Baseline PET radiomics outperforms the IPI risk score for prediction of outcome in diffuse large B-cell lymphoma.

The objective of this study is to externally validate the clinical positron emission tomography (PET) model developed in the HOVON-84 trial and to compare the model performance of our clinical PET model using the international prognostic index (IPI). In total, 1195 patients with diffuse large B-cell lymphoma (DLBCL) were included in the study. Data of 887 patients from 6 studies were used as external validation data sets. The primary outcomes were 2-year progression-free survival (PFS) and 2-year time to progression (TTP). The metabolic tumor volume (MTV), maximum distance between the largest lesion and another lesion (Dmaxbulk), and peak standardized uptake value (SUVpeak) were extracted. The predictive values of the IPI and clinical PET model (MTV, Dmaxbulk, SUVpeak, performance status, and age) were tested. Model performance was assessed using the area under the curve (AUC), and diagnostic performance, using the positive predictive value (PPV). The IPI yielded an AUC of 0.62. The clinical PET model yielded a significantly higher AUC of 0.71 (P < .001). Patients with high-risk IPI had a 2-year PFS of 61.4% vs 51.9% for those with high-risk clinical PET, with an increase in PPV from 35.5% to 49.1%, respectively. A total of 66.4% of patients with high-risk IPI were free from progression or relapse vs 55.5% of patients with high-risk clinical PET scores, with an increased PPV from 33.7% to 44.6%, respectively. The clinical PET model remained predictive of outcome in 6 independent first-line DLBCL studies, and had higher model performance than the currently used IPI in all studies.

The Impact of Interactive MRI-Based Radiologist Review on Radiotherapy Target Volume Delineation in Head and Neck Cancer.

BACKGROUND AND PURPOSE: Peer review of head and neck cancer radiation therapy target volumes by radiologists was introduced in our center to optimize target volume delineation. Our aim was to assess the impact of MR imaging-based radiologist peer review of head and neck radiation therapy gross tumor and nodal volumes, through qualitative and quantitative analysis. MATERIALS AND METHODS: Cases undergoing radical radiation therapy with a coregistered MR imaging, between April 2019 and March 2020, were reviewed. The frequency and nature of volume changes were documented, with major changes classified as per the guidance of The Royal College of Radiologists. Volumetric alignment was assessed using the Dice similarity coefficient, Jaccard index, and Hausdorff distance. RESULTS: Fifty cases were reviewed between April 2019 and March 2020. The median age was 59 years (range, 29-83 years), and 72% were men. Seventy-six percent of gross tumor volumes and 41.5% of gross nodal volumes were altered, with 54.8% of gross tumor volume and 66.6% of gross nodal volume alterations classified as "major." Undercontouring of soft-tissue involvement and unidentified lymph nodes were predominant reasons for change. Radiologist review significantly altered the size of both the gross tumor volume (P = .034) and clinical target tumor volume (P = .003), but not gross nodal volume or clinical target nodal volume. The median conformity and surface distance metrics were the following: gross tumor volume Dice similarity coefficient = 0.93 (range, 0.82-0.96), Jaccard index = 0.87 (range, 0.7-0.94), Hausdorff distance = 7.45 mm (range, 5.6-11.7 mm); and gross nodular tumor volume Dice similarity coefficient = 0.95 (0.91-0.97), Jaccard index = 0.91 (0.83-0.95), and Hausdorff distance = 20.7 mm (range, 12.6-41.6). Conformity improved on gross tumor volume-to-clinical target tumor volume expansion (Dice similarity coefficient = 0.93 versus 0.95, P = .003). CONCLUSIONS: MR imaging-based radiologist review resulted in major changes to most radiotherapy target volumes and significant changes in volume size of both gross tumor volume and clinical target tumor volume, suggesting that this is a fundamental step in the radiotherapy workflow of patients with head and neck cancer.

The frequency of change in five-point scale score with a Bayesian penalised likelihood PET reconstruction algorithm on interim FDG PET-CT and its potential implications for therapy decisions in Hodgkin's lymphoma.

AIM: To assess the effect of a Bayesian penalised likelihood (BPL) reconstruction algorithm on the five-point scale (5-PS) score, response categorisation, and potential implications for therapy decisions after interim 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)-computed tomography (CT) (iPET-CT) to guide treatment in classical Hodgkin's lymphoma (HL). MATERIALS AND METHODS: The present study included new patients with HL undergoing iPET-CT from 2014-2019 after two cycles of doxorubicin (Adriamycin), bleomycin, vincristine, and dacarbazine (ABVD). Two reporters categorised response using the 5-PS and measured maximum standardised uptake values (SUVmax) of the most avid tumour residuum, mediastinal blood pool, and normal liver with ordered subset expected maximisation (OSEM) and BPL reconstructions. RESULTS: Eighty-one iPET-CT examinations were reviewed. Compared with OSEM, BPL increased the 5-PS score by a single score in 18/81 (22.2%) patients. The frequency of potential treatment intensification by changing a score of 3-4 was 13.6% (11/81) and represented 25% (11/44) of patients with a score of 3 on OSEM. All 11 patients remained in remission without a change in therapy (mean 63 months) except one who required second-line treatment for refractory disease. Median SUVmax of tumour residuum was significantly higher with BPL compared with OSEM (2.7 versus 2.4, p<<0.0001), whilst liver SUVmax was significantly lower for both reporters (up to 6.6%, p<0.0001). CONCLUSION: BPL PET reconstruction increased the 5-PS score on iPET-CT in 22% of HL patients and can potentially result in unnecessary treatment escalation in over half of these patients.

