Economic evaluations of radioembolization with yttrium-90 microspheres in liver metastases of colorectal cancer: a systematic review.

BACKGROUND: Transarterial radioembolization with yttrium-90 (Y-90 TARE) microspheres therapy has demonstrated positive clinical benefits for the treatment of liver metastases from colorectal cancer (lmCRC). This study aims to conduct a systematic review of the available economic evaluations of Y-90 TARE for lmCRC. METHODS: English and Spanish publications were identified from PubMed, Embase, Cochrane, MEDES health technology assessment agencies, and scientific congress databases published up to May 2021. The inclusion criteria considered only economic evaluations; thus, other types of studies were excluded. Purchasing-power-parity exchange rates for the year 2020 ($US PPP) were applied for cost harmonisation. RESULTS: From 423 records screened, seven economic evaluations (2 cost-analyses [CA] and 5 cost-utility-analyses [CUA]) were included (6 European and 1 USA). All included studies (n = 7) were evaluated from a payer and the social perspective (n = 1). Included studies evaluated patients with unresectable liver-predominant metastases of CRC, refractory to chemotherapy (n = 6), or chemotherapy-naïve (n = 1). Y-90 TARE was compared to best supportive care (BSC) (n = 4), an association of folinic acid, fluorouracil and oxaliplatin (FOLFOX) (n = 1), and hepatic artery infusion (HAI) (n = 2). Y-90 TARE increased life-years gained (LYG) versus BSC (1.12 and 1.35 LYG) and versus HAI (0.37 LYG). Y-90 TARE increased the quality-adjusted-life-year (QALY) versus BSC (0.81 and 0.83 QALY) and versus HAI (0.35 QALY). When considering a lifetime horizon, Y-90 TARE reported incremental cost compared to BSC (range 19,225 to 25,320 $US PPP) and versus HAI (14,307 $US PPP). Y-90 TARE reported incremental cost-utility ratios (ICURs) between 23,875 $US PPP/QALY to 31,185 $US PPP/QALY. The probability of Y-90 TARE being cost-effective at £ 30,000/QALY threshold was between 56% and 57%. CONCLUSIONS: Our review highlights that Y-90 TARE could be a cost-effective therapy either as a monotherapy or when combined with systemic therapy for treating ImCRC. However, despite the current clinical evidence on Y-90 TARE in the treatment of ImCRC, the global economic evaluation reported for Y-90 TARE in ImCRC is limited (n = 7), therefore, we recommend future economic evaluations on Y-90 TARE versus alternative options in treating ImCRC from the societal perspective.

Economic evaluations of radioembolization with Itrium-90 microspheres in hepatocellular carcinoma: a systematic review.

BACKGROUND: Transarterial radioembolization (TARE) with yttrium-90 microspheres is a clinically effective therapy for hepatocellular carcinoma (HCC) treatment. This study aimed to perform a systematic review of the available economic evaluations of TARE for the treatment of HCC. METHODS: The Preferred Reported Items for Systematic reviews and Meta-Analyses guidelines was followed by applying a search strategy across six databases. All studies identified as economic evaluations with TARE for HCC treatment in English or Spanish language were considered. Costs were adjusted using the 2020 US dollars based on purchasing-power-parity ($US PPP). RESULTS: Among 423 records screened, 20 studies (6 cost-analyses, 3 budget-impact-analyses, 2 cost-effectiveness-analyses, 8 cost-utility-analyses, and 1 cost-minimization analysis) met the pre-defined criteria for inclusion. Thirteen studies were published from the European perspective, six from the United States, and one from the Canadian perspectives. The assessed populations included early- (n = 4), and intermediate-advanced-stages patients (n = 15). Included studies were evaluated from a payer perspective (n = 20) and included both payer and social perspective (n = 2). TARE was compared with transarterial chemoembolization (TACE) in nine studies or sorafenib (n = 11). The life-years gained (LYG) differed by comparator: TARE versus TACE (range: 1.3 to 3.1), and TARE versus sorafenib (range: 1.1 to 2.53). Of the 20 studies, TARE was associated with lower treatment costs in ten studies. The cost of TARE treatment varied widely according to Barcelona Clinic Liver Cancer (BCLC) staging system and ranged from 1311 $US PPP/month (BCLC-A) to 71,890 $US PPP/5-years time horizon (BCLC-C). The incremental cost-utility ratio for TARE versus TACE resulted in a 17,397 $US PPP/Quality-adjusted-Life-Years (QALY), and for TARE versus sorafenib ranged from dominant (more effectiveness and lower cost) to 3363 $US PPP/QALY. CONCLUSIONS: Economic evaluations of TARE for HCC treatment are heterogeneous. Overall, TARE is a cost-effective short- and long-term therapy for the treatment of intermediate-advanced HCC.

