[Quantitative and qualitative evaluation of the interim PET/CT in lymphoma treatment in the prediction of complete metabolic response]. / Evaluación cuantitativa y cualitativa de la PET/TC a mitad del tratamiento en linfomas en la predicción de respuesta metabólica completa.

OBJECTIVE: To compare two different methods for the interpretation of interim PET/CT (PET/CT-i) in lymphomas, and to establish which one best predicts a complete metabolic response (CMR) in the PET/CT study at the end of treatment (PET/CT-et). MATERIAL AND METHODS: Retrospective longitudinal analysis of the PET/CT studies for staging (PET/CT-s), PET/CT-i and PET/CT-et of 65 patients, 35 Hodgkin's lymphoma (HL) and 30 Non-HL. The PET/CT-i was performed between the second and fourth chemotherapy cycle. It was interpreted using two different criteria: qualitative criteria (5 point visual scale), semiquantitative criteria (percentage difference between the lesion with more SUVmax in the PET/CT-s and PET/CT-i). We analyzed the likelihood of obtaining a CMR in the PET/CT-et according to the results obtained on the PET/CT-i with these two criteria. RESULTS: We obtained sensitivity (S), specificity (Sp), positive predictive values (PPV), negative predictive values (NPV) and likelihood ratio (LR) for the qualitative/semiquantitative method of 91%/80%, 76.2%/67%, 88.9%/83.3%, 80%/60.9% and 32%/7.8%, respectively, to predict a CMR in the PET/CT-et. There were no statistically significant differences between the LR of both methods (p=0.1942). CONCLUSION: We found clear differences in S, Sp, PPV and NPV between both interpretation criteria for the PET/CT-i to predict a CMR in the PET/CT-et. Nevertheless, we cannot confirm the superiority of the qualitative method over the semiqualitative method for this purpose as no statistically significance differences were found in their LR in our study.

Positron emission tomography/computed tomography exam request form under review. Is it effective?

AIM: Our objective was to analyze all the rejected PET/CT-request forms (rf), its primary question to be answered and the impact of not performing the PET/CT studies for the management of the patients. MATERIAL AND METHODS: We retrospectively reviewed all the cancelled PET/CT-rf received in our department from January 2007 to June 2011. The reasons for cancelling were patient clinical status, request from referring physician, patient request and criteria of nuclear medicine physician. PET/CT-rf were classified according to the primary question to be answered. The clinical evolution of patients was followed up for 6 months after PET/CT was requested. RESULTS: Thirty-nine studies were cancelled due to the patient clinical situation (mainly advanced state of neoplastic disease), 46 due to request from referring physician, 18 by patient request and 74 PET/CT-rf were rejected due to nuclear medicine physician criteria. Thirty-four patients with a rejected PET/CT had known neoplastic history. The more prevalent primary questions to be answered were: evaluation of pulmonary (20) and bone lesions (13). Regarding pulmonary nodules, only 4 patients had previous neoplastic disease and their size was less than 5mm. The rejection of PET/CT studies did not cause any impact in the natural evolution of the disease of the patients. CONCLUSION: This procedure avoided unnecessary PET/CT scans reducing expenses and radiation without any detriment in the patients.

[Implementation of a quality management system according to the UNE-UN-ISO 9001:2008 standard in a nuclear medicine department]. / Implantación de un sistema de gestión de calidad según norma UNE-UN-ISO 9001:2008 en un servicio de medicina nuclear.

OBJECTIVE: To describe the process of implementing a quality management system according to UNE-EN-ISO 9001:2008 standard in a Nuclear Medicine Department. MATERIAL AND METHOD: In February 2008, the committee on internal quality of the Department was established, naming a responsible physician. The general operating plan was drawn up, following the requirements established by the ISO 9001:2008 standard. It defined the scope of the standard, defining, preparing and transcribing the various activities of our Department. Four training sessions were carried out. RESULTS: A total of nine general and two specific procedures were documented in which all the activities performed in our Department were included. Personnel records of each worker were created, including their profiles and training plan. A record of the equipment and service providers was created, as well as issues with the latter. Satisfaction surveys were obtained from external (patients) and internal customers (faculty applicants). Targets for improvement and activity markers were established. Two audits were performed to complete the process, one internal and one external. The Department was accredited in April 2010. CONCLUSION: The quality accreditation process is a tool that requires reflection on how we do things and how they can be improved. It makes it possible to measure what we do, to analyze and introduce improvement measures, and therefore, to achieve a higher level of quality in the service we provide our customers. The involvement of the Department workers with a commitment to team performance was essential.