Cost-Effectiveness of Shortening Treatment Duration Based on Interim PET Outcome in Patients With Diffuse Large B-cell Lymphoma.

BACKGROUND: Guideline recommendations for diffuse large-B-cell lymphoma (DLBCL) treatment are shifting from long to short treatment duration, although it is still unclear whether shortening treatment duration does not cause any harm. As interim PET (I-PET) has high negative predictive value for progression, we evaluated the cost-effectiveness of shortening treatment duration dependent on I-PET result. MATERIALS AND METHODS: We developed a Markov cohort model using the PET Re-Analysis (PETRA) database to evaluate a long treatment duration (LTD) strategy, ie 8x R-CHOP or 6x R-CHOP plus 2 R, and a short treatment duration (STD) strategy, ie 6x R-CHOP. Strategies were evaluated separately in I-PET2 positive and I-PET2 negative patients. Outcomes included total costs and quality-adjusted life-years (QALYs) per patient (pp) from a societal perspective. Net monetary benefit (NMB) per strategy was calculated using a willingness-to-pay threshold of €50,000/QALY. Robustness of model predictions was assessed in sensitivity analyses. RESULTS: In I-PET2 positive patients, shortening treatment duration led to 50.4 additional deaths per 1000 patients. The STD strategy was less effective (-0.161 [95%CI: -0.343;0.028] QALYs pp) and less costly (-€2768 [95%CI: -€8420;€1105] pp). Shortening treatment duration was not cost-effective (incremental NMB -€5281). In I-PET2 negative patients, shortening treatment duration led to 5.0 additional deaths per 1000 patients and a minor difference in effectiveness (-0.007 [95%CI: -0.136;0.140] QALY pp). The STD strategy was less costly (-€5807 [95%CI: -€10,724;-€2685] pp) and led to an incremental NMB of €5449, indicating that it is cost-effective to shorten treatment duration. Robustness of these findings was underpinned by deterministic and probabilistic sensitivity analyses. CONCLUSION: Treatment duration should not be shortened in I-PET2 positive patients whereas it is cost-effective to shorten treatment duration in I-PET2 negative patients.

Optimal timing and criteria of interim PET in DLBCL: a comparative study of 1692 patients.

Interim 18F-fluorodeoxyglucose positron emission tomography (Interim-18F-FDG-PET, hereafter I-PET) has the potential to guide treatment of patients with diffuse large B-cell lymphoma (DLBCL) if the prognostic value is known. The aim of this study was to determine the optimal timing and response criteria for evaluating prognosis with I-PET in DLBCL. Individual patient data from 1692 patients with de novo DLBCL were combined and scans were harmonized. I-PET was performed at various time points during treatment with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy. Scans were interpreted using the Deauville score (DS) and change in maximum standardized uptake value (ΔSUVmax). Multilevel Cox proportional hazards models corrected for International Prognostic Index (IPI) score were used to study the effects of timing and response criteria on 2-year progression-free survival (PFS). I-PET after 2 cycles (I-PET2) and I-PET4 significantly discriminated good responders from poor responders, with the highest hazard ratios (HRs) for I-PET4. Multivariable HRs for a PET-positive result at I-PET2 and I-PET4 were 1.71 and 2.95 using DS4-5, 4.91 and 6.20 using DS5, and 2.93 and 4.65 using ΔSUVmax, respectively. ΔSUVmax identified a larger proportion of poor responders than DS5 did. For all criteria, the negative predictive value was >80%, and positive predictive values ranged from 30% to 70% at I-PET2 and I-PET4. Unlike I-PET1, I-PET3 discriminated good responders from poor responders using DS4-5 and DS5 thresholds (HRs, 2.94 and 4.67, respectively). I-PET2 and I-PET4 predict good response equally during R-CHOP therapy in DLBCL. Optimal timing and response criteria depend on the clinical context. Good response at I-PET2 is suggested for de-escalation trials, and poor response using ΔSUVmax at I-PET4 is suggested for randomized trials that are evaluating new therapies.

18F-FDG-PET in guided dose-painting with intensity modulated radiotherapy in oropharyngeal tumours: A phase I study (FiGaRO).

