Radiation dose produced by patients during radiopharmaceutical incorporation in nuclear medicine diagnostic procedures.

OBJECTIVES: The aim of this study was to assess the dose received by members of the public due to close contact with patients undergoing nuclear medicine procedures during radiopharmaceutical incorporation, and comparing it with the emitted radiation dose when the test was complete, in order to establish recommendations. MATERIAL AND METHODS: A prospective study was conducted on 194 patients. H*(10) dose rates were measured at 0.1, 0.5, and 1.0m after the radiopharmaceutical administration, before the image acquisition, and at the end of the nuclear medicine procedure. Effective dose for different close contact scenarios were calculated, according to 95th percentile value (bone scans) and the maximum value (remaining tests). RESULTS: During the radiopharmaceutical incorporation, a person who stays with another injected patient in the same waiting room may receive up to 0.59 mSv. If the patient had a medical appointment, or went to a restaurant or a coffee shop, members of the public could receive 23, 43, and 22 µSv, respectively. After finishing the procedure, these doses are reduced by a factor 3. In most of the studies, the use of private instead of public transport may reduce the dose by more than a factor 6. CONCLUSION: It is recommended to increase the distance between the patients during the radiopharmaceutical incorporation and to distribute them according to the diagnostic procedure. Patients should be encouraged to use private instead of public transport. Depending on the number of nuclear medicine outpatients per year attended by a physician, it could be necessary to apply restrictions.

Radiation dosimetry and biodistribution in non-human primates of the sodium/iodide PET ligand [(18)F]-tetrafluoroborate.

BACKGROUND: [(18)F]-tetrafluoroborate is a PET radiotracer taken up by the sodium/iodide symporter (NIS). Albeit the in vivo behavior in rodents is similar to the (99m)Tc-pertechnetate, no studies exist in primates or in humans. The aims of this study were to evaluate the biodistribution of [(18)F]-tetrafluoroborate in non-human primates with PET and to estimate the absorbed dose in organs. METHODS: Whole-body PET imaging was done in a Siemens ECAT HR+ scanner in two male Macaca fascicularis monkeys. After an i.v. injection of 24.93 ± 0.05 MBq/kg of [(18)F]-tetrafluoroborate, prepared by isotopic exchange of sodium tetrafluoroborate with [(18)F]-fluoride under acidic conditions, eight sequential images from the head to the thigh (five beds) were collected for a total duration of 132 min. The whole-body emission scan was reconstructed applying attenuation and scatter corrections. After image reconstruction, three-dimensional volumes of interest (VOIs) were hand-drawn on the PET transaxial or coronal slices of the frame where the organ was most conspicuous. Time-activity curves for each VOI were obtained, and the organ residence times were calculated by integration of the time-activity curves. Human absorbed doses were estimated using the OLINDA/EXM software and the standard human model. RESULTS: [(18)F]-tetrafluoroborate was able to discriminate clearly the thyroid gland with an excellent signal-to-noise ratio. Most of the radiotracers (residence time) are localised in the organs that express NIS (stomach wall, salivary glands, thyroid, olfactory mucosa), are involved in excretion (kidneys and bladder), or reflect the vascular phase (heart and lungs). Considering the OLINDA source organs, the critical organs were the stomach wall, thyroid and bladder wall, with absorbed doses lower than 0.078 mGy/MBq. The effective dose was 0.025 mSv/MBq. CONCLUSIONS: [(18)F]-tetrafluoroborate is a very useful radiotracer for PET thyroid imaging in primates, with a characteristic biodistribution in organs expressing NIS. It delivers an effective dose slightly higher than the dose produced by (99m)Tc-pertechnetate but much lower than that produced by radioiodine in the form of (131)INa, (123)INa, or (124)INa.

[¹8F]fluorothymidine-positron emission tomography in patients with locally advanced breast cancer under bevacizumab treatment: usefulness of different quantitative methods of tumor proliferation.