Study of the sentinel node in endometrial cancer at early stages: preliminary results.

AIM: To investigate the applicability of the sentinel lymph node biopsy technique in early stages of endometrial cancer. MATERIAL AND METHODS: A prospective study that included consecutive patients with a histological diagnosis of clinical state I endometrial carcinoma was performed. Two doses of 2 mCi (74 MBq) of (99m)Tc-albumin nanocolloid were injected in the uterine cervix, and planar and SPECT-CT images were obtained at one hour, and at 24 hours if no migration of the tracer was observed. Methylene blue dye was also injected into the cervix immediately prior to the surgery. A gamma probe was used during the surgical procedure for sentinel lymph node identification. In all cases, a hysterectomy, double adnexectomy and pelvic lymphadenectomy were performed, carrying out a histological analysis (hematoxylin-eosin) of the sentinel lymph nodes and the lymphadenectomy specimen. RESULTS: We included 19 patients, with a final diagnoses of endometrioid carcinoma (18 cases) and endometrial stromal sarcoma (1 case). At least one sentinel lymph node was identified in 17 of them (89.5% detection rate). Twenty-nine sentinel lymph nodes were identified during surgery, all of them negative for neoplastic infiltration. No metastatic invasion was found in the pelvic lymphadenectomy specimens as well. CONCLUSIONS: The sentinel lymph node biopsy technique seems to be a reliable tool in nodal staging of endometrial cancer at early stages, with an acceptable detection rate and high histological correlation. The low prevalence of lymphatic spread in this group of patients and the encouraging results obtained could make the sentinel lymph node an alternative to routine complete lymphadenectomy.

18F-FDG semi-quantitative parameters and biological prognostic factors in locally advanced breast cancer.

AIM: To analyse the correlation between (18)F-FDG uptake assessed by PET/CT in locally advanced breast tumours and histopathological and immunohistochemical prognostic factors. MATERIAL AND METHODS: Thirty-six women with breast cancer were prospectively evaluated. PET/CT was requested in the initial staging previous to adjuvant chemotherapy (multicentric study). All the patients underwent an (18)F-FDG PET/CT with a dual-time-point acquisition. Both examinations were evaluated qualitatively and semiquantitatively with calculation of SUVmax values in PET-1 (SUV-1) and in PET-2 (SUV-2) and the percentage variation of the standard uptake values (retention index) between PET-1 and PET-2. Clinical and metabolic stages were assessed according to TNM classification. The biological prognostic parameters, such as the steroid receptor status, p53 and c-erbB-2 expression, proliferation rate (Ki-67), and grading were determined from tissue of the primary tumour. Metabolic and biological parameters were correlated. RESULTS: A positive relationship was found between semiquantitative metabolic parameters and biological parameters. SUV-1 and SUV-2 values did not show significant statistical correlation (p<.05) except for the clinical tumour size. About the biological parameters, retention index showed the best results with positive and significant relation (p<.05) with estrogen and progesterone receptor status and Ki-67. Isolated SUV values did not show significant relation to these parameters. CONCLUSION: Retention index showed the best relation with biological parameters compared to isolated SUVmax values. These data suggest that SUV change over time is a prognostic marker.

Is a selective brain (18)F-FDG PET/CT study profitable in patients with small cell lung cancer?

