[Utility of PET-CT on radiotherapy planning of head and neck cancer. Our initial experience]. / Utilidad de la PET-TAC en la planificación radioterápica en el cáncer de cabeza y cuello. Nuestra experiencia inicial.

OBJECTIVE: To describe the methods used for the incorporation of FDG-PET-CT on radiotherapy planning of patients with head and neck cancer and also to evaluate the impact of FDG-PET-CT on staging and tumor volume definition. MATERIAL AND METHODS: A prospective study in which 20 patients with head and neck tumor submitted for radiotherapy treatment were included. All underwent a whole body PET- CT (GE DSTE 16) for staging and restaging, also acquiring an additional 3h delayed PET image with diagnostic CT parameters for planning. A CT scan with diagnostic protocol, tabletop available for radiotherapy treatment and the same personalized head-shoulder mask were used in the latter. Lymph node involvement and/or distant involvement were evaluated, considering the changes in staging. We also evaluated the differences in volumes obtained between the different techniques. The threshold value used for delineating PET gross tumor volume (GTV) was empirically established and ranged from 20-40% of the maximum SUV. RESULTS: Radiotherapy planning was performed with PET-CT in 20 patients between October 2007 to September 2008. A total of 29 lesions (18 primary lesions because 2 patients were excluded as no tumor was observed on the PET CT images, and 11 nodes). The most frequent location was oropharynx (5 patients). Mean maxSUV of the 29 lesions was 14.4 (range 5.0 and 26.4). No statistically significant differences were found between the GTV PET and GTV CT (mean 21.9cm³ and 19.3cm³, respectively). PET-CT modified the staging in 20% of the patients, with a diagnostic and therapeutic impact of 50 and 25%, respectively. CONCLUSION: The incorporation of PET-CT in routine radiotherapy planning is a promising technique that requires close collaboration between the nuclear medicine and radiotherapy oncology departments. PET-CT achieves better staging in patients and has a significant diagnostic and therapeutic impact. The use of the hybrid technique avoids problems arising from co-registry as well as a second examination for planning with the consequent advantage for the patient. Nonetheless, more prospective and randomized studies with pathology specimens are needed to evaluate the real impact in the tumor volume definition.

[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.

[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.

[(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.

[PET-CT with intravenous contrast in the evaluation of patients with lymphoma. Contribution to diagnostic indications]. / PET-TAC con contraste intravenoso en la valoración de pacientes con linfoma. Aproximación hacia las indicaciones diagnósticas.

AIM: To define the utility of intravenous contrast administration in the PET-CT (PET-CTc) in patients with lymphoma in order to determine its possible indications. MATERIAL AND METHODS: 78 patients with lymphoma were prospectively evaluated. All underwent simultaneous PET-CTc scans in a hybrid system for staging (8), evaluation of response to treatment (29), suspicion of recurrence (9) and complete remission control (48). The PET scan was acquired by a conventional method and the diagnostic CT scan was performed according to radiological protocol. Both examinations were evaluated blinded and independently, analyzing 28 anatomical locations in order to determine the degree of agreement. Final diagnosis was established by the clinician based on the histological study, results of other diagnostic techniques or clinical follow-up. RESULTS: The final result of both techniques were concordant in 87/94 studies (92.5%). A total of 158 (36 FP) pathological locations were detected with PET-CT and 189 (71 FP) with CTc, with 72 locations being discordant between both techniques. Global sensitivity, specificity, PPV and NPV were 93%, 98%, 77% and 99%; and 94%, 97%, 62% and 99%, respectively. CONCLUSIONS: Administration of intravenous contrast does not seem to provide any advantage in the determination of nodal and extranodal disease in lymphoma patients. The low prevalence of disease probably accounts for the limited PPV of both techniques. An increase of our sample size, with a greater homogeneity of the groups, should offer more reliable results.

[Positron emission tomography with 18F-fluorodeoxyglucose in patients with uterine sarcoma]. / Tomografía por emisión de positrones con 18F-fluordesoxiglucosa en pacientes con sarcoma uterino.

OBJECTIVE: Describe our experience with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), in patients with uterine sarcomas, under suspicion of recurrence and in tumour staging after hysterectomy as an incidental pathology finding. MATERIAL AND METHODS: A retrospective review, between april 2002 and january 2006, of FDG-PET performed in 10 patients with clinical diagnosis of uterine sarcoma was made (7 patients under recurrence suspicion and three under initial staging). Mean age was 52.2 yrs. Evolution time after initial diagnosis vary from one month to 15 yrs (median time: 14 months). Lesions were classified as 8 leiomyosarcomas and 2 carcinosarcomas. FIGO staging were establish resulting 5 patients stage I, 1 patient stage III, and 4 patients stage IV. RESULTS: 4 of 7 patients under suspicion of recurrence showed discrepancies between positron emission tomography (PET) and conventional imaging techniques (CIT) information. FDG-PET was negative in three cases of non-conclusive CT. PET was negative in one case with pulmonary metastases. The 3 staging studies were concordant both FDG-PET and CIT images. Pathological information was obtained in 5 cases, and a mean time of 14 months of clinical follow up was made. CONCLUSIONS: FDG-PET can be useful in the follow up of uterine sarcoma patients, and also when it is an incidental finding in other causes hysterectomy.

18F-FDG PET/CT as predictor of tumour biology and prognosis in epithelial ovarian carcinoma. / PET/TC con 18F-FDG como predictor de la biología tumoral y del pronóstico en el cáncer epitelial ovárico.

