Epidemiology of COVID-19 in Northern Ireland, 26 February 2020-26 April 2020.

This paper describes the epidemiology of coronavirus disease 2019 (COVID-19) in Northern Ireland (NI) between 26 February 2020 and 26 April 2020, and analyses enhanced surveillance and contact tracing data collected between 26 February 2020 and 13 March 2020 to estimate secondary attack rates (SAR) and relative risk of infection among different categories of contacts of individuals with laboratory confirmed severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Our results show that during the study period COVID-19 cumulative incidence and mortality was lower in NI than the rest of the UK. Incidence and mortality were also lower than in the Republic of Ireland (ROI), although these observed differences are difficult to interpret given considerable differences in testing and surveillance between the two nations. SAR among household contacts was 15.9% (95% CI 6.6%-30.1%), over 6 times higher than the SAR among 'high-risk' contacts at 2.5% (95% CI 0.9%-5.4%). The results from logistic regression analysis of testing data on contacts of laboratory-confirmed cases show that household contacts had 11.0 times higher odds (aOR: 11.0, 95% CI 1.7-70.03, P-value: 0.011) of testing positive for SARS-CoV-2 compared to other categories of contacts. These results demonstrate the importance of the household as a locus of SARS-CoV-2 transmission, and the urgency of identifying effective interventions to reduce household transmission.

Impact of prediagnostic smoking and smoking cessation on colorectal cancer prognosis: a meta-analysis of individual patient data from cohorts within the CHANCES consortium.

Background: Smoking has been associated with colorectal cancer (CRC) incidence and mortality in previous studies and might also be associated with prognosis after CRC diagnosis. However, current evidence on smoking in association with CRC prognosis is limited. Patients and methods: For this individual patient data meta-analysis, sociodemographic and smoking behavior information of 12 414 incident CRC patients (median age at diagnosis: 64.3 years), recruited within 14 prospective cohort studies among previously cancer-free adults, was collected at baseline and harmonized across studies. Vital status and causes of death were collected for a mean follow-up time of 5.1 years following cancer diagnosis. Associations of smoking behavior with overall and CRC-specific survival were evaluated using Cox regression and standard meta-analysis methodology. Results: A total of 5229 participants died, 3194 from CRC. Cox regression revealed significant associations between former [hazard ratio (HR) = 1.12; 95 % confidence interval (CI) = 1.04-1.20] and current smoking (HR = 1.29; 95% CI = 1.04-1.60) and poorer overall survival compared with never smoking. Compared with current smoking, smoking cessation was associated with improved overall (HR<10 years = 0.78; 95% CI = 0.69-0.88; HR≥10 years = 0.78; 95% CI = 0.63-0.97) and CRC-specific survival (HR≥10 years = 0.76; 95% CI = 0.67-0.85). Conclusion: In this large meta-analysis including primary data of incident CRC patients from 14 prospective cohort studies on the association between smoking and CRC prognosis, former and current smoking were associated with poorer CRC prognosis compared with never smoking. Smoking cessation was associated with improved survival when compared with current smokers. Future studies should further quantify the benefits of nonsmoking, both for cancer prevention and for improving survival among CRC patients, in particular also in terms of treatment response.

18F-FDG PET-CT uptake is a feature of both normal diameter and aneurysmal aortic wall and is not related to aneurysm size.