AIM: To evaluate the diagnostic yield of a selective brain (18)F-FDG PET/CT in neurologically asymptomatic patients with small cell lung cancer. MATERIAL AND METHODS: Twenty-one neurologically asymptomatic patients referred to our service between July 2008 and December 2009 for staging of small cell lung cancer were included in the study. All underwent a standard (18)F-FDG PET/CT study followed by a selective brain PET/CT. The neurological findings were confirmed by CT scan with intravenous contrast, MRI or minimum clinical follow-up of 6 months. The brain PET/CT was considered positive if any alteration was observed in the FDG distribution that was not related with previously known benign lesion in the CT image. RESULTS: Brain metastases were detected in 5 of the 21 patients (23.8%), these being correctly classified in 3 of them by the selective brain PET/CT. The stage was upgraded in one of them with the selective brain study. Only one patient showed a hypermetabolic lesion in the PET images in relationship to the lesions observed in the CT images. Sensibility, specificity, positive predictive value and negative predictive value were 60, 100, 100 and 88.89%, respectively. CONCLUSION: Hypometabolic areas in the cerebral parenchyma are frequently associated to metastatic lesions in patients with small cell lung cancer. The selective brain PET/CT in these patients allows correct staging and early treatment of unsuspected metastasis.

[Prevalence of micrometastases and isolated tumor cells in the sentinel node at early stage breast cancer]. / Prevalencia de micrometástasis y células aisladas en el ganglio centinela en estadios iniciales del cáncer de mama.

AIM: To analyze the prevalence of isolated tumor cells (ITC) and micrometastases in the sentinel node of early stage breast cancer. MATERIAL AND METHODS: A total of 234 patients diagnosed of breast cancer, stages T1 or T2, with no axillary involvement detected by palpation or ultrasound-FNA, were studied. The sentinel node (SN) was identified by lymphoscintigraphy and removed in the operating room. Serial sections and immunohistochemical staining were then performed, classifying them as negative (SN-), negative with ITC (SN-ITC), positive with micrometastases (SN+mic) and positive with macrometastases (SN+mac). A complete axillary lymphadenectomy (CAL) was carried out in those cases with micro- or macrometastases, the former being classified as negative (CAL-), positive with micrometatases (CAL+mic), and positive with macrometastases (CAL+mac). The follow-up ranged from 6-71 months. RESULTS: ITC were found in 12 patients (5.1%) and micrometastases in 24 (10.3%). Thus, a total of 36 patients were affected by some of these conditions (15.4%). In the group with micrometastases, the result of CAL was CAL- in 19/24 (79.1%), CAL+mic in 2 (8.3%) and CAL+mac in 3 (12.5%). No axillary recurrences have occurred up to date. CONCLUSIONS: ITC and micrometastases were found in the sentinel node in a significant percentage of patients in the early stages of breast cancer. The low percentage of further axillary invasion in the group of micrometastases may open up the possibility of avoiding CAL in favor of other adjuvant treatments (chemotherapy, radiotherapy).

18F-FDG-PET/CT in the surveillance of patients with lymphoma: detection of asymptomatic recurrences.

AIM: To assess the diagnostic accuracy of (18)F-FDG-PET/CT in detecting asymptomatic recurrences in patients with lymphoma. To define uptake patterns of recurrence indicative of recurrence. MATERIAL AND METHODS: Those patients with lymphoma who fulfilled the following inclusion criteria of clinical complete remission and negative PET/CT study were included retrospectively and longitudinally. Conventional surveillance of these patients was performed only by (18)F-FDG PET/CT following a standardized procedure. Pathologic locations (supra- and infradiaphragmatic) and their character (single or multiple) were analyzed in order to determine reliable metabolic patterns of recurrence. The final diagnosis was established by histopathological analysis or clinical follow-up greater than 8 months. RESULTS: A total of 199 explorations belonging to 106 patients with lymphoma were included. Of these patients, 59 had Hodgkin's lymphoma and 47 non-Hodgkin's lymphoma. There was suspicion of relapse from the metabolic point of view in 27 of the PET/CT scans. Of these, 14 (10 patients) were false positive (FP), and 13 (8 patients) true positive. The remaining studies were true negative, no false negatives being detected. The pattern most frequently related to recurrence was infradiaphragmatic lymph node involvement while most of the FP had isolated supradiaphragmatic involvement. Sensitivity, specificity, PPV, NPV and diagnostic accuracy of PET/CT parameters for the study were 100%, 92%, 48%, 100% and 93%, respectively. CONCLUSION: (18)F-FDG-PET/CT is a sensitive technique in the detection of asymptomatic recurrences in patients with lymphoma during their follow-up. Multiple character and infradiaphragmatic locations were the patterns that best correlated to the diagnosis of recurrence.