OBJECTIVE: To investigate the relationship between maximum standardised uptake value (SUVmax) of ovarian lesions and histopathology subtypes, and their involvement in the response and prognosis of patients with epithelial ovarian carcinoma (EOC). MATERIAL AND METHODS: A retrospective analysis of 31 patients with EOC and 18F-FDG-PET/CT before treatment, including an assessment of the SUVmax of ovarian lesion. Histopathological diagnosis and follow-up was performed. A study was made on the relationship between the SUVmax and histological type (type I and II) and tumour stage, as well as the role of various parameters (SUVmax, histology, stage) on the patient outcomes (complete response [CR], overall survival [OS], disease-free survival [DFS], and disease-free [DF] status, at 12 and 24 months). RESULTS: The medium SUVmax in type I lesions was lower than in type II (6.3 and 9.3, respectively; P=.03). A 7.1 cut-off was set for SUVmax in order to identify type II EOC (sensitivity: 77.8%, specificity: 69.2%; AUC=0.748; P=.02). No significant relationship was found between tumour stage and SUVmax. CR was more common in early stages; relative risk (RR) of 1.64; P=.003, as well as in type I tumours and a lower SUVmax. Tumour stage was decisive in DFS (P=.04), LE24m (0.07) and OS (P=.08). Longer DFS and a higher percentage of DF 24m were observed in type I tumours (RR: 1.32; P=.26). CONCLUSIONS: SUVmax was related to EOC histology, so could predict the response and prognosis of these patients. No association was found between glycolytic activity of the primary tumor with the response and prognosis.

[Positron emission tomography with fluordesoxyglucose-F18 in follow-up of endometrial cancer]. / Tomografía de emisión de positrones con fluordesoxiglucosa-F18 en el seguimiento del cáncer de endometrio.

OBJECTIVE: To assess the utility of FDG-PET in the follow-up of patients treated for endometrial cancer and with suspicion of recurrence according to conventional imaging methods (CT, MRI) and/or elevation of serum tumour markers. MATERIALS AND METHODS: Between April 2002 and December 2005, eleven patients underwent 17 FDG-PET studies (six with 2 studies); mean age was 63.4 yrs (range, 52-69 yrs) and time since diagnosis ranged from 11 months to 12 yrs (mean of 56 months). Initially, seven patients were in stage I, three in stage III and one in stage IV (FIGO classification). Histologically, they corresponded to 8 endometrioid carcinomas and 3 non endometrioid carcinomas. RESULTS: FDG-PET showed infradiaphragmatic uptake in 3 patients and disseminated disease in 7 cases. FDG-PET showed no uptake in one patient. CT (n = 7) or MRI (n = 7) detected infradiaphragmatic lesions in 5 patients and visceral lesions in 2. In 11 patients, tumour markers were elevated (CA125, n = 9; CA19.9, n = 2; CA15.3, n = 2). In 7 patients, FDG-PET modified the information yielded by conventional imaging techniques and in 4 patients, the FDG-PET contributed no additional information. In 2 patients, histologic confirmation of the lesions was obtained and in 9 patients, there were clinical follow-up (from 3 to 20 months, mean of 8.7 months) and imaging studies. CONCLUSIONS: FDG-PET is superior to CT and MRI for detecting recurrences in the follow-up of patients with endometrial cancer.

[Progressive myositis ossificans. Utility of bone scintigraphy]. / Miositis osificante progresiva. Utilidad de la gammagrafía ósea.

47 year old woman affected by myositis ossificans, with muscular calcifications in her evolution. Bone scintigraphy showed increased polyfocal activity as well as uptake of different intensity in soft tissues. The bone scintigraphy allows for early identification of ossification areas in soft tissues, as it can even detect injuries earlier than that observed with other image techniques. It is considered to be very useful in the diagnosis and establishment of the extension of the process, as well as follow-up.

[Value of thallium 201-SPECT in typing brain space-occupying lesions]. / Valor de la SPECT con Talio-201 en la tipificación de lesiones ocupantes de espacio intracerebrales.

OBJECTIVE: This study was designed to assess the diagnostic accuracy of single photon emission computed tomography with Tl-201 (SPECT Tl-201) to establish the tumoral or non-tumoral nature of brain space occupying lesions in comparison with usual diagnostic techniques. MATERIAL AND METHODS: The study population consisted of 37 patients, 24 men (64.9 %) and 13 women (35.1 %), mean age 48 +/- 16 years. After establishing the clinical and radiological diagnosis of brain lesion, all patients underwent SPECT Tl-201, evaluating it only by subjective analysis and blinded to neuroestructural techniques. After surgical resection all patients were evaluated anatomopathologically to establish the histologic nature. RESULTS: The sensitivity of SPECT Tl-201 (0.87) was higher than standard neuroimaging techniques (0.78). Specificity (0.43), positive (0.87) and negative (0.43) predictive values of SPECT were similar to neuroestructural procedures (MRI and CT scan) with 0.43, 0.82 and 0.38 values. Tumoral disease prevalence was 0.81. Neuroestructural procedures were non-conclusive in 18.9 % of the studies. No non-conclusive results were obtained with SPECT Tl-201. CONCLUSIONS: SPECT Tl-201 is a diagnostic procedure of high sensitivity to establish the tumoral nature of brain lesions, with poor specificity, similar to structural X-ray techniques.

[Quality control dose calibrators]. / Control de calidad de activímetros.

We have reviewed the legislation about the quality control of dose calibrator. The importance of verifying the correct work of these instruments, is fundamental in daily practice of radiopharmacy and nuclear medicine. The Spanish legislation establishes to include these controls as part of the quality control of radiopharmaceuticals, and the program of quality assurance in nuclear medicine. We have reviewed guides and protocols from international eminent organizations, summarizing the recommended tests and periodicity of them.

[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.

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.

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.