PURPOSE: Aortic metabolic activity is suggested to correlate with presence and progression of aneurysmal disease, but has been inadequately studied. This study investigates the 2-[(18)F] fluoro-2-deoxy-D-glucose ((18)F-FDG) uptake in a population of infra-renal abdominal aortic aneurysms (AAA), compared to a matched non-aneurysmal control group. METHODS: The Positron Emission Tomography - Computed Tomography (PET/CT) database was searched for infra-renal AAA. Exclusion criteria were prior repair, vasculitis, and saccular/mycotic thoracic or thoraco-abdominal aneurysms. Matching of 159 non-aneurysmal (<3 cm diameter) controls from the same population was assessed. Infra-renal aortic wall FDG uptake was assessed using visual analysis; maximum standardized uptake value (SUVmax) and target to background mediastinal blood pool ratio (TBR) were documented. Predictors of FDG uptake (age, sex, aortic diameter, hypertension, statin use, and diabetes) were assessed using univariate analysis. Follow-up questionnaires were sent to referring clinicians. RESULTS: Aneurysms (n = 151) and controls (n = 159) were matched (p > 0.05) for age, sex, diabetes, hypertension, smoking status, statin use, and indication for PET/CT. Median aneurysm diameter was 5.0 cm (range 3.2-10.4). On visual analysis there was no significant difference in the overall numbers with increased visual uptake 24% (36/151) in the aneurysm group vs. 19% (30/159) in the controls, p = ns. SUVmax was slightly lower in the aneurysm group vs. controls (mean (2 SD) 1.75(0.79) vs. 1.84(0.58), p = 0.02). However there was no difference in TBR between the AAA group and controls (mean (2 SD) 1.03 (0.46) vs. 1.05(0.31), p = 0.36). During a median 18 (interquartile range 8-35) months' follow-up 20 were repaired and four were confirmed ruptured. CONCLUSIONS: The level of metabolic activity as assessed by (18)F-FDG PET/CT in infra-renal AAA does not correlate with aortic size and does not differ between aneurysms and matched controls.

Establishment of a UK-wide network to facilitate the acquisition of quality assured FDG-PET data for clinical trials in lymphoma.

BACKGROUND: Multicentre trials are required to determine how [fluorine-18]-2-fluoro-2-deoxy-D-glucose-positron emission tomography imaging can guide cancer treatment. Consistency in quality control (QC), scan acquisition and reporting is mandatory for high-quality results, which are comparable across sites. METHODS: A national positron emission tomography (PET) clinical trials network (CTN) has been set up with a 'core laboratory' to coordinate QC and interpret scans. The CTN is involved in trials in Hodgkin's lymphoma [Randomised Phase III trial to determine the role of FDG-PET Imaging in Clinical Stages IA/IIA Hodgkin's Disease (RAPID) and Randomised Phase III trial to assess response adapted therapy using FDG-PET imaging in patients with newly diagnosed, advanced Hodgkin lymphoma (RATHL)] and diffuse large B-cell lymphoma [Blinded evaluation of prognostic value of FDG-PET after 2 cycles of chemotherapy in diffuse large B-cell Non-Hodgkins Lymphoma, a sub-study of the R-CHOP-21 vs R-CHOP-14 trial (R-CHOP PET substudy)]. Approval to join requires scanner validation and agreement to follow a standard QC protocol. Scans are transferred to the core laboratory and reported centrally according to predetermined criteria. RESULTS: The qualification procedure was carried out on 15 scanners. All scanners were able to demonstrate the necessary quantitative accuracy, and following modification of image reconstruction where necessary, scanners demonstrated comparable recovery coefficients (RCs) indicating similar performance. The average RC (±1 standard deviation) was 0.56 ± 0.095 for the 13-mm sphere. Reports from 444 of 473 (94%) patients in RAPID and 67 of 73 (92%) patients in RATHL were available for randomisation of therapy. CONCLUSIONS: The CTN has enabled consistent quality assured PET results to be obtained from multiple centres in time for clinical decision making. The results of trials will be significantly strengthened by this system.

Regression of melanoma metastases following treatment with the n-bisphosphonate zoledronate and localised radiotherapy.