Cell-free DNA concentration and fragment size fraction correlate with FDG PET/CT-derived parameters in NSCLC patients.

PURPOSE: The aim of our study was to investigate the correlation between cfDNA concentration and fragment size fraction with FDG PET/CT- and CT-derived parameters in untreated NSCLC patient. METHODS: Fifty-three patients diagnosed of locally advanced or metastatic NSCLC who had undergone FDG PET/CT, CT and cfDNA analysis prior to any treatment were included in this retrospective study. CfDNA concentration was measured by fluorometry and fragment size fractions were determined by microchip electrophoresis. [18F]F-FDG PET/CT was performed and standardised uptake values (SUV), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated for primary, extrapulmonary and total disease. CT scans were evaluated according to RECIST 1.1 criteria. RESULTS: CfDNA concentration showed a positive correlation with extrapulmonary MTV (r2 = 0.36, P = 0.009), and extrapulmonary TLG (r2 = 0.35, P = 0.009) and their whole-body (wb) ratios. Higher concentrations of total cfDNA were found in patients with liver lesions. Short fragments of cfDNA (100-250 bp) showed a positive correlation with extrapulmonary MTV (r2 = 0.49, P = 0.0005) and extrapulmonary TLG (r2 = 0.39, P = 0.006) and their respective wb ratios, and a negative correlation with SUVmean (r2 = -0.31, P = 0.03) and SUVmean/SUVmax ratio (r2 = -0.34, P = 0.02). A higher fraction of short cfDNA fragments was found in patients with liver and pleural lesions. CONCLUSIONS: This study supports the hypothesis that cfDNA concentration and short cfDNA fragment size fraction reflect the tumour burden as well as metabolic activity in advanced NSCLC patients. This suggests their suitability as complementary tests for a more accurate diagnosis of tumour metabolic behaviour and to allow personalised therapies.

Diagnostic utility and therapeutic impact of PET/CT [18F]F-Fluoromethylcholine -Choline in the biochemical recurrence of prostate cancer. / Utilidad diagnóstica e impacto terapéutico de la PET/TC con [18F]F-Fluormetilcolina en la recidiva bioquímica del cáncer de próstata.

OBJECTIVE: To assess the diagnostic capability of PET/CT with [18F]F-Fluoromethylcholine in prostate cancer (PC) with biochemical recurrence and its therapeutic impact. MATERIAL AND METHODS: We included 108 patients, diagnosed with PC with biochemical criteria for recurrence. A PET/CT Choline scan was performed by dynamic pelvic and whole body study at 60min post-tracer injection. The relationship between the positive studies and the PSA value was analysed by classifying patients into three groups (<1.2/1.2-2/>2ng/ml), and the diagnostic capacity was assessed with respect to pelvic MRI and the impact on the therapeutic decision. RESULTS: The location of recurrence was identified in 85 of 108 patients (78.7%): 34 local, 47 pelvic lymph nodes and 58 distant lesions, including retroperitoneal, mediastinal lymph nodes and distant organ lesions (bone and lung). Second tumors were diagnosed in 4 patients. No significant differences were found in the percentage of positive studies depending on primary treatment. Patients with PSA>2ng/ml showed a higher percentage of disease detection than patients with a lower PSA level, with significant differences (p<0.0001). PET/CT [18F]F-Choline was able to detect local disease, not previously known from MRI, in 29.41% of patients. PET/CT Choline had an impact on therapeutic management in 67 of 108 patients (62%). CONCLUSIONS: PET/CT with [18F]F-Fluoromethylcholine is a useful tool in the detection of locoregional and disseminated disease of PC treated with suspicion of recurrence, providing a change in therapeutic management in 62% of patients.

