Shaunak Navalkissoor

SPECT/CT in sentinel node imaging.

Sentinel node lymphoscintigraphy and biopsy has become standard practice for lymphatic staging in early-stage breast cancer and melanoma. More recently, sentinel node lymphoscintigraphy has also been used in head and neck squamous cell cancers and other solid tumours. Single photon emission computed tomography/computed tomography (SPECT/CT) is a new tool and this article reviews its potential application in sentinel node imaging. SPECT/CT provides complementary functional and anatomical information and has been shown to be superior to planar imaging in a number of indications. The advantages include more accurate anatomical localization, identification of false positives (due to contamination or spillover from the injection site), reduction in the number of false negatives (visualization of nodes not seen on planar imaging) and alteration of the surgical approach. We thus believe that sentinel lymph node SPECT/CT can provide valuable information before sentinel lymph node biopsy and advocate its use in a range of tumours such as truncal and head and neck melanomas.

The Impact of 68Ga-DOTATATE PET/CT Imaging on Management of Patients with Neuroendocrine Tumors: Experience from a National Referral Center in the United Kingdom

68Ga-DOTATATE PET/CT scanning is a widely accepted method for imaging of neuroendocrine tumors. This cross-sectional study was performed to review the first 8 y of patient data from a large 68Ga-DOTATATE PET/CT database in order to establish the impact of the modality on patient treatment and survival. Methods: Demographic data, clinical outcome, survival, and change in management after 68Ga-DOTATATE PET/CT were evaluated. Results: Between May 2005 and August 2013, 1,258 68Ga-DOTATATE PET/CT scans were obtained in 728 patients with confirmed or suspected neuroendocrine tumors. In most patients, the primary site was located in the midgut (26.4%). Analysis of NET grading in patients with known histopathologic data revealed that 35.7% had NET grade G1, 12.2% G2, and 8.7% G3. The most common indications for 68Ga-DOTATATE PET/CT were follow-up (24.4%) and initial tumor staging (23.4%). Of the 1,258 68Ga-DOTATATE PET/CT scans completed, 75.7% were positive and 24.3% negative; there were 14 false-positive and 29 false-negative scans. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 97%, 95.1%, 96.6%, 98.5%, and 90.4%, respectively. In 40.9% of patients, the treatment plan was changed after the scans, owing mainly to new, unexpected findings. Statistically significant differences in survival were shown between patients with G1, G2, and G3 grade tumors (P < 0.0001) and also between patients with bone metastasis versus patients with soft-tissue metastasis (P < 0.0001). Conclusion: 68Ga-DOTATATE PET/CT scanning is safe and influences management in a large proportion of patients. Prognosis was dependent on tumor grade, and the presence of bone metastasis was associated with worse overall survival.

Capecitabine and streptozocin ± cisplatin in advanced gastroenteropancreatic neuroendocrine tumours

BACKGROUND Cytotoxic chemotherapy is widely used for advanced, unresectable pancreatic and other gastrointestinal foregut neuroendocrine tumours (NETs) and the most commonly used regimen combines 5-fluorouracil with streptozocin. The NET01 trial was designed to investigate whether capecitabine combined with streptozocin was an acceptable regimen with or without adding cisplatin. METHODS Patients with advanced, unresectable NETs of pancreatic, gastrointestinal foregut or unknown primary site were randomised to receive three-weekly capecitabine (Cap) 625 mg/m(2) twice daily orally, streptozocin (Strep) 1.0 g/m(2) intravenously on day 1, with or without cisplatin (Cis) 70 mg/m(2) intravenously on day 1. The primary outcome measure was objective response. Secondary outcome measures included progression-free and overall survival, quality of life, toxicity and biochemical response. RESULTS 86 (44 CapStrep, 42 CapStrepCis) patients were randomised. Best objective response rate was 12% (95% confidence interval (CI)=2-22%) with CapStrep and 16% (95% CI=4-27.4%) with CapStrepCis. Disease-control rate was 80% with CapStrep and 74% with CapStrepCis. The estimated median progression-free and overall survival were 10.2 and 26.7 months for CapStrep and 9.7 and 27.5 months for CapStrepCis. 44% of CapStrep and 68% of CapStrepCis patients experienced grade ≥3 adverse events. INTERPRETATION The efficacies of the novel CapStrep±Cis regimens were very similar. CapStrep was better tolerated than CapStrepCis. The trial was registered as EudraCT: 2004-005202-71 and ISRCTN: 35124268.

Treatment of hepatocellular carcinoma (HCC) by intra-arterial infusion of radio-emitter compounds: Trans-arterial radio-embolisation of HCC

Traditional radiotherapy is only effective in treating hepatocellular cancer (HCC) in doses above 50 Gy, but this is above the recommended liver radiation exposure of about 35 Gy, which is an important limitation making this treatment unsuitable for routine clinical practice. Trans-arterial radio-embolisation (TARE), consists of delivery of compounds linked to radio-emitter particles which end up in hepatic end-arterioles or show affinity for the neoplasm itself, allowing localised delivery of doses beyond 120 Gy. These are well tolerated in patients treated with this type of internal radiation therapy. TARE for HCC is used for palliative treatment of advanced disease which cannot be treated in other ways, or for tumour down-staging before liver transplantation, or as adjuvant therapy for surgically resected HCC. Tumour response after TARE is between 25% and 60% if assessed by using RECIST criteria, and 80% by EASL criteria. In this review we outline the advantages and limitations of radio-emitter therapy including 131-I, 90-Y and 188-Re. We include several observational, and all comparative studies using these compounds. In particular we compare TARE to trans-arterial chemo-embolisation and other intra-arterial techniques.