We report a case of regression of pulmonary and bony metastases in a patient with malignant melanoma following palliative treatment with systemic zoledronate and localised radiotherapy to the bone. Zoledronate is a potent new bisphosphonate used for the treatment of metabolic bone diseases including bone metastases due to its inhibitory effect on osteoclasts. In the context of metastatic cancer zoledronate is routinely used to improve bone pain and reduce the frequency of skeletal events. There is also an increasing body of evidence suggesting that bisphosphonates exhibit anti-tumour properties. Bisphosphonates are able to activate Vgamma9Vdelta2 gamma-delta T cells which can be key players in the immune defence against malignant cells. Furthermore bisphosphonates have direct anti-proliferative, anti-metastatic and pro-apoptotic effects on tumour cells. These actions, together with their low side effect profile, may prove to be useful therapeutic tools in the treatment of cancer even in the absence of bone metastases. On the basis of this case report we here review the current literature on present preclinical and clinical studies using bisphosphonates for the treatment of cancer.

Diabetes and bone: advantages and limitations of radiological, radionuclide and hybrid techniques in the assessment of diabetic foot.

A common cause of morbidity and mortality in diabetic patients are foot infection/complications often leading to amputation of lower extremities. Various radiological and radionuclide techniques are available for the assessment of diabetic patients with bone or soft tissue infections. However, there are several advantages and limitations. The major limitation of all these techniques is their inability to accurately differentiate osteomyelitis from charcot's/neuropathic joints. Radiologically, magnetic resonance imaging (MRI) is the technique of choice and a radiolobeled white cell scan is a useful nuclear medicine technique in the evaluation of diabetic patients with suspected foot infection. In this review we discuss the efficacy of radiological and radionuclide techniques in the assessment of diabetic foot infection.

[18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a diagnostic tool for neurofibromatosis 1 (NF1) associated malignant peripheral nerve sheath tumours (MPNSTs): a long-term clinical study.

BACKGROUND: Malignant peripheral nerve sheath tumours (MPNSTs) are difficult to detect in neurofibromatosis 1 (NF1) individuals. The purpose was to evaluate [(18)F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) and PET computed tomography (CT) as a diagnostic tool for MPNST in NF1 patients with symptomatic plexiform neurofibromas and to verify the diagnosis by pathology and clinical follow-up. PATIENTS AND METHODS: NF1 individuals with symptomatic plexiform neurofibromas underwent clinical evaluation and magnetic resonance imaging. Qualitative FDG PET and PET CT associated with semi-quantitative maximum standard uptake value (SUVmax) assessed possible malignant change. Excision/biopsy verified the diagnosis when possible and clinical follow-up was undertaken in all patients. RESULTS: In all, 116 lesions were detected in 105 patients aged 5-71 years, including 80 plexiform neurofibromas, five atypical neurofibromas, 29 MPNST and two other cancers. Biopsy confirmed the findings in 59 tumours and no MPNST was diagnosed on clinical follow-up of 23 lesions diagnosed as benign on FDG PET and PET CT. FDG PET and PET CT diagnosed NF1-associated tumours with a sensitivity of 0.89 [95% confidence interval (CI) 0.76-0.96] and a specificity of 0.95 (CI 0.88-0.98), but the SUVmax level did not predict tumour grade. CONCLUSION: FDG PET and PET CT is a sensitive and specific diagnostic tool for NF1-associated MPNST. Other PET tracers will be required to solve the problem of predicting tumour grade.

Measurement of the internal dose to families of outpatients treated with 131I for hyperthyroidism.