Multimodal approach in radioguided surgery in a case of multiple paraganglioma. / Abordaje multimodal en la cirugía radioguiada de un caso de paraganglioma múltiple.

The case involves a 34-year-old woman who underwent surgical removal of a retroperitoneal paraganglioma adjacent to the left kidney's lower pole, previously visualized by CT and MRI. The 123I-MIBG scan was positive for this lesion and, in addition, another uptake was observed located caudally at the level of L5 and of smaller size and less intensity. The second lesion was not considered for surgical removal, due to its lack of morphological definition. One week after surgical intervention, the patient presented difficult-to-control high blood pressure. A second 123I-MIBG scan was performed. The previously described second image was more intense in this study, and surgery was planned to remove it. A combination of techniques including freehand-SPECT and a portable hybrid gamma camera (with optical camera) were used pre-operatively to identify the location of the lesion. The combination of intra-operative laparoscopic gamma probe and portable hybrid gamma camera enabled the tumor to be located, excised, and its complete removal to be monitored. The histopathology analysis confirmed a second paraganglioma.

Additional value of hybrid SPECT/CT systems in neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas.

The aim of this review was to evaluate the potential advantages of SPECT/CT hybrid imaging in the management of neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas. From the collected data, the superiority of fused images was observed as providing both functional/molecular and morphological imaging compared to planar imaging. This provided an improvement in diagnostic imaging, with significant advantages as regards: (1) precise locating of the lesions; (2) an improvement in characterization of the findings, resulting higher specificity, improved sensitivity, and overall greater accuracy, (3) additional anatomical information derived from the CT component; (4) CT-based attenuation correction and potential for volumetric dosimetry calculations, and (5) improvement on the impact on patient management (e.g. in better defining treatment plans, in shortening surgical operating times). It can be concluded that SPECT/CT hybrid imaging provides the nuclear medicine physician with a powerful imaging modality in comparison to planar imaging, providing essential information about the location of lesions, and high quality homogeneous images.

Hybrid-fusion SPECT/CT systems in parathyroid adenoma: Technological improvements and added clinical diagnostic value.

Nuclear medicine traditionally employs planar and single photon emission computed tomography (SPECT) imaging techniques to depict the biodistribution of radiotracers for the diagnostic investigation of a range of disorders of endocrine gland function. The usefulness of combining functional information with anatomy derived from computed tomography (CT), magnetic resonance imaging (MRI), and high resolution ultrasound (US), has long been appreciated, either using visual side-by-side correlation, or software-based co-registration. The emergence of hybrid SPECT/CT camera technology now allows the simultaneous acquisition of combined multi-modality imaging, with seamless fusion of 3D volume datasets. Thus, it is not surprising that there is growing literature describing the many advantages that contemporary SPECT/CT technology brings to radionuclide investigation of endocrine disorders, showing potential advantages for the pre-operative locating of the parathyroid adenoma using a minimally invasive surgical approach, especially in the presence of ectopic glands and in multiglandular disease. In conclusion, hybrid SPECT/CT imaging has become an essential tool to ensure the most accurate diagnostic in the management of patients with hyperparathyroidism.

Dual time-point (18)F-FDG PET/CT to assess response to radiofrequency ablation of lung metastases.