OBJECTIVES: To investigate quantitative methods of tumor proliferation using 3'-[(18)F]fluoro-3'-deoxythymidine ([(18)F]FLT) PET in patients with breast cancer (BC), studied before and after one bevacizumab administration, and to correlate the [(18)F]FLT-PET uptake with the Ki67 index. MATERIAL AND METHODS: Thirty patients with newly diagnosed, untreated BC underwent a [(18)F]FLT-PET before and 14 days after bevacizumab treatment. A dynamic scan centered over the tumor began simultaneously with the injection of [(18)F]FLT (385 ± 56 MBq). Image derived input functions were obtained using regions of interest drawn on the left ventricle (LV) and descending aorta (DA). Metabolite corrected blood curves were used as input functions to obtain the kinetic Ki constant using the Patlak graphical analysis (time interval 10-60 min after injection). Maximum SUV values were derived for the intervals 40-60 min (SUV40) and 50-60 min (SUV50). PET parameters were correlated with the Ki67 index obtained staining tumor biopsies. RESULTS: [(18)F]FLT uptake parameters decreased significantly (p<0.001) after treatment: SUV50=3.09 ± 1.21 vs 2.22 ± 0.96; SUV40=3.00 ± 1.18 vs 2.14 ± 0.95, Ki_LV(10-3)=52[22-116] vs 38[13-80] and Ki_DA(10-3)=49[15-129] vs 33[11-98]. Consistency interclass correlation coefficients within SUV and within Ki were high. Changes of SUV50 and Ki_DA between baseline PET and after one bevacizumab dose PET correlated with changes in Ki67 index (r-Pearson=0.35 and 0.26, p=0.06 and 0.16, respectively). CONCLUSIONS: [(18)F]FLT-PET is useful to demonstrate proliferative changes after a dose of bevacizumab in patients with BC. Quantification of tumor proliferation by means of SUV and Ki has shown similar results, but SUV50 obtained better results. A correlation between [(18)F]FLT changes and Ki67 index was observed.

[Validation of segmentation techniques for positron emission tomography using ex-vivo images of oncological surgical specimens]. / Validación de técnicas de segmentación para la tomografía por emisión de positrones mediante imágenes ex-vivo de piezas quirúrgicas oncológicas.

OBJECTIVE: To design a novel ex-vivo acquisition technique to establish a common framework to validate different segmentation techniques for oncological PET images. To evaluate several automatic segmentation algorithms on this set of images. MATERIAL AND METHODS: In 15 patients with cancer, ex-vivo PET studies of surgical specimens removed during surgery were performed after injection of (18)F-FDG. Images were acquired in two scanners: a clinical PET/CT and a high-resolution PET scanner. Real tumor volume was determined in each patient, and a reference image was generated for segmentation of each tumor. Images were segmented with 12 automatic algorithms and with a standard method for PET (relative threshold at 42%) and results were evaluated by quantitative parameters. RESULTS: It has been possible to demonstrate by segmentation of PET images of surgical specimens that on high resolution PET images, 8 out of 12 evaluated segmentation techniques outperformed the standard method, whose value is 42%. However, none of the algorithms outperformed the standard method when applied on images from the clinical PET/CT. Due to the great interest of this set of PET images, all studies have been published on the Internet in order to provide a common framework for validation and comparison of different segmentation techniques. CONCLUSIONS: We have proposed a novel technique to validate segmentation techniques for oncological PET images, acquiring ex-vivo PET studies of surgical specimens. We have demonstrated the usefulness of this set of PET images by evaluating several automatic segmentation algorithms.

Quantitative volumetric analysis of gliomas with sequential MRI and ¹¹C-methionine PET assessment: patterns of integration in therapy planning.

PURPOSE: The aim of the study was to evaluate the volumetric integration patterns of standard MRI and (11)C-methionine positron emission tomography (PET) images in the surgery planning of gliomas and their relationship to the histological grade. METHODS: We studied 23 patients with suspected or previously treated glioma who underwent preoperative (11)C-methionine PET because MRI was imprecise in defining the surgical target contour. Images were transferred to the treatment planning system, coregistered and fused (BrainLAB). Tumour delineation was performed by (11)C-methionine PET thresholding (vPET) and manual segmentation over MRI (vMRI). A 3-D volumetric study was conducted to evaluate the contribution of each modality to tumour target volume. All cases were surgically treated and histological classification was performed according to WHO grades. Additionally, several biopsy samples were taken according to the results derived either from PET or from MRI and analysed separately. RESULTS: Fifteen patients had high-grade tumours [ten glioblastoma multiforme (GBM) and five anaplastic), whereas eight patients had low-grade tumours. Biopsies from areas with high (11)C-methionine uptake without correspondence in MRI showed tumour proliferation, including infiltrative zones, distinguishing them from dysplasia and radionecrosis. Two main PET/MRI integration patterns emerged after analysis of volumetric data: pattern vMRI-in-vPET (11/23) and pattern vPET-in-vMRI (9/23). Besides, a possible third pattern with differences in both directions (vMRI-diff-vPET) could also be observed (3/23). There was a statistically significant association between the tumour classification and integration patterns described above (p < 0.001, κ = 0.72). GBM was associated with pattern vMRI-in-vPET (9/10), low-grade with pattern vPET-in-vMRI (7/8) and anaplastic with pattern vMRI-diff-vPET (3/5). CONCLUSION: The metabolically active tumour volume observed in (11)C-methionine PET differs from the volume of MRI by showing areas of infiltrative tumour and distinguishing from non-tumour lesions. Differences in (11)C-methionine PET/MRI integration patterns can be assigned to tumour grades according to the WHO classification. This finding may improve tumour delineation and therapy planning for gliomas.