OBJECTIVE: The aim of this study was to measure the internal dose received by family members from ingestion of radioactive contamination after outpatient therapy. MATERIALS AND METHODS: Advice was given to minimise transfer of radioiodine. Home visits were made approximately 2, 7 and 21 days after treatment to measure radioactivity in the thyroids of family members. A decay correction was applied to radioactivity detected assuming ingestion had occurred at the earlier contact time, either the day of treatment or the previous home visit. An effective half-life of 6 or 7 days was used depending on age. Thyroid activity was summed if activity was found at more than one visit in excess of the amount attributable to radioactive decay. Effective dose (ED) was calculated using ICRP72. RESULTS AND DISCUSSION: Fifty-three adults and 92 children, median age 12 (range 4-17) years participated. Median administered activity was 576 (range 329-690) MBq (131)I. Thyroid activity ranged from 0 to 5.4 kBq in the adults with activity detected in 17. Maximum adult ED was 0.4 mSv. Thyroid activity ranged from 0 to 11.8 kBq in the children with activity detected in 26. The two highest values of 5.0 and 11.8 kBq occurred in children aged 5 and 14 years from different families. Eighty-five children had no activity or <1 kBq detected. ED was <0.2 mSv in 86 out of 92 children (93%). Previous published data showed 93% of children received an ED

Imaging neuroendocrine tumours with radionuclide techniques.

Neuroendocrine tumours (NETs) are a rare type of tumour that can range from well differentiated slow growing tumours to poorly differentiated aggressive tumours. NETs can arise in different parts of the body. Patients often present with a large spectrum of clinical syndromes, which depend on the presence of hormones secreted by the tumour type or by a mass effect. Several imaging modalities are used in the diagnosis of NETs. Radionuclide imaging plays an important role in diagnosis, staging and treatment of these tumours. Several radiopharmaceuticals are used to image NETs and are based on different cellular uptake mechanisms. This review will focus on the functional imaging of NETs using single photon emission computed tomography and positron emission tomography radiopharmaceuticals.

Social capital, deprivation and self-rated health: Does reporting heterogeneity play a role? Results from the English Longitudinal Study of Ageing.

Self-rated health (SRH) is commonly assessed in large surveys, though responses can be influenced by different individuals' perceptions of and beliefs about health. Therefore, instead of providing evidence of 'true' health disparities across groups, findings may actually reflect reporting heterogeneity. Using data from participants aged 50 years and older from the English Longitudinal Study of Ageing (ELSA) Wave 3 (2006/07; participation rate = 73%), associations between three dimensions of social capital (local area & trust, social support and social networks), deprivation and SRH were examined using the vignette methodology in 2341 individuals who completed both the self-report and at least one of the 18 vignettes. Analysis employed a hierarchical probit model (HOPIT). Individuals expressing low local area & trust social capital (beta = -0.276, p < 0.001) and those with poor social networks (beta = -0.280, p < 0.001) were more likely to report poor SRH in HOPIT models accounting for reporting heterogeneity, but unadjusted ordered probit analyses still correctly show a negative relationship between low local area & trust social capital (beta = -0.243, p < 0.001) and those with poor social networks (beta = -0.210, p < 0.01), though they somewhat tend to underestimate its strength. Neither social support nor deprivation appeared to have any effect on SRH regardless of reporting heterogeneity. Anchoring vignettes offer a relatively uncomplicated and cost-effective way of identifying and correcting for reporting heterogeneity to improve comparative validity of self-report measures of health. This analysis underlines the need for caution when using unadjusted self-reported measures to study the effects of social capital on health.

Fruit and vegetable intake and risk of incident of type 2 diabetes: results from the consortium on health and ageing network of cohorts in Europe and the United States (CHANCES).