[18F-FDG PET/CT with retrograde filling of the urinary bladder in the assessment of malignant pelvic disease]. / PET-TAC con (18)F-FDG tras llenado retrógrado vesical en el estudio de patología pélvica maligna.

AIM: To assess the role of PET/CT with retrograde filling of urinary bladder (RFUB) in the assessment of pelvic malignancy in patients with urothelial or gynecological tumors. MATERIAL AND METHODS: A retrospective longitudinal analysis based on 62 studies belonging to 52 patients was performed. All of them had a history of pelvic malignancy (29 urothelial and 23 gynecological) and 42 had undergone previous treatments. All patients underwent a standard PET/CT protocol. Inclusion criteria were radiological alterations in pelvic organs or increased urinary activity of (18)F-FDG that hindered evaluation of the pelvic structures. Pathological pelvic locations were assessed as the additional value of PET/CT with RFUB. The pathologic lesions were histologically or clinically evaluated with a minimum follow-up of 12 months. RESULTS: Pelvic malignancy was confirmed in 33 cases, 16 of which were of urothelial origin. A total of 35/62 studies showed a pathologic PET/CT in pelvis, 4 of them were false positive and 2 false negative. In 19 cases, malignancy was detected in the bladder wall, 16 of which were true positive. No false negative was detected. Regarding standard imaging acquisition, RFUB helped to confirm or rule out bladder and/or gynecological disease in 54 cases. CONCLUSION: Retrograde bladder filling is a highly recommended technique in the assessment of malignant pelvic disease, especially of bladder origin.

[Micrometastasis in the sentinel node and axillary lymph node macro-metastasis in breast cancer]. / Micrometástasis en el ganglio centinela y macrometástasis ganglionares axilares en el cáncer de mama.

AIM: The study of the sentinel node has made it possible to obtain more comprehensive knowledge about the extent of axillary involvement in breast cancer. It has also decreased the surgical morbidity associated to the surgical examination of the axilla. The systematic use of immunohistochemical staining and molecular biology techniques improves the ability to detect the presence of micrometastasis or isolated tumor cells in a significant number of cases when this is the only sign of the lymph node extension of the disease. The possibility of avoiding complete axillary lymphadenectomy in those patients who are only affected by micrometastasis is proposed because of the low incidence of further involvement of the remaining lymph nodes. MATERIAL AND METHOD: 159 patients diagnosed of stage T1 or T2 breast cancer, in which the sentinel node had been identified by scintigraphy and intraoperative localization, were included in the study. Complete axillary lymphadenectomy was performed when micro- or macrometastases were found in the sentinel node, in order to determine the degree of axillary involvement. RESULTS: A total of 40 patients (25%) showed infiltration of the sentinel node. This infiltration was only by micrometastasis in 17 of them (10.7%). Of these 17 patients, only 2 (11.8%) showed macro-metastasis in the lymphadenectomy. In the remaining subjects, the final staging reached after the sentinel node study was not modified. CONCLUSION: It is possible to speculate that, in the future, axillary dissection can be avoided in those patients diagnosed of micrometastasis in the sentinel node, pending the conclusions of the on-going multicenter studies.

[Diagnostic and therapeutic impact of 18F-FDG-PET/CT in patients with suspected breast cancer recurrence]. / Impacto diagnóstico y terapéutico de la (18)F-FDG-PET/TAC en pacientes con sospecha de recidiva de cáncer de mama.

Breast cancer is a tumor with high prevalence in our environment. Thus, it is essential to make an early diagnosis in both the primary disease and its recurrence, given the high mortality of the cases with the advanced disease. Our study has aimed to evaluate the impact of (18)F-FDG-PET/CT in patients with suspected breast cancer recurrence and their therapeutic management. This study analyzed the PET/CT of 70 patients with a background of breast cancer and suspicion of recurrence, either because of elevation of tumor markers (n=28), doubtful findings on other imaging techniques (n=56) and/or suspicious symptoms (n=1). All the patients underwent a standard FDG-PET study acquired in combination with low-dose CT. The studies were considered pathological in 34 of the 70 patients, with 29 true positive, 32 true negative, 5 false positive and 4 false negative results. The final diagnosis was established either by histopathologic confirmation (n=17), other imaging techniques (n=26) and/or clinical radiological follow-up (n=27, mean 12.7 months). The sensitivity, specificity, positive predictive value and negative predictive values obtained were 87.8%, 86.4%, 85.2% and 88.8%, respectively. Therapeutic management was modified in 41% of the patients. In conclusion, PET/CT is a technique with high diagnostic yield in patients with suspected breast cancer recurrence.

