detection of residual/recurrent disease after therapy and its ability to predict long term outcome in patients with esophageal carcinoma. Methods: 70 paients (38 males, 32 females, age group 32 to 78 years) with Carcinoma of esophagus/Gastro-esophageal junction (41 with squamous cell carcinoma and 29 with adenocarcinoma) were included in the study. 23 cases (Category 1) underwent 18F-FDG PET/CT as a part of pre-surgical staging work up. All these cases also underwent a baseline diagnostic CT of the thorax and upper abdomen, with oral and intravenous (IV) contrast. 20 of these cases underwent surgery (esophagectomy with gastric pull up) based on the PET/CT staging. Diagnostic validation was by histopathologic examination of resected specimen in the operated cases. Data was compiled and the incremental value of PET/CT over CECT for the detection of primary tumor and lymph node metastasis was assessed. The remaining 47 cases, underwent PET/CT as part of post-therapy follow up for detection of residual or recurrent disease; 18 cases (Category 2) were post-surgery (+/− chemotherapy/radiation therapy) and 29 cases (Category 3) came following conservative management (Chemotherapy/Radiotherapy/Chemo-radiotherapy) only. Data was compiled and value of PET/CT in detection of residual/recurrent disease after therapy and its ability to predict long term patient outcome was studied. Results: In category 1, PET/CT and CT showed concordant abnormality (locally active disease/nodal disease) in 7 cases. In 08 cases PET/CT showed positive uptake in normal sized nodes. In 03 cases CECT showed enlarged nodes which were non-FDG avid on PET/CT. In 03 cases PET/CT showed distant metastases which were not detected by CT. In category 2 recurrence at anastomotic site was detected in 1 case, disease recurrence along with distant metastases was seen in 2 cases and only residual nodal disease without a local disease was seen in 3 cases by PET/CT. Twelve cases were reported as disease free of which 10 were alive at one year (83% one year survival rate), whereas both the patients detected to have local recurrence and metastasis died within a year (one year survival rate - nil). In category 3, eight cases showed no residual disease and 21 showed metabolically active disease. Of the 08 cases shown as disease free by PET/CT, 07 survived over the next one-year period (One year survival rate 87.5%) Conclusion: In PET/CT, PET and CT provide complementary information and help in accurate staging, early detection of recurrence and prognostication in cases of Carcinoma Esophagus.

Background: Carcinoma of unknown primary sites (CUP) is defined as the presence of histologically proven metastatic disease without evidence of a primary tumor. Purpose: The aim of this study was to prospectively assess the utility of integrated Positron Emission Tomography/Computed tomography (PET/CT) with ¹⁸ F-Fluro-deoxyglucose (FDG) in depicting the primary lesion in CUP as compared with PET & Contrast Enhanced Computed Tomography (CECT). Methods: 45 patients (34 males, age range 27-75 years and 11 females, age range 46-77 years) diagnosed with CUP were subjected to FDG PET/CT with the aim of locating the site of primary tumor. All patients underwent a conventional diagnostic work up that included CECT scan of the relevant parts of the body. The PET/CT images were evaluated separately as only PET images & fused PET/CT images. All potential sites of primary tumor detected by the CECT, PET & PET/CT imaging were subsequently sampled & verified by histopathologic examination as true positive or false positive. Data was compiled and the detection rate and positive predictive value for the detection of the primary tumors were calculated for CECT, PET & PET/CT. The incremental value of PET/CT over CECT and PET alone for the detection of primary tumor was assessed. Results: CECT detected a possible site of primary tumor in 10 out of 45 cases, of which 9 were true positive. PET/CT depicted the primary tumor in 16 of 45 patients. Of these 14 were true positive and two were false positive. PET alone detected a suspected primary tumor site in 22 of the 45 patients out of which 08 were false positive. In 31 patients (68.9%), the primary tumor site remained occult. PET/CT detected the primary in 55.6% more cases than CECT alone (14 vs 9). The detection rate for CECT, PET and PET/CT were 20%, 31.1% and 31.1% respectively. The positive predictive value of CT, PET & PET/CT were 90%, 63.6% & 87.5% respectively. Conclusion: Integrated PET/CT has higher detection rate for primary tumor in cases of CUP than CECT. Addition of CT information to PET images of PET/CT increases the diagnostic accuracy. Thus integrated PET/CT appears to be a better tool in detecting the site of primary in cases of CUP, than CECT or PET alone.

The purpose of the study was to assess the clinical impact of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) in the management of patients who were unsuitable candidates for transthoracic needle aspiration (TTNA) of solitary lung nodules. The PET study results of forty-six patients were retrospectively evaluated. The major indications for PET study were the inaccessibility of the lesion or the small size of the lung nodules for TTNA (n=16), a previous undiagnostic or a denied procedure (n=12), or massive chronic obstructive pulmonary disease (COPD) (n=13). A PET scan was also performed in 3 elderly patients and in 2 subjects treated with anticoagulant drugs. The patient's clinical history and the results of computed tomography (CT) were also evaluated to assess thepre-test likelihood of cancer (high, low or indeterminate probability) and their influence on the decision making process in comparison with PET results. No treatment was performed in 19/23 (83%) patients with negative PET studies and low or indeterminate pre-test likelihood for cancer, whereas a surgical assessment of lung nodules was obtained in the remaining 4 patients, all with high probability for tumour. All 19 patients with focal FDG lung nodule uptake had surgery or chemoradiotherapy irrespective of probability of cancer, whereas an antimicrobial therapy for infectious disease was performed in the 4 patients with equivocal PET studies and low or indeterminate likelihood. The results of FDG-PET study may influence the management of patients unsuitable for TTNA, whenever CT images do not strongly suggest cancer.

PET & PET/CT are increasingly being used for oncologic imaging. In lung cancers, FDG PET/CT is performed to stage the disease at initial presentation, assess response to conservative therapy and to detect recurrence following treatment. A 53 year old male, operated for resectable carcinoma lung, underwent a follow up PET/CT scan, six months after the surgery. PET/CT images were highly suggestive of a malignant lesion in the chest wall. Excision biopsy revealed a suture granuloma. The case highlights an uncommon but potential cause for false positive on FDG PET/CT, in cancer patients evaluated following a surgical intervention.

Conventionally ¹⁸ F-Fluorodeoxyglucose (FDG) Positron emission tomography (PET) has been considered to be of limited value for detection of bladder cancer because of interference by the FDG excreted in urine. An 83 year old male with urothelial carcinoma of the bladder underwent trans-urethral resection of bladder tumor (TURBT) and was post operatively advised FDG PET scan for assessing the residual locoregional disease and distant spread if any. We carried out a dual phase PET-CT scan with addition of intravenous frusemide and oral hydration. This modified scanning technique achieved adequate washout of urinary FDG and was successful in demonstrating the residual bladder tumor and its multi focal nature.