[Neuroimaging in brain tumors]. / Neuroimagen de los tumores cerebrales.

Advances in neuroimaging have modified diagnosis, treatment and clinical management of brain tumors. However, neuropathological study remains necessary in order to get the best clinical management. Surgery and radiotherapy planning are imaging-dependent procedures, and MRI is the standard imaging modality for determining precisely tumor location and its anatomical relationship with surrounding brain structures. In high-grade tumors it has been accepted that tumoral areas with contrast uptake in CT, or T1-weighted MRI contrast enhancement corresponds to solid tumor. However, relationship between MRI and invasive tumor areas remains less defined. Therefore, it is generally accepted that conventional MRI is not sufficient to delineate the real extension of brain tumors. In recent years, PET using 18FDG and amino acid radiotracers ((11)C-Methionine, (18)FDOPA, (18)FET) and SPECT with (201-)Thallium, as well as advanced MRI sequences (Perfusion, Diffusion-weighted, Diffusion tensor imaging and tractography), and functional MRI, have added important complementary information in the characterization, therapy planning and recurrence differential diagnosis of brain tumors. In this continuing education review of neuroimaging in brain tumors, technical aspects and clinical applications of different imaging modalities are approached in a multidisciplinary way.

[Positron emission tomography in breast cancer]. / Tomografía por emisión de positrones en el cáncer de mama.

PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appear at a very early phases in the tumoral process. The main limitation of PET in breast cancer is the detection of small tumor lesions and axillary micrometastases. However it offers important information in the staging of high risk patients, in clinical relapse or in therapeutic evaluation. The new PET-CT devices offer advantages over conventional techniques. It provides a greater precision in the localization of tumoral foci. In spite of current difficulties for clinical applications, fluoro-estradiol (18F-ES) offers the possibilty of studying the presence of estrogenic receptors both in the primary and in the metastases. It may prove to be a useful tool to obtain information about therapeutic management and prognosis of breast cancer.

[New horizons in breast surgery. Radioguided surgery and selective sentinel node biopsy]. / Nuevos horizontes en cirugía mamaria. Cirugía radioguiada y biopsia selectiva de ganglio centinela.

Although needle-wire localization is the most commonly used localization technique for nonpalpable breast lesion biopsy, the technique of radioguided occult lesion localization (ROLL), is becoming increasingly used for open-surgery diagnosis in such cases. Sentinel lymph node biopsy(SLNB) is based on the hypothesis that lymphatic drainage from a tumor reaches the sentinel node(SLN) first and that it can be identified accurately and removed. If SLN exactly reflects the lymph-node status, a negative SLN for metastasis might allow complete axillary lymph node dissection (ALDN) to be avoided.

PET and prostate cancer.

