[Application of ICRP-103 in the calculation of effective dose associated to nuclear medicine tests]. / Aplicación de los factores de ponderación de la Comisión Internacional de Protección Radiológica 103 en el cálculo de la dosis efectiva asociada a las exploraciones de Medicina Nuclear.

OBJECTIVE: Re-evaluate the effective dose (E) of typical nuclear medicine procedures using the new ICRP-103 weighting factors and the latest dosimetry data and relate E with Background Equivalent Radiation Time (BERT). MATERIAL AND METHODS: Effective dose associated with radiopharmaceuticals and nuclear medicine procedures has been calculated for the following ages: adult, 15, 10, 5 and 1 year. Dosimetry data have been extracted from ICRP-106, ICRP-80, ICRP-53 and/or manufacturer's brochure. RESULTS: The relationship of the data of effective dose associated with radiopharmaceuticals and explorations is shown. The new tissue weighting factors result in a decreased value of the effective dose, except in cases that particularly affect the breast, in which it increases. The effective dose associated with nuclear medicine procedures is in the range 0.1-60 mSv. BERT ranges from a few days to 20 years. The effective dose associated to tests in children is generally higher than the effective dose for an adult. CONCLUSIONS: The results shown in this paper are an updated collection of effective dose values for commonly used radiopharmaceuticals in nuclear medicine. Expressing the effective dose equivalent time in units of natural radiation helps to explain issues associated with radiation exposure to patients and healthcare personnel.

[Somatostatin receptor scintigraphy in pediatric bronchial carcinoid tumor]. / Gammagrafía con análogos de la somatostatina en el diagnóstico y el seguimiento del carcinoide bronquial pediátrico.

INTRODUCTION: Carcinoid tumor is a rare neuroendocrine neoplasm with different locations, the most frequent ones during the pediatric age being the appendix and lung. Scintigraphy with (111)In-DTPA-d-Phe(1)-octreotide has led to an importance advance in the diagnosis of extension in carcinoid tumor patients. We present three pediatric patients with bronchial carcinoid studied with somatostatin analogue scintigraphy (SSRS). CLINICAL CASES: The first patient (9 years) was studied using the SSRS after surgery due to carcinoid tumor in the right lower lobe in which tumor remains was observed (this being clearer in the tomography study). The second patient (10 years) presented due to endobronchial tumor in the left lower lobe together with atelectasis of the LUL and emphysema of the LLL. Radiology imaging techniques suggested the differential diagnosis between the endobronchial carcinoid tumor or plasma cells or foreign body gramuloma. The SSRS showed an abnormal deposit of activity in the left hemithorax consisted with carcinoid tumor. No other areas suggesting metastasis were observed. After the surgery (endobronchial resection), new controls with SSRS showed absence of disease. The third patient (12 years) came after a lobectomy (RUL) due to bronchial carcinoid. The SSRS did not show any abnormal areas of activity. In the subsequent control (3 months), a deposit of activity was observed in the middle third of the right hemithorax, after which a lobectomy was performed (RLL and ML) that showed small remains of neuroendocrine carcinoid. Subsequent controls were negative. CONCLUSION: The SSRS has demonstrated great utility in the diagnosis, follow-up and staging of pediatric patients, carriers of neuroendocrine carcinoid tumors.

[Relative renal function based on DMSA uptake corrected for volume: normalized relative renal function]. / Función renal relativa basada en captación de ácido dimercaptosuccínico corregida por volumen: función renal relativa normalizada.