AIM: To establish the usefulness of dual time-point PET/CT imaging in determining the response to radiofrequency ablation (RFA) of solitary lung metastases from gastrointestinal cancer. MATERIALS AND METHODS: This prospective study included 18 cases (3 female, 15 male, mean age 71±15 yrs) with solitary lung metastases from malignant digestive tract tumors candidates for RFA. PET/CT images 1h after injection of 4.07MBq/kg of (18)F-FDG (standard images) were performed at baseline, 1 month, and 3 months after RFA. PET/CT images 2h after injection centered in the thorax at 1 month after RFA were also performed (delayed images). A retention index (RI) of dual time-point images was calculated as follows: RI=(SUVmax delayed image-SUVmax standard image/SUVmax standard image)*100. Pathological confirmation of residual tumor by histology of the treated lesion was considered as local recurrence. A negative imaging follow-up was considered as complete response. RESULTS: Local recurrence was found in 6/18 lesions, and complete response in the remaining 12. The mean percentage change in SUVmax at 1 month and at 3 months showed a sensitivity and specificity for PET/CT of 50% and 33%, and 67% and 92%, respectively. The RI at 1 month after RFA showed a sensitivity and specificity of 83% and 92%, respectively. CONCLUSIONS: Dual time point PET/CT can predict the outcome at one month after RFA in lung metastases from digestive tract cancers. The RI can be used to indicate the need for further procedures to rule out persistent tumor due to incomplete RFA.

Prognostic value of (18)F-FDG PET/CT volumetric parameters in recurrent epithelial ovarian cancer.

OBJECTIVE: Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) from (18)F-FDG PET/CT are emerging prognostic biomarkers in various solid neoplasms. These volumetric parameters and the SUVmax have shown to be useful criteria for disease prognostication in preoperative and post-treatment epithelial ovarian cancer (EOC) patients. The purpose of this study was to evaluate the utility of (18)F-FDG PET/CT measurements to predict survival in patients with recurrent EOC. MATERIAL AND METHODS: Twenty-six patients with EOC who underwent a total of 31 (18)F-FDG PET/CT studies for suspected recurrence were retrospectively included. SUVmax and volumetric parameters whole-body MTV (wbMTV) and whole-body TLG (wbTLG) with a threshold of 40% and 50% of the SUVmax were obtained. Correlation between PET parameters and progression-free survival (PFS) and the survival analysis of prognostic factors were calculated. RESULTS: Serous cancer was the most common histological subtype (76.9%). The median PFS was 12.5 months (range 10.7-20.6 months). Volumetric parameters showed moderate inverse correlation with PFS but there was no significant correlation in the case of SUVmax. The correlation was stronger for first recurrences. By Kaplan-Meier analysis and log-rank test, wbMTV 40%, wbMTV 50% and wbTLG 50% correlated with PFS. However, SUVmax and wbTLG 40% were not statistically significant predictors for PFS. CONCLUSION: Volumetric parameters wbMTV and wbTLG 50% measured by (18)F-FDG PET/CT appear to be useful prognostic predictors of outcome and may provide valuable information to individualize treatment strategies in patients with recurrent EOC.

PET/CT with [18F] fluorodeoxyglucose in the assessment of metabolic response to neoadjuvant chemotherapy in locally advanced breast cancer.

AIM: The aim of this paper was to prospectively evaluate FDG PET/CT in the assessment of metabolic response to neoadjuvant chemotherapy and correlation with tumor cellularity in locally advanced breast cancer. METHODS: Images were acquired with a PET/CT scanner in 50 patients at baseline and after completion of treatment, just before surgery. All findings were confirmed by histopathological analysis. PET/CT quantification (SUVmax) at baseline and after finishing neoadjuvant chemotherapy (4 cycles of epirubicin + cyclophosphamide +/- taxanes) were compared using RECIST criteria and Miller & Payne (M&P) scale. RESULTS: Baseline mean tumor size was 4.4±1.6 cm. Thirty eight patients were considered responders and 12 nonresponders. According to M&P scale, 10 patients had good prognosis (grades 4-5) and 40 patients had bad prognosis (grades 1-3). All patients with grade 5 M&P had no significant postchemotherapy FDG uptake. Patients with bad prognosis had lower SUVmax variation (∆SUVmax) than patients with good prognosis (60.7% vs. 80.5%, P=0.0016). ∆SUVmax was lower in nonresponders than in partial responders according to RECIST criteria (38.9% vs. 67.6%, p<0.001), and was also lower in partial responders than complete responders (67.6% vs. 85.4%, P=0.005). A cut-off ∆SUVmax value of 52% differentiates responders from nonresponders with a sensitivity of 86% and a specificity of 90%. Probability densities of the ∆SUVmax (%) for stable disease (<45), partial (>45 to <82) and complete response (>82) showed an overall accuracy of 78% (Weighted Kappa=0.74). CONCLUSION: PET/CT is useful to monitor response to neoadjuvant chemotherapy in locally advanced breast cancer. ∆SUVmax on PET/CT correlates with tumor cellularity after completion of neoadjuvant chemotherapy.