The diagnosis of prostate cancer leaves some questions without answers. The different diagnostic techniques are limited in three situations: (1) staging of the tumour: identification of node involvement, (2) quantification of the tumour volume and its location inside the gland, (3) premature identification of relapse after radical treatment. These are the three problems that we need to consider in the diagnosis of prostate carcinoma. Imaging techniques can tell us the morphological alterations in the structures and organs. Positron emission tomography (PET) introduces a new way of identifying damage by counting metabolic activity. The tracers are substances that are marked with a radioactive molecule that is picked up more readily by the tumours. The presence of these substances in a set anatomic zone means higher consumption and therefore more metabolic activity. The radiotracer most frequently used in PET is glucose marked with fluoride 18. The first studies with marked glucose and prostate tumours started at the end of the 1990s. There are many contradictions in the results of these studies due to renal elimination, which produces an accumulation in the urinary tract and does not correctly show the prostate zone and iliobturator nodes area, and its capitation by zones with inflammatory process or prostatic hyperplasia. Choline is a substance that is present in cellular membranes. When it is marked with carbon 11, it changes to a new tracer. This radiotracer has affinity with prostate damage and allows the better differentiation of malignant from benign processes. It also has the advantage of the absence of renal elimination. Trials that used choline marked with carbon 11 (11C choline) are beginning to obtain very promising results. This union of a method that identifies metabolic activity with an imaging technique increases the sensitivity in the diagnostic test and can help find the exact location of the 11C choline deposits. The PET-CT combines the PET with computerised tomography. The 11C choline PET-CT is presented as a promising technique for answering the three problems mentioned above.

Cardiac surgery with deep hypothermic circulatory arrest produces less systemic inflammatory response than low-flow cardiopulmonary bypass in newborns.

OBJECTIVE: We sought to compare low-flow cardiopulmonary bypass with deep hypothermic circulatory arrest in respect to the influence on the systemic inflammatory response. METHODS: Twenty-three infants weighing less than 10 kg and scheduled for repair of congenital malformations were enrolled in a randomized, controlled study. Eleven patients underwent cardiac surgery with deep hypothermic circulatory arrest (the DHCA group). Low-flow cardiopulmonary bypass was used in another 12 patients (the LF group). Interleukin 6 and 8 and anaphylatoxin C3a levels were measured 6 times perioperatively. Also, perioperative weight gain and a radiologic soft-tissue index were compared. RESULTS: All patients had an uneventful clinical course. Duration of deep hypothermic circulatory arrest was 40 +/- 4 minutes; the bypass time was significantly shorter in the DHCA group (85 +/- 8 vs 130 +/- 19 minutes). However, the duration of the operation was similar in both groups (245 +/- 30 vs 246 +/- 30 minutes). During cardiopulmonary bypass (rewarming), the concentration of C3a (3751 +/- 388 vs 5761 +/- 1688 ng/mL, mean +/- SEM) was significantly lower in the DHCA group than in the LF group. The interleukin 8 level was significantly lower, and the interleukin 6 level had a tendency to be lower in the DHCA group compared with levels in the LF group. There was less weight gain on the first postoperative day in the DHCA group (65 +/- 61 vs 408 +/- 118 g). The soft-tissue index suggested reduced edema formation in the DHCA group. CONCLUSION: Deep hypothermic circulatory arrest produces less systemic inflammatory response than low-flow cardiopulmonary bypass. In addition, there is an indication of less fluid accumulation postoperatively.

Capillary leak syndrome after cardiopulmonary bypass in elective, uncomplicated coronary artery bypass grafting operations: does it exist?

OBJECTIVE: Operations coupled with cardiopulmonary bypass may provoke a systemic inflammatory response, and it has been suggested that this responses causes capillary leakage of proteins, edema formation, and even organ failure. However, capillary leak syndrome is mainly a clinical diagnosis and has not been verified as yet by actual demonstration of protein leakage from the circulation. We have therefore measured the disappearance of labeled plasma protein before and after cardiopulmonary bypass. METHODS: Sixteen patients scheduled for elective coronary artery bypass grafting were enrolled in a prospective controlled study. The cardiopulmonary bypass circuit was primed with crystalloids only. Tumor necrosis factor alpha, interleukin 6, interleukin 8, anaphylatoxin C3a, and terminal complement complex C5b9 levels were determined before, during, and 3 hours after cardiopulmonary bypass. The transvascular escape rate of plasma protein from the intravascular compartment was assessed by measuring the disappearance of intravenously injected Evans blue dye before and during the third hour after cardiopulmonary bypass. RESULTS: A significant inflammatory response could be demonstrated by means of the 5 measured mediators after bypass. The maximal increase, as compared with the baseline value, was found for interleukin 6 (36-fold). The transvascular escape rate of Evans blue dye was similar before and after bypass (7.6 +/- 0.6%/h vs 7.3 +/- 0.6%/h). CONCLUSIONS: The above data confirm the systemic inflammatory response induced by cardiopulmonary bypass. Contrary to expectations, the transvascular escape rate of Evans blue dye did not change when comparing values before and after bypass. The data do not support the concept of increased protein leakage in the exchange vessels after bypass. We were unable to demonstrate a capillary leak syndrome.