OBJECTIVE: Relative renal function (RRF) quantification based on dimercaptosuccinic acid (DMSA) uptake is an established method for determining differential renal function. An abnormal kidney size may lead to an alteration in its RRF value, although it has no dysfunction. Therefore, it is useful to correct RRF values taking into account relative renal volumes, thus obtaining the normalized relative renal function (NRRF). The feasibility of the method used for volume correction, differences with respect to usual quantification and different normality intervals were studied. MATERIAL AND METHODS: A total of 187 DMSA renal scintigraphies (130 children and 57 adults) were studied. RRF was quantified and volume corrected to obtain NRRF. Patients were classified as normal or pathological using various normality intervals for NRRF. A second classification was performed depending on how the diagnostic changed after volume correction. RESULTS: An increase of pathological diagnosis was observed after volume correction, mainly in children. Using an intermediate estimation for the normality interval, 53% of the initially pathological diagnosis for children may be caused simply by different renal volumes. CONCLUSIONS: NRRF provides complementary information to RRF and helps to distinguish between a smaller kidney and a really hypofunctioning one in cases with abnormal RRF.

[Evaluation of the usefulness of the antimyosin monoclonal antibody (AMA) uptake in the diagnosis of heart transplant (HT) rejection]. / Valoración de la utilidad del índice de captación de anticuerpos monoclonales antimiosina (AMA) en el diagnóstico de rechazo en el trasplante cardíaco (TC).

OBJECTIVE: To ascertain whether a given level of antimyosin monoclonal antibody (AMA) uptake in the endomyocardial biopsy (EMB) can identify patients with rejection. MATERIAL AND METHOD: 186 examinations were performed on 65 patients (8 women and 57 men) with orthotopic heat transplant (HT): Mean age 51 +/- 13 years. There were 3 examinations per patient (range 1-6). The studies were conducted 13 to 880 days after the HT. The C/p uptake indexes were obtained according to the Carrió y cols. method and the results were compared with the biopsy findings. Rejection was considered to be when the biopsy showed at least one site of necrosis. RESULTS: 1) We analyzed the C/P index in accordance with the post-HT interval and with the degree of rejection obtained by EMB. No group showed any significant differences between the patients with an without rejection (p > 0,05). 2) We applied a variable threshold based on post-HT interval, using an exponential curve defined on the basis of the interval of the values corresponding to patients without rejection and good progress compared with that of the rejection patients. This approach also did not contribute any improvement compared to the use of a fixed threshold due to the significant overlay of the values for patients with and without rejection. 3) Finally, we analyzed the individual evolution of the C/P indexes for each patient in terms of time. In patients whose clinical progress was good, the C/P indexes were observed to drop progressively over time. In those whose clinical progress was poor, abrupt increases in the index values were observed. CONCLUSION: We were unable to differentiate significantly between patients with and without rejection in EMB using fixed and variable thresholds of the C/P index. However, the different patterns of evolution for each patient provide information on the lack of complications and could be used as a follow-up technique.

[Effective doses associated to the usual multimodal examinations in nuclear medicine]. / Dosis efectivas asociadas a las exploraciones multimodales habituales en medicina nuclear.

OBJECTIVE: To know the effective doses (E) that can be given in the common multimodal procedures in nuclear medicine, Single Photon Emission Tomography and Positron Emission Tomography, combined with Computed Tomography, SPECT/CT and PET/CT. Effective dose will be expressed according to Background Equivalent Radiation Time (BERT) and the contribution of the CT scan to the total dose will also be studied. MATERIAL AND METHODS: The effective dose of each procedure has been calculated as the sum of the external radiation dose (CT part) and internal one (radiopharmaceutical administration). Data from each side were collected through extensive literature search. RESULTS: A range of minimum and maximum effective dose [E(min), E(max)] associated with each procedure is shown. These doses range from 0.5 to 49.1 mSv. BERT ranges from 2.6 months to 20.4 years. The CT contribution to the total effective dose varies from 2.1% to 93%, according to the image acquisition protocol and its purpose. Performing a diagnostic CT scan increases the dose up to a factor of 4.3 times compared to the dose used for CT acquisition for attenuation correction and anatomic localization. CONCLUSIONS: This article focus on the effective dose level that can be given in multimodal procedures, bearing in mind that the data are subject to constant changes and should be updated periodically. It is important to know the dosimetric impact when the CT scan is added. The application of optimized protocols according to the indication of the study reduces the patient's exposure without the loss of significant information.