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Nuclear Medicine is a medical specialty that allows modern diagnostics and treatments using radiopharmaceuticals original radiotracers (drugs linked to a radioactive isotope). In Europe, radiopharmaceuticals are considered a special group of drugs and thus their preparation and use are regulated by a set of policies that have been adopted by individual member countries. The radiopharmaceuticals used in diagnostic examinations are administered in very small doses. So, in general, they have no pharmacological action, side effects or serious adverse reactions. The biggest problem associated with their use are the alterations in their biodistribution that may cause diagnostic errors. Nuclear Medicine is growing considerably influenced by the appearance and development of new radiopharmaceuticals in both the diagnostic and therapeutic fields and primarily to the impact of new multimodality imaging techniques (SPECT-CT, PET-CT, PET-MRI, etc.). It's mandatory to know the limitations of these techniques, distribution and eventual physiological alterations of radiopharmaceuticals, contraindications and adverse reactions of radiological contrasts, and the possible interference of both., (Copyright © 2013 SERAM. Published by Elsevier Espana. All rights reserved.)

Purpose: Stimulated thyroglobulin (Tg) and (131)I total-body scan (TBS) have been the mainstays of differentiated thyroid carcinoma (DTC), but now diagnostic TBS has been eliminated from some follow-up protocols. Nevertheless, Tg can be negative in the presence of thyroid tissue, and moderately elevated Tg poses management problems. The purpose of this study was to check how many patients have Tg negative but visible thyroid tissue and if diagnostic TBS could be clinically useful., Material and Methods: Retrospective review of 317 exams (stimulated Tg and TBS) of 128 patients with DTC. Patients with high-grade criteria and/or positive autoantibodies are excluded. Tg is considered positive if higher than the sensitivity level of the technique. TBS is positive if thyroid remnant, lymphatic node or metastases are detected. Results are classified in Tg and TBS concordant or discordant., Results: Discordant (131)I TBS and Tg were found in 74/317 studies (23.3%), 48 (65%) being TBS positive and Tg negative. None of 128 patients had a first post-surgery negative scan, but 13 (10%) were Tg negative, even two patients with lymph node uptake. One year after radioiodine treatment, 26 out of 115 patients (initially Tg and TBS concordant positive) showed Tg negative and TBS still positive due to cervical remnants (20 patients), lymph node uptake (one) and metastasis (five); 20 patients remained Tg and TBS positive, but 14 of them only showed thyroid remnants., Conclusions: We propose to perform periodic diagnostic TBS to improve Tg specificity, at least while neck thyroid activity is detected, even if Tg is negative.

Objective: The aim of this work is to determine the calibration factor for Sm-153 and evaluate the influence of the geometry in the activity measurements in order to administer accurately the activity to the patient., Methods: The calibration factor for Sm-153 was determinated using the Sm-153 sources commonly used in clinical practice and the calibrator response in a known calibration setting. The geometry correction factor for the vial and the plastic syringe was calculated using the real activity indicated by the manufacturer and the activity measured in the vial and in the plastic syringe., Results: The calibration factor obtained is 239 +/- 4 and the correction factor which takes in consideration the geometry is 0,87 +/- 0,07. The activity measured in the syringe is eighteen percent higher to activity measured in the vial., Conclusion: This method allows to measure accurately the activity of Sm-153 in vial and syringe applying this geometry correction factor to determine accurately the activity administered to the patient.

Objectives: To evaluate the applicability of sentinel node biopsy in NO carcinomas of the larynx., Materials and Methods: We carried out a prospective study in 19 patients with carcinoma of the larynx NO. We peritumorally infiltrate with 1 mCi 99mTc-labeled nanocolloidal albumin via rigid endoscopy in general anaesthesia. Sentinel node detection is performed with a gamma sonda during lymph node detection. The histological results of the sentinel node are compared with the excised neck dissection specimen., Results: Identification of sentinel node was successful in 17 patients (89.47%). In 11 patients the sentinel node was tumor negative reflecting the correct neck lymph node status (pNO). Three patients had metastases in the sentinel node. We observed three false- negative. The sensitivity of the technique was 50% (3/6) and the negative predictive value 78.6%., Conclusions: We think that more studies are needed to use the technique in the laryngeal cancer and that a correct selection of the patients is essential.

Objectives: This study shows the results obtained by the application of the sentinel node (SN) in oral and lip cancer and performs a lymphatic map of these tumours., Patients and Method: We prospectively studied 14 patients with lip and oral tumours, all of them N0. We injected colloidal particles of serum albumin labeled with Tc-99 peritumoraly and we located the SN intraoperatively. The SN was then sent for anatomopathological study., Results: Sentinel node was identified in all of the patients. In 11 of them the sentinel node was negative for metastases and correctly predicted the status of the neck. In 3 patients the sentinel node was the only node that contained metastases. There were no false negatives. The sensibility of the technique was 100%., Conclusions: The results showed that this technique is a feasible method for tumours in these locations and can avoid neck dissections in N0 patients.

This study aims to evaluate the contribution of the 99mTc-HMPAO labelled leukocyte in the prognostic assessment of patients with acute pancreatitis. We have compared the usual methods of prognostic evaluation (computed tomography CT and the Ranson clinical score scale) with the scintigraphic findings in 23 consecutive patients with a clinical diagnosis of mild or severe acute pancreatitis. All 6 patients with severe pancreatitis showed an uptake which was mostly mild. 9/17 patients with mild pancreatitis showed uptake, which also frequently had a low intensity. When the severity index of CT was compared with the leukocyte results, the only patient with a high severity index showed a grade 3 uptake. However, in over 50% of the patients with a low severity index, uptake, generally having a low intensity, was found. When the uptake degree was compared with the Ranson score level, we observed a predominance of mild uptake in both patients with mild and severe pancreatitis. Considering these results, we believe that the lack of uptake in the leukocyte study in a patient with acute pancreatitis can be interpreted as a good prognosis sign. The significance of the finding of uptake in the pancreatic area is uncertain and studies should be performed in larger sized samples.

There are several therapeutic alternatives in the local treatment of rheumatoid arthritis (RA): intraarticular corticosteroids, chemical synoviorthesis, surgical synovectomy and synoviorthesis with radioisotopes. We present the results of an observational study on radioisotopic synoviorthesis carried out in the Valencian health care area from January 1989 to May 1997 which included 108 synoviortheses performed in 51 patients. This study aimed to assess the efficacy and safety of radiosynoviorthesis in the treatment of RA which had not responded to conventional treatment. Good and moderate results were obtained in 76.2% of the cases, there being significant differences in the efficacy of synoviorthesis in patients with and without advanced radiographic alterations. There were few side effects (3.7%). We conclude that radiosynoviortesis is a useful and safe therapeutic tool in RA that does not respond to conventional treatment, that it is more effective in large joints with little cartilaginous deterioration and that its repeated use does not decrease the expected therapeutic effect.