[Clinical value of positron emission tomography with F-18-FDG in the follow up of patients with cancer of the ovary]. / Valor clínico de la tomografía de emisión de positrones con F-18-FDG en el seguimiento de pacientes con cáncer de ovario.

BACKGROUND: Positron emission tomography with fluor-18-deoxyglucose (PET-FDG) is an efficient technique for the detection of tumoural tissue. The aim of the paper is to evaluate the PET-FDG in the diagnosis of residual disease or relapse in patients with cancer of the ovary. METHODS: A total of 24 patients, diagnosed and treated for cancer of the ovary with surgery and subsequent chemotherapy, were included. With 12 patients the study was carried out prior to second-look surgery, and with the other 12 after objectivising an increase of the tumoural marker in the follow up. Abdominal-pelvic CAT, determination of the seric levels of CA-125 and PET-FDG of thorax, abdomen and pelvis were carried out on all patients. The PET-FDG was evaluated in a qualitative way through the visual study of the images, and quantitatively through the SUV or standard uptake value. The definitive diagnosis was confirmed through an anatomopathological study in 13 cases and through clinical follow up in the rest with an average of 11.2+/-5.4 months (range 6-24). RESULTS: A CA-125 value higher than 35 UI/ml was considered positive, obtaining a sensitivity of 77% and a specificity of 100%. The sensitivity of the CAT was 23% and the specificity 91%. With the FDG-PET sensitivity was 92% and the specificity 90%. A SUV value >or= 3 was considered pathological, obtaining the same results as with the visual evaluation. The FDG-PET was positive in 5 patients with non-conclusive CAT, 4 with negative CAT and 2 with negative CA-125. CONCLUSION: These preliminary results suggest that the FDG-PET could be useful in the detection of disease in the follow up of patients treated for cancer of the ovary. The FDG-PET could be efficient in the differentiation between residual disease or recurrence, as opposed to sequels to the treatment, when the CAT is not conclusive due to anatomical distortion, since it permits the detection of tumoural lesions undetected by the radiological image techniques but metabolically active. The FDG-PET could be more sensitive than an increased marker value, and facing an increase of the latter it permits a non-invasive localisation of the disease.

Effect of C1-esterase-inhibitor on capillary leak and inflammatory response syndrome during arterial switch operations in neonates.

OBJECTIVE: To determine if prophylactic administration of C1-esterase-inhibitor would have a beneficial effect on postoperative weight gain and the inflammatory response in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB). DESIGN: Randomized, double-blinded study. SETTING: University-affiliated heart center. PARTICIPANTS: Twenty-four neonates with transposition of the great arteries. INTERVENTIONS: In group inhibitor (INH) patients (n = 12), 100 IU/kg of C1-esterase-inhibitor (Berinert) was given 30 minutes before CPB. In group placebo (P) patients (n = 12), placebo was administered instead. Interleukin (IL)-6, C3a anaphylatoxin, C1 activity, prekallikrein, Hageman factor, D-dimers, and clinical parameters were measured 6 times perioperatively. MEASUREMENTS AND MAIN RESULTS: All 24 patients had an uneventful clinical course. Mean arterial pressure and pulmonary oxygenation after CPB were superior in group INH patients. The weight gain on postoperative days 1 to 4 was significantly less in group INH patients compared with group P (55 +/- 59 g vs. 340 +/- 121 g, day 1). The concentration of IL-6 (76 +/- 17 pg/mL vs. 262 +/- 95 pg/mL during CPB) was significantly lower in group INH patients compared with group P patients. In contrast, no influence on C3a anaphylatoxin and coagulation factors was found. CONCLUSION: Prophylactic application of C1-esterase-inhibitor in neonates undergoing arterial switch operations produces less inflammatory response compared with placebo. This difference may have contributed to improved clinical parameters, including less weight gain postoperatively.

Low preoperative antithrombin activity causes reduced response to heparin in adult but not in infant cardiac-surgical patients.