BACKGROUND/OBJECTIVES: There is limited information to support definitive recommendations concerning the role of diet in the development of type 2 Diabetes mellitus (T2DM). The results of the latest meta-analyses suggest that an increased consumption of green leafy vegetables may reduce the incidence of diabetes, with either no association or weak associations demonstrated for total fruit and vegetable intake. Few studies have, however, focused on older subjects. SUBJECTS/METHODS: The relationship between T2DM and fruit and vegetable intake was investigated using data from the NIH-AARP study and the EPIC Elderly study. All participants below the age of 50 and/or with a history of cancer, diabetes or coronary heart disease were excluded from the analysis. Multivariate logistic regression analysis was used to calculate the odds ratio of T2DM comparing the highest with the lowest estimated portions of fruit, vegetable, green leafy vegetables and cabbage intake. RESULTS: Comparing people with the highest and lowest estimated portions of fruit, vegetable or green leafy vegetable intake indicated no association with the risk of T2DM. However, although the pooled OR across all studies showed no effect overall, there was significant heterogeneity across cohorts and independent results from the NIH-AARP study showed that fruit and green leafy vegetable intake was associated with a reduced risk of T2DM OR 0.95 (95% CI 0.91,0.99) and OR 0.87 (95% CI 0.87,0.90) respectively. CONCLUSIONS: Fruit and vegetable intake was not shown to be related to incident T2DM in older subjects. Summary analysis also found no associations between green leafy vegetable and cabbage intake and the onset of T2DM. Future dietary pattern studies may shed light on the origin of the heterogeneity across populations.

Alcoholic beverage preference and diabetes incidence across Europe: the Consortium on Health and Ageing Network of Cohorts in Europe and the United States (CHANCES) project.

BACKGROUND/OBJECTIVES: It is unknown if wine, beer and spirit intake lead to a similar association with diabetes. We studied the association between alcoholic beverage preference and type 2 diabetes incidence in persons who reported to consume alcohol. SUBJECTS/METHODS: Ten European cohort studies from the Consortium on Health and Ageing: Network of Cohorts in Europe and the United States were included, comprising participant data of 62 458 adults who reported alcohol consumption at baseline. Diabetes incidence was based on documented and/or self-reported diagnosis during follow-up. Preference was defined when ⩾70% of total alcohol consumed was either beer, wine or spirits. Adjusted hazard ratios (HRs) were computed using Cox proportional hazard regression. Single-cohort HRs were pooled by random-effects meta-analysis. RESULTS: Beer, wine or spirit preference was not related to diabetes risk compared with having no preference. The pooled HRs were HR 1.06 (95% confidence interval (CI) 0.93, 1.20) for beer, HR 0.99 (95% CI 0.88, 1.11) for wine, and HR 1.19 (95% CI 0.97, 1.46) for spirit preference. Absolute wine intake, adjusted for total alcohol, was associated with a lower diabetes risk: pooled HR per 6 g/day was 0.96 (95% CI 0.93, 0.99). A spirit preference was related to a higher diabetes risk in those with a higher body mass index, in men and women separately, but not after excluding persons with prevalent diseases. CONCLUSIONS: This large individual-level meta-analysis among persons who reported alcohol consumption revealed that the preference for beer, wine, and spirits was similarly associated with diabetes incidence compared with having no preference.

Five year follow up of laser in situ keratomileusis for all levels of myopia.

AIMS: To assess the long term refractive and visual outcome of patients who have laser in situ keratomileusis (LASIK) surgery. METHODS: This was a retrospective study of visual and refractive outcome of patients who had LASIK surgery performed in 1998 and 1999. All levels of myopia were included in the study. 49 patients attended for follow up. The main outcome measures were safety, predictability, efficacy, and stability. Postoperative complications and aberrations were also recorded. The mean preoperative spherical equivalent was -4.85. RESULTS: At 2 months postoperatively 67% of eyes were within plus or minus 0.5D of attempted correction with 81% within plus or minus 1.0D. At 5 years postoperatively 60% of eyes were within plus or minus 0.5D of attempted correction with 83% within plus or minus 1.0D. 88% of eyes had a vision of 6/12 or better at 2 months compared to 89% of eyes at 5 years. Best spectacle corrected visual acuity (BSCVA) was unchanged or improved in 51%. No eye lost more than one line of BSCVA. Overall, there was regression towards myopia with a mean change in refraction of -0.5D over the 5 years. As expected, severely myopic patients regressed more with a mean change of -1.06D. However, there was a high level of patient satisfaction with the surgery. CONCLUSION: LASIK surgery offers predictable results in terms of refractive and visual outcome with mild regression in refraction over time.