The role of single-photon emission computed tomography/computed tomography in localizing parathyroid adenoma.

With hybrid imaging playing an increasingly important role in nuclear medicine, this article reviews the literature on single-photon emission computed tomography/computed tomography (SPECT/CT) in parathyroid scintigraphy. An understanding of parathyroid and neck anatomy is important for accurate reporting of these scans, as this can have an impact on the surgical approach used. The contribution of SPECT/CT over and above SPECT alone is greatest in terms of localization, particularly for ectopic tumours. There remains controversy on the role of SPECT/CT in eutopic tumours, especially when considering such factors as imaging time and the additional radiation dose.

Single photon emission computed tomography/computed tomography in the evaluation of neuroendocrine tumours: a review of the literature.

The scintigraphic investigation of neuroendocrine tumours such as carcinoids has depended on standard techniques such as 123I-metaiodobenzylguanidine and 111In-pentetreotide imaging. More recently, the use of PET techniques such as 68Ga-DOTATATE has been advocated. An alternative improved modality is high-quality single photon emission computed tomography/computed tomography (SPECT/CT), which has the advantages of better sensitivity and specificity and has shown improved localization in up to 60% of cases. These advantages are especially true for pancreatic and lymph node lesions. Overall, SPECT/CT can result in a change in clinical management in 25% of patients. Although it is possible to combine SPECT and CT performed at different time points, there is better anatomical localization and improved reporter confidence when SPECT and CT are performed simultaneously.

Single-photon emission computed tomography-computed tomography in imaging infection.

This review focuses on the current evidence available on the use of single-photon emission computed tomography–computed tomography (SPECT-CT) in infection imaging. The single-photon functional agents commonly used to image infection include In-111-labelled or Tc-99m-labelled leucocytes, Ga-67 citrate, Tc-99m-biphosphonates and radiolabelled antigranulocyte antibodies. Although many of these agents have been available for a long time, the development of hybrid SPECT-CT technology has led to a wider use of these agents. This review shows that the application of CT to single-photon imaging techniques for imaging infection can significantly improve the accuracy of the technique by increasing the specificity and better defining the location and extent of suspected disease. Hybrid fusion images also increase the confidence of the individual in reporting and seem to be applicable to a wide range of clinical situations. We believe that, overall, SPECT-CT, by providing a clearer assessment of whether infection is present and an accurate localization of the disease so that optimum treatment can be initiated, has a role in infection imaging .

Peptide Receptor Radionuclide Treatment and (131)I-MIBG in the management of patients with metastatic/progressive phaeochromocytomas and paragangliomas

Radionuclide therapy has been used to treat patients with progressive/metastatic paragangliomas (PGLs) and phaeochromocytomas (PCCs). The aim of the present study is to retrospectively compare the therapeutic outcomes of these modalities in patients with progressive/metastatic PCCs and PGLs.

Automated quantification with BRASS reduces equivocal reporting of DaTSCAN (123I-FP-CIT) SPECT studies.

BACKGROUND ¹²³I-FP-CIT (DaTSCAN) SPECT studies of the nigrostriatal pathway are a valuable tool in the diagnosis of movement disorders. However some scans are reported as equivocal with potential adverse consequences. We investigated whether the use of quantification of tracer uptake within the striatum can be used to reduce the number of equivocal reports. MATERIAL AND METHODS BRASS software (Hermes, Sweden) was used to quantify striatal tracer uptake in DaTSCAN studies of patients referred to our institution. Scans were quantified and numerical limits were determined to distinguish between normal and abnormal scans. Scans were then re-reported both with, and without, the use of quantification. Number of equivocal reports and accuracy of reporting between the two types of reporting were compared. RESULTS Scan reporting using quantification led to a significant reduction in the number of equivocal reports with no significant change in reporting accuracy. CONCLUSION Automated quantification of DaTSCAN studies with BRASS and the use of numerical limits can decrease the number of equivocal reports without affecting report accuracy.

Diffuse FDG renal uptake in lymphoma

In patients presenting with acute renal failure and known/suspected lymphoma, the diagnosis of diffuse renal involvement is important, as there is potential for rapid resolution with chemotherapy. Although FDG is excreted through the kidneys and focal renal disease may be difficult to identify, diffuse renal FDG is more easily recognized and is always abnormal. We report a patient presenting with acute renal failure and suspected lymphoma. F-18 FDG PET/CT study demonstrated diffuse increased FDG uptake in bilaterally enlarged kidneys. Following 1 cycle of chemotherapy, the renal function normalized. An interim F-18 FDG PET/CT demonstrated normal size and FDG uptake within both kidneys.