UNLABELLED: We evaluated the interaction of preoperative antithrombin (AT) activity and intraoperative response to heparin in cardiac surgery. Heparin anticoagulation is essential during cardiopulmonary bypass (CPB). Heparin itself has no anticoagulant properties, however it causes a conformational change of the physiologic plasma inhibitor AT that converts this slow-acting serine protease inhibitor into a fast acting one. Thus, adequate AT activity is a prerequisite for sufficient heparin anticoagulation. AT activity is reduced by long-term heparin therapy. This prospective, observational study investigated 1516 consecutive cardiac-surgical patients (1304 patients >1 yr (Group A) and 212 patients < or = 1 yr (Group I)). AT activity was measured the day before surgery by a chromogenic substrate assay. The celite-activated activated clotting time (ACT) was used to guide intraoperative heparin administration. Heparin sensitivity was calculated and the postoperative blood loss and perioperative blood requirement was recorded. Infant patients had significantly less preoperative AT activity compared with older patients: 84 (33)% vs 97 (17)%, median (interquartile range) (P < 0. 05). The subgroup of patients aged <1 mo (n = 64) demonstrated a preoperative AT activity of 56 (27)% as compared with 90 (23)% in infant patients between one month and one year (n = 148). In adult patients, preoperative AT activity depended predominantly on preoperative heparin treatment: 62% of the patients with an AT activity <80% were pretreated with heparin. Five minutes after heparin but before CPB the ACT was 587 (334) s in Group A patients with AT activity > or = 80%, and 516 (232) in patients with AT activity < or = 80% (P < 0.05). The target ACT of 480 s was achieved in 70% of patients with normal AT activity in Group A compared with only 54% of patients with AT activity <80% (P < 0.05). In Group A patients with decreased AT activity, 18% demonstrated an inadequate ACT response-defined as ACT <400 s-to the first bolus injection of heparin. In Group I, preoperative AT activity did not influence the ACT response (ACT 5 min after heparin: 846 [447] s in patients with AT activity > or = 80% vs 1000 [364] s in patients with decreased AT activity). The heparin sensitivity was 2.4 (1.1) s/unit heparin/kg compared with 1.5 (0.8) s/unit heparin/KG in group A (P < 0.05). These results suggest that preoperative diminished AT activity causes reduced response to heparin in adult but not in infant patients. Infant patients demonstrate a higher heparin sensitivity despite lower preoperative AT activity. Measurement of preoperative AT activity identifies adult patients at risk of reduced sensitivity to heparin. IMPLICATIONS: In patients less than one year of age, low antithrombin (AT) activity is caused by the immature coagulation system. Despite low AT activity, these young patients demonstrate a normal or increased response to heparin anticoagulation before cardiopulmonary bypass (CPB). In contrast, in patients older than one year of age and adult patients decreased preoperative AT activity is mainly caused by preoperative heparin therapy and causes insufficient response to heparin anticoagulation with a standard heparin dosage. Measurement of preoperative AT activity identifies patients at risk of inadequate anticoagulation during CPB.

Reduction of pro-inflammatory cytokine levels and cellular adhesion in CABG procedures with separated pulmonary and systemic extracorporeal circulation without an oxygenator.

OBJECTIVE: We have recently shown that a considerable amount of pro-inflammatory cytokines is released during pulmonary passage after aortic declamping in patients undergoing coronary artery bypass grafting. The present study was performed to investigate whether bilateral extracorporeal circulation with the lungs as oxygenators can reduce the inflammatory responses of the lungs. METHODS: Eighteen consecutive patients undergoing coronary artery bypass grafting were randomly assigned to routine extracorporeal circulation with cannulation of right atrium and aorta (routine circulation, ten patients) or to a bilateral extracorporeal circulation with additional cannulation of left atrium and pulmonary artery (bilateral circulation, eight patients). Blood was simultaneously drawn from right atrium and pulmonary vein at 1, 10 and 20 min reperfusion. The levels of interleukin (IL)-6 and IL-8 and the adhesion molecules CD41 and CD62 on platelets and CD11b and CD41 on leukocytes were determined. Because of considerable interindividual scatter, the pulmonary venous levels are normalized to percent of the respective right atrial value at each time point. RESULTS: At 1 min reperfusion pulmonary venous levels of IL-6 and IL-8 in routine circulation were +44+/-15% and +43+/-28% of the respective right atrial values. The respective values in bilateral circulation were -3+/-4% and -6+/-7% (P=0.02 and P=0.05 vs. respective right atrium). Similar increments were found after 10 and 20 min. Platelet-monocyte coaggregates were retained during pulmonary passage at 1 min reperfusion in routine circulation (-21+/-6%), but washed out in bilateral circulation (+5+/-8%, P=0. 007). At 20 min reperfusion, activated polymorphonuclear neutrophils (PMN) were retained in routine circulation (-16+/-9%) but washed out in bilateral circulation (+19+/-29%, P=0.05; all data given as mean+/-SEM). CONCLUSIONS: Bilateral extracorporeal circulation without an artificial oxygenator significantly reduces the inflammatory responses during pulmonary passage after aortic declamping.