[Dual-time point images of the liver with (18)F-FDG PET/CT in suspected recurrence from colorectal cancer]. / (18)F-FDG PET/TC con imagen hepática en dos tiempos en la sospecha de recidiva del cáncer colorrectal

AIM: To analyze the potential improvement of (18)F-fluorodeoxyglucose (FDG) PET/CT using additional delayed images of the liver in operated colorectal cancer. MATERIAL AND METHODS: The study prospectively included 71 patients (22 women, 49 men) with mean age of 65 ± 11 years with clinical, analytic or radiological suspicion of current disease. A whole body PET/CT scan was performed at 60 min. (standard images) and after 2 hr (delayed images) post-injection of 4.07 MBq/Kg of (18)F-FDG. Visual and quantitative SUV analysis of PET/CT findings was done. All findings were confirmed by histopathology and/or at least 6 months follow-up. RESULTS: Thirty-seven out of 71 patients were diagnosed of liver metastases (79 metastases). In 38/71 cases there was extra-hepatic disease in the form of local recurrence (10), abdominopelvic (3) or mediastinal (3) lymph nodes, bone (1) or lung metastases (16) and carcinomatosis (10). Sensitivity and specificity in the diagnosis of liver metastases in a patient-by-patient basis in standard (81% and 91%) and in delayed images (95% y 97%) was calculated. The number of lesions detected in delayed images was significantly higher (66/79) than in standard images (57/79). Sensitivity and specificity for PET/CT in the diagnosis of extra-hepatic disease was 84% and 70%, contributing to the detection of synchronous tumors in 5 patients. CONCLUSIONS: PET/CT may be useful in the diagnosis of extra-hepatic disease in suspected recurrence of colorectal cancer. Delayed images on PET/CT may increase the sensitivity to identify liver metastases.

Efficacy of low doses of pamidronate in osteopenic patients administered in the early post-renal transplant.

UNLABELLED: This study evaluates the efficacy of low doses of pamidronate after renal transplantation to prevent bone loss in osteopenic patients. Results show that pamidronate is safe and significantly reduced spinal bone loss when administered immediately after renal transplantation. INTRODUCTION: The purpose of this work is to evaluate the efficacy of two intravenous infusions of pamidronate in the immediate post-transplant period in a renal transplant (RT) population. METHODS: In this 12-month, randomized, double-blind, multicenter trial, 39 kidney recipients with diagnosed osteopenia received two doses of 30 mg of disodium pamidronate (n = 24) or placebo (n = 15), at surgery and 3 months post-RT. All patients received calcium and vitamin D. Bone density of the lumbar spine and total femur was measured by dual-energy X-ray absorptiometry (DXA) and X-rays were performed at RT, 6 and 12 months post-RT. Biochemical and hormonal determinations were performed before and after treatment. RESULTS: Pamidronate significantly reduced spinal bone loss, but no significant benefit was found for the incidence of fractures. Elevated baseline intact parathyroid hormone (iPTH) and bone remodeling markers returned to normal levels 3 months post-RT. However, normal procollagen type I N propeptide (PINP) concentrations were only maintained in the pamidronate group. After RT, a comparable graft function was observed in both groups according to creatinine values, 25-hydroxyvitamin-D (25-OH-D) levels were improved, and serum calcium levels normalized after a transient fall during the first 3 months. CONCLUSION: A low dose of pamidronate prevents bone loss in osteopenic patients when administered immediately after RT.