The role of sentinel lymph node biopsy in patients with differentiated thyroid carcinoma.

AIM: To evaluate the "state of art" of clinical role of sentinel lymph node (SLN) biopsy procedure in patients affected by differentiated thyroid carcinoma. METHODS: All papers cited on PubMed/MEDLINE until June 2005, published in English, and referred to the key words "sentinel lymph node biopsy" AND "thyroid carcinoma" OR "thyroid cancer" were reviewed for the purpose of the present study. RESULTS: The first method used for SLN biopsy in thyroid carcinoma patients was the vital blue dye technique. This technique had some disadvantages as: (a) risk of disruption of the lymphatic channels deriving from the thyroid cancer; (b) difficulty in disclosing SLN lying outside the central compartment; (c) parathyroid glands can take up blue dye and, thus, can be misinterpreted as lymph nodes. Some of the above cited disadvantages were overcome by using the lymphoscintigraphy and intraoperative gamma probe technique. A combination of the blue dye and gamma probe technique has also been proposed with synergic results. CONCLUSION: The reported advantages of the SLN biopsy in small differentiated thyroid carcinoma patients can be resumed as follows: (a) better selection of patients who would benefit from compartment oriented nodal dissection; (b) more accurate lymph node staging; (c) better selection of patients who can require (131)I treatment after surgery (SLN positive for metastasis); (d) better identification of SLN located out of the central compartment.

Sir William Wilde: an enlightened editor.

This paper examines Sir William Wilde's peculiar genius as editor, his contribution to the Irish Journal of Medical Science in ensuring its endurance and making it a treasure-house of the history of medicine in Ireland.

Comparison of positron emission tomography scanning and sentinel node biopsy in the detection of micrometastases of primary cutaneous malignant melanoma.

PURPOSE: Sentinel node biopsy (SNB) is a surgical technique for detecting micrometastatic disease in the regional draining nodes. 2-fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) scanning is an imaging technique that can detect clinically undetectable metastases. This prospective study was undertaken to compare the sensitivity of FDG-PET scanning with SNB in the detection of micromatastatic malignant melanoma. PATIENTS AND METHODS: Fifty consecutive patients (23 women, 27 men; mean age, 53 years) with primary melanoma >1 mm thick or lymphatic invasion were recruited (mean, 2.41 mm). Primary lesions had been narrowly excised (<1 cm). Patients underwent PET scanning followed by SNB, using a dual technique. Preoperative lymphoscintigraphy was used to identify the draining basin. Lymph nodes were examined histologically and immunostained for S100 and HMB 45. RESULTS: The sentinel node (SN) was identified in all patients. Fourteen patients (28%) had positive SNBs, including eight patients with melanoma <1.5 mm thick. In none of these 14 patients did PET scans identify metastatic disease in the SN or draining basin. In seven patients, the PET scans were positive in other locations, and in four cases, this was suspicious of metastatic disease. However, no patient has developed recurrent melanoma (mean follow-up, 15 months). All patients with positive SNBs underwent therapeutic lymph node dissection. Further lymph node involvement was found in two patients (primary lesions, 1.3 mm and 3.5 mm thick). CONCLUSION: This study demonstrates the limitations of FDG-PET scanning in staging patients with primary melanoma. SNB is the only reliable method for identifying micrometastatic disease in the regional draining node.

A retrospective review of visual outcome and complications in the treatment of retinoblastoma.