Three-dimensional clinical PET in lung cancer: validation and practical strategies.

UNLABELLED: The feasibility of 3-dimensional acquisition mode for semiquantitative analysis in thoracic PET studies was compared to the conventional 2-dimensional mode. Several practical considerations were analyzed to propose an optimized scanning protocol for clinical use. METHODS: Twenty-one patients with focal thoracic abnormalities were evaluated with FDG PET. The acquisition consisted of 3 consecutive static scans for a single bed position: 3-dimensional (10 min), 2-dimensional (15 min), and 3-dimensional (5 min). On the basis of the average and maximum activity values per region of interest, standardized uptake value (SUV) normalized for total body weight (TBW), lean body mass (LBM), body surface area (BSA), and blood glucose level (PGL) were evaluated. The effect of the delay between tracer injection and PET scanning on the SUV, as well as on the relative error of the activity distribution, was studied from 40-134 min after tracer injection. RESULTS: A strong positive correlation was observed among SUVs from 2-dimensional and both 3-dimensional acquisitions. The mean SUV percentage differences between both acquisition modes were about 17%, differences that were not statistically significant when time postinjection was addressed in the analysis of covariance. SUVs provided the greatest variability and differences among studies on experimental periods up to 70 min postinjection. Indeed, the variability of 20% observed on the SUVs from 2 PET scans 13 min apart was reduced to 9% when the acquisitions started at least 70 min after tracer injection. In addition, a two-fold reduction in the relative error of the activity distribution was observed over this period of time. The reproducibility coefficient was increased from 0.87 to 0.95 before and after 70 min postinjection, respectively. No correlation was found between different normalization procedures of SUV and LBM, BSA, TBW, or height, whereas a weak correlation was found between SUV and PGL. CONCLUSION: 18F-FDG 3-dimensional PET is a realistic alternative to the gold standard 2-dimensional for clinical nonkinetic studies. A short, 5-min 3-dimensional acquisition at 70 min postinjection is proposed as the best protocol for the clinical evaluation of thoracic pathologies.

Drew-Anderson technique attenuates systemic inflammatory response syndrome and improves respiratory function after coronary artery bypass grafting.

BACKGROUND: Cardiopulmonary bypass causes inflammatory reactions leading to organ dysfunction postoperatively. This study was undertaken to determine whether using patients' own lungs as oxygenator in a bilateral circuit (Drew-Anderson Technique) could reduce systemic inflammatory response to cardiopulmonary bypass, improving patients clinical outcome following coronary artery bypass grafting. METHODS: A prospective randomized controlled trial involving 30 patients, divided in two groups of 15 patients each, undergoing elective coronary artery bypass grafting, was undertaken. In the Drew-group bilateral extracorporeal circulation using patient's lung as oxygenator was performed. The other patients served as control group, where standard cardiopulmonary bypass procedure was used. RESULTS: Pro-inflammatory and anti-inflammatory mediators were measured. Peak concentrations of proinflammatory interleukin-6, interleukin-8, were significantly lower in 15 patients undergoing Drew-Anderson Technique compared with the concentrations measured in 15 patients treated with standard cardiopulmonary bypass technique. Differences in patient recovery were analyzed with respect to time of intubation, blood loss, intrapulmonary shunting, oxygenation, and respiratory index. In patients undergoing uncomplicated coronary artery bypass grafting procedures bilateral extracorporeal circulation using the patients' own lung as oxygenator provided significant biochemical and clinical benefit in comparison to the standard cardiopulmonary bypass procedure. CONCLUSIONS: This prospective randomized clinical study has demonstrated that exclusion of an artificial oxygenator from cardiopulmonary bypass circuit significantly decreases the activation of inflammatory reaction, and that interventions that attenuate this response may result in more favorable clinical outcome.