Value of FDG-PET for monitoring treatment response in patients with advanced GIST refractory to high-dose imatinib. A multicenter GEIS study.

AIM: The aim of this study was to evaluate the utility of positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) in monitoring response in refractory GIST. METHODS: This multicenter study prospectively evaluated 21 patients with locally advanced and/or metastatic GIST refractory to with high-dose imatinib (800 mg/day) treated with doxorubicin 15-20 mg/m2/weekly for 4 cycles, followed by imatinib maintenance (400 mg/day). CT and FDG-PET were performed at baseline and after completion of therapy. RESULTS: Mean baseline tumor size on CT was 5.9 cm. Median progression-free survival (PFS) was 219 days (range 62-1108). Three out of 21 patients (14%) had partial responses (PR) under RECIST criteria, 12 patients (57%) remained stable (SD) and 6 showed progression (PD) of the disease during treatment (29%). Six patients had PR by FDG-PET, 15 showed SD (n=9) or PD (n=6) based on EORTC criteria. Patients with a PFS <6 mo showed a significantly higher ∑SUVmax at baseline (26.04±13.4) than those with PFS≥6 mo (9.82±5.0) (P<0.05). A correlation was found between PET response and PFS: PR 14±6.1 mo, SD 5.5±0.8 mo and PD 3.5±4.1 mo (P<0.05). A residual SUVmax <5 after treatment correlated with improved PFS (314±315 days vs 131±91 days) (P<0.01). Survival curves showed a significant association between PET response and PFS (P<0.05). Patients with wild-type genotype KIT (KIT-WT) showed a significantly lower baseline SUVmax (5.36±1.4) than non-WT KIT (8.40±3.6) (P<0.05). CONCLUSION: FDG-PET is useful in assessing response of GIST refractory to imatinib and correlates with the presence of KIT-WT. Baseline ∑SUVmax can predict response to treatment in this series.

Breast cancer therapy: the role of PET-CT in decision making.

This paper describes the role of positron emission tomography (PET) and PET-computed tomography (CT) in breast cancer patients. Fluorine-18-Fluoro-D-glucose (FDG) has limited diagnostic value in detecting small noninvasive primary tumors, in staging the axillary region in early stages and in the detection of osteoblastic metastases. Better results have been shown in the detection and staging of primary invasive tumors. Significant clinical data are available in the monitoring of primary chemotherapy in locally advanced breast cancer where [(18)F]FDG PET-CT allows prediction of the response even shortly after the onset of therapy. Quantitative evaluation of tumor uptake is necessary. Therapy-induced changes in tumor metabolism may be helpful in making decisions about continuation, modification or cessation of therapy. Therefore, [(18)F]FDG PET-CT appears to be a promising tool for the personalization of breast cancer treatment by its early identification of nonresponders. It offers improved patient care, avoiding ineffective chemotherapy and the side effects while reducing the cost. An area generating high expectations for PET-TC in breast cancer is in monitoring in order to tailor therapy to the tumor characteristics of individual patients who may require tracers other than [(18)F]FDG. The introduction of new PET tracers and the development of new instruments will offer opportunities to improve the role of PET-CT in decision making of therapy in these patients.

[Potential use of bone marrow scintigraphy in suspected prosthetic hip infection evaluated with 99mTc-HMPAO-leukocytes]. / Valor de la gammagrafía de médula macrofágica en el diagnóstico de infección de prótesis total de cadera estudiada con leucocitos Tc-HMPAO.