The aim of this study was to look at the visual outcome and treatment complications of children diagnosed with Retinoblastoma during the years 1985-2003 inclusive. A retrospective review of all patients records was performed. Patient characteristics, treatment methods and complications were recorded. Twenty eight children presented to Temple street Hospital between 1985-2003. Six of these infants had bilateral tumours. The mean age at presentation was 23.7 months. Sixty-nine percent presented with Leucocoria, of these 33% also had a squint. The mean duration of symptoms was only known in 58% and this figure was approximately 19.8 months. Enucleation was performed in 24 eyes of 24 patients. Three patients required adjuvant chemotherapy post enucleation. Two eyes was treated with external beam radiation and one eye with plaque radiotherapy. One eye (second eye) was treated with systemic chemotherapy and radiation. Five eyes of three patients were treated with systemic chemotherapy followed by adjuvant Argon laser, cryotherapy and diode laser to each eye.The complications of each treatment group was recorded. The visual outcome in the salvaged eyes was favourable. There were no deaths recorded. Though chemotherapy with adjuvant local treatments provide adequate treatment for early tumours, enucleation still plays a major role in the treatment of Retinoblastoma. The total eye salvage rate in this study was 29% with an enucleation rate of 90% in unilateral cases and 33% in bilateral cases. Sixty-six percent of bilateral eyes affected were salvaged. Seventy-one percent of tumours were diagnosed after a parent noticed a gross abnormality of the eye. This highlights the possible need for screening for retinoblastoma in the infant population.

Parathyroid imaging with technetium-99m-sestamibi: preoperative localization and tissue uptake studies.

The accepted radionuclide method for imaging abnormal parathyroid tissue has been the combined use of [99mTc]pertechnetate 201Tl-chloride. Various problems with this approach, however, have suggested the need for an improved parathyroid imaging agent. This study examined the use of 99mTc-sestamibi as a parathyroid imaging agent compared with 201Tl-chloride. Fifty-seven patients were scanned with both 99mTc-sestamibi and 201Tl preoperatively. There were 40 adenomas, of which 37 were localized with 201Tl and 39 with sestamibi. Fifteen patients had hyperplastic glands, of which 29 glands were localized with 201Tl and 32 with sestamibi. Possible differences in uptake of the two agents by thyroid and parathyroid tissue were examined by administering 10 MBq of each agent to patients undergoing surgical exploration and biopsy. Preoperatively 20 patients were studied (13 adenomas and 7 with hyperplasia). Thallium-201 uptake was higher in both the parathyroid and thyroid tissue than sestamibi. However, the uptake per gram of parathyroid tissue of sestamibi was higher than the uptake per gram of thyroid tissue. This was not true for 201Tl. Technetium-99m-sestamibi was at least as effective as 201Tl in parathyroid localization. This may be partly due to a higher target-to-background ratio, but also to the superior physical characteristics of 99mTc.

Comparison of technetium-99m-HM-PAO leukocytes with indium-111-oxine leukocytes for localizing intraabdominal sepsis.

Technetium-99m-HM-PAO [( 99mTc]HM-PAO) leukocyte and indium-111-oxine (111In-oxine) leukocyte scanning were carried out simultaneously in 41 patients at 4 hr and 24 hr after reinjection to determine whether the 4-hr 99mTc scan could replace the 24-hr 111In scan for detecting intraabdominal sepsis. Abdominal infection was confirmed in 12 cases. The 4-hr 99Tc-leukocyte scan, the 4-hr 111In-leukocyte scan, and the 24-hr 111In-leukocyte scan yielded a sensitivity of 100%, 67%, and 100%, respectively, and a specificity of 62%, 90%, and 86%, respectively. The 24-hr 99mTc-leukocyte scan also produced a sensitivity of 100%, but it was falsely positive in all 29 cases without infection due to physiologic bowel uptake. False-positive 4-hr 99mTc-leukocyte scans were also produced by physiologic bowel uptake in seven cases all of whom had true-negative 4-hr and 24-hr 111In-leukocyte scans. Because of the high incidence of false-positive 4-hr [99mTc]HM-PAO leukocyte scans, it was concluded that they could not replace 24-hr 111In-leukocyte scans for detecting intraabdominal sepsis, and that serial 99mTc leukocyte scans starting earlier than 4 hr after reinjection must be evaluated.