(18)F-FDG PET-CT respiratory gating in characterization of pulmonary lesions: approximation towards clinical indications.

AIM: To evaluate the effect of the 18F-FDG PET-CT respiratory gating (4D) study in the correct documentation of pulmonary lesions with faint uptake in standard PET-CT. METHODS: Forty-two pulmonary lesions with a low or no detectable uptake of FDG (SUV(max) < 2.5) in 3D PET-CT were prospectively evaluated in 28 patients (19 males and 9 females), mean age 66.5 years (41-81). 22 patients had neoplastic background. A conventional PET-CT (3D) total body scan was performed approximately 60 min after iv injection of a mean dose of 370 MBq. Furthermore, a 4D PET-CT (synchronized with respiratory movement) thorax study was acquired. SUV(max) was determined for each lesion in both studies. For the 4D studies, we selected the SUV(max) in respiratory period with the highest uptake ("best bin"). We calculated the SUV(max) percentage difference between 3D and 4D PET-CT (% difference = SUV(max) 4D - SUV(max) 3D/SUV(max) 3D x 100) and the relation of this value with the size and locations of the lesions. In 4D study, any lesion with SUV(max) > or = 2.5 was classified as malignant. We assessed the changes of lesion classification (from benign to malignant) applying the 4D technique. The final diagnosis was obtained by histological assessment or clinical and radiological follow-up longer than 12 months. RESULTS: Forty out of 42 lesions showed an increase of SUV(max) in the 4D study with respect to 3D. The mean SUV(max) in the 3D and 4D PET-CT studies were 1.33 (+/-0.59) and 2.26 (+/-0.87), respectively. The SUV(max) percentage difference mean between both techniques was 83.3% (+/-80.81).The smaller the lesion the greater was the SUV(max) percentage difference (P < 0.05). No differences were observed depending on the location of the lesion. In 40% of cases, there was a change in the final classification of lesions from benign to malignant. In the final diagnosis, 24 lesions were malignant. 4D PET-CT diagnosed correctly the 52% of them. CONCLUSIONS: The 4D PET-CT study permitted a better characterization of malignant lung lesions compared with the standard PET-CT, because of its higher sensitivity. 4D PET-CT is a recommendable technique in the early diagnosis of malignant lesions.

[(18)F-FDG PET-CT and respiratory synchronization: effect in the detection and catalogation of pulmonary lesions]. / (18)F-FDG PET-TAC y sincronización respiratoria: efecto en la detección y catalogación de lesiones pulmonares.

UNLABELLED: The respiratory movement reduces the sensitivity in the detection of pulmonary lesions. The synchronized acquisition of PET with respiratory movement (4D) can reduce this inconvenient. Our objective was assess the effect of 4D PET-CT in the metabolic activity of (18)F FDG and final classification of pulmonary lesions. MATERIAL AND METHODS: 12 patients with 18 pulmonary lesions with sizes within 0.8-4cm were assessed. The maximum SUV was obtained in the imaging acquired in standard conditions (3D) and the obtained in the respiratory period with higher metabolic activity in 4D images. The difference of percentage between both values was calculated. Moreover were evaluated the changes of the classification of pulmonary nodes (benign or malignant) obtained from the assessment of 4D and 3D PET images. RESULTS: 17/18 pulmonary lesions showed an increase in the SUV(max) value in the 4D with respect to 3D image. 5 lesions showed SUV(max) values >2.5 in 4D image and <2.5 in 3D image. From these 3 were correctly catalogued as malignant with 4D although the number of false positive increased to 2. CONCLUSION: (18)F-FDG 4D PET-CT shows values of metabolic activity more realistic allowing the correct classification reducing the false negative although increasing the false positive.