AIM: To evaluate the usefulness of (99m)Tc-Sulphur colloid when combined with leukocyte scintigraphy in suspected prosthetic hip infection, comparing the results with information from (99m)Tc-HMPAO-leukocyte scintigraphy alone. MATERIALS AND METHODS: Seventy patients (42 women, 28 men; mean age 68 +/- 13 years) with painful hip prostheses and suspicion of infection were evaluated prospectively. All patients had bone scintigraphy, (99m)Tc-HMPAO-labelled white blood cell scintigraphy and (99m)Tc-Sulphur colloid bone marrow scintigraphy. ESR and CRP levels were measured in all patients. The final diagnosis was made with microbiological findings or by clinical follow up of at least 12 months. RESULTS: Infections were diagnosed in 12 of the 70 patients (3 coagulase-negative Staphylococcus, 2 Staphylococcus aureus, 2 Staphylococcus epidermidis, 2 enterococcus and 3 polymicrobial agents). ESR and CRP values were higher in patients with infection than in patients without infection (51.8 +/- 29.4 vs. 25.4 +/- 16.4 and 2.8 +/- 2.2 vs. 1.1 +/- 1.3, respectively; p < 0.05). Bone scintigraphy did not show a characteristic pattern to differentiate infection from aseptic loosening. The pool phase of the bone scintigraphy was positive in only 3/12 patients with infection (25 %). Sensitivity and specificity of the leukocyte scintigraphy was 83 % and 57 %, respectively. When the results of the bone marrow scintigraphy were added, these values increased to 92 % and 98 %, respectively. CONCLUSION: Performing bone marrow scintigraphy significantly improves results when compared with leukocyte scintigraphy alone in the diagnosis of infected hip prostheses. Bone scintigraphy did not help to differentiate aseptic loosening from infection in this series.

Localising imaging in secondary hyperparathyroidism.

Preoperative imaging has proved its use successful in the localization of solitary parathyroid adenomas in patients with suspected primary hyperparathyroidism. However, due to multiglandular disease at presentation patients with renal hyperparathyroidism need to be analyzed separately, making the usefulness of imaging techniques controversial. Recently, improved methods of functional imaging like parathyroid scan with 99mTc-sestamibi or positron emission tomography, especially when combined with computed tomography, can provide additional quantitative and qualitative information that has yet to be assessed. Nuclear medicine procedures could prove useful not only in preoperative diagnosis, but also in the selection of medical or surgical therapeutic alternatives in secondary hyperparathyroidism patients. There is evidence that 99mTc-sestamibi uptake in parathyroid hyperplasia or adenoma is related to biochemical markers of parathyroid function. We are only beginning to identify the factors involved in radiotracer uptake by parathyroid cells and how it can be modulated to obtain more accurate results. This review analyzes the current use of non-invasive imaging modalities in patients with secondary hyperparathyroidism, taking into account the latest trends in the field combining anatomic and functional modalities and the relevant factors linked to radiotracer uptake in abnormal hyperfunctioning parathyroid glands.

Exciton gas compression and metallic condensation in a single semiconductor quantum wire.

We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidence of metallic liquid condensation at low temperatures. First, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Second, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at n{c} approximately 1 x 10;{5} cm;{-1} and T{c} approximately 35 K, respectively.

[Parathyroid carcinoma associated to secondary hyperparathyroidism in hemodialyzed patients. Two cases reports]. / Carcinoma de paratiroides asociado a hiperparatiroidismo secundario en pacientes en hemodiálisis.

Parathyroid carcinoma (PC) is an infrequent disease with a subtle initial presentation and a variable course, necessitating a high index of suspicion to make the correct diagnosis. In chronic failure patients on haemodialysis it becomes even more difficult to suspect this entity since the high prevalence of secondary hyperparathyroidism(SHP). Two patients with PC out of a series of 160 patients with moderate-to-severe SHP submitted for parathyroidectomy are reported. Their clinical features are compared with those of the twenty-two cases previously reported in the literature with a discussion of this pathology. Patients with PC showed higher blood levels of iPTH, total calcium, phosphate and total alkaline phosphatase than the SHP population. The final diagnosis of PC was made after histological study revealing capsular or blood vessel invasion.