BACKGROUND AND PURPOSE: The FiGaRO trial assessed the feasibility and safety of using an FDG-PET-based dose-painting technique to deliver a radiotherapy (RT) boostto the FDG-avid primary tumour in patients with locally advanced high and intermediate risk oropharyngeal cancer. MATERIALS AND METHOD: Patients underwent a planning 18FDG-PET-CT scan, immobilised in the treatment position, after one cycle of induction chemotherapy. The volume of persistent FDG-avidity in the primary tumour was escalated to 71.5 Gy in30 fractions delivered using a simultaneous integrated boost Intensity Modulated RT (SIB-IMRT) technique. RT was delivered with concomitant Cisplatin following 2 cycles of induction chemotherapy. The primary outcome was the incidence of grade ≥ 3 late mucosal toxicity 12 months post-treatment, with an excess rate of >10% regarded as unacceptable. RESULTS: Twenty-nine patients were included and twenty-four were treated between 2014 and 2018, in two UK centres. Median follow-up was 36 months (range 4-56 months). Pre-defined planning target volume objectives and organ at risk dose constraints were met in all cases. There were no incidents of acute grade 4 toxicity. There were 4 cases of grade ≥ 3 mucosal toxicity at 12 months post-treatment (19.1%). There were no cases of persistent mucosal ulceration at 12 months. Overall survival at 3-years was 87.5%, 92.9% for intermediate and 70.0% for high risk patients. CONCLUSION: Late toxicity rates, although higher than anticipated, are comparable to contemporary published data for standard dose chemo-IMRT. Results suggest improved 3y survival rates for high risk patients. This approach merits further investigation. ClinicalTrials.gov Identifier: NCT02953197.

PET-CT in the UK: current status and future directions.

Combined positron-emission tomography and computed tomography (PET-CT) has taken the oncological world by storm since being introduced into the clinical domain in the early 21(st) century and is firmly established in the management pathway of many different tumour types. Non-oncological applications of PET-CT represent a smaller but steadily growing area of interest. PET-CT continues to be the focus of a large number of research studies and keeping up-to-date with the literature is important but represents a challenge. Consequently guidelines recommending PET-CT usage need to be revised regularly to encompass new developments. The purpose of this article is twofold: first, it provides a detailed review of the evidence-base underpinning the major uses of PET-CT in clinical practice, which may be of value to a wide-range of individuals, including those directly involved with PET-CT and to a much larger group with limited exposure, but for whom a précis of the current state-of-play may help inform other radiology and multidisciplinary team (MDT) work; the second purpose is as a companion to revised guidelines on evidence-based indications for PET-CT in the UK (being published concurrently) providing a detailed commentary on new indications with a summary of emerging data supporting these additional clinical uses of the technique.

Odorous gaseous emissions as influence by process condition for the forced aeration composting of pig slaughterhouse sludge.

Compost sustainability requires a better control of its gaseous emissions responsible for several impacts including odours. Indeed, composting odours have stopped the operation of many platforms and prevented the installation of others. Accordingly, present technologies collecting and treating gases emitted from composting are not satisfactory and alternative solutions must be found. Thus, the aim of this paper was to study the influence of composting process conditions on gaseous emissions. Pig slaughterhouse sludge mixed with wood chips was composted under forced aerationin 300 L laboratory reactors. The process conditions studied were: aeration rate of 1.68, 4.03, 6.22, 9.80 and 13.44 L/h/kg of wet sludge; incorporation ratio of 0.55, 0.83 and 1.1 (kg of wet wood chips/kg of wet sludge), and; bulking agent particles size of <10, 10<20 and 20<30 mm. Out-going gases were sampled every 2 days and their composition was analysed using gas chromatography coupled with mass spectrometry (GC-MS). Fifty-nine compounds were identified and quantified. Dividing the cumulated mass production over 30 days of composting, by odour threshold, 9 compounds were identified as main potential odour contributors: hydrogen sulphide, trimethylamine, ammonia, 2-pentanone, 1-propanol-2-methyl, dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide and acetophenone. Five gaseous compounds were correlated with both aeration rate and bulking agent to waste ratio: hydrogen sulphide, trimethylamine, ammonia, 2-pentanone and 1-propanol-2-methyl. However, dropping the aeration rate and increasing the bulking agent to waste ratio reduced gaseous odour emissions by a factor of 5-10, when the required threshold dilution factor ranged from 10(5) to 10(6), to avoid nuisance at peak emission rates. Process influence on emissions of dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide were poorly correlated with both aeration rate and bulking agent to waste ratio as a reaction with hydrogen sulphide was suspected. Acetophenone emissions originated from the wood chips. Olfactory measurements need to be correlated to gaseous emissions for a more accurate odour emission evaluation.

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.

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

Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology.

OBJECTIVE: The purpose of these guidelines is to offer to the nuclear medicine team a framework that could prove helpful in daily practice. These guidelines contain information related to the indications, acquisition, processing and interpretation of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) in paediatric oncology. The Oncology Committee of the European Association of Nuclear Medicine (EANM) has published excellent procedure guidelines on tumour imaging with (18)F-FDG PET (Bombardieri et al., Eur J Nucl Med Mol Imaging 30:BP115-24, 2003). These guidelines, published by the EANM Paediatric Committee, do not intend to compete with the existing guidelines, but rather aim at providing additional information on issues particularly relevant to PET imaging of children with cancer. CONCLUSION: The guidelines summarize the views of the Paediatric Committee of the European Association of Nuclear Medicine. They should be taken in the context of "good practice" of nuclear medicine and of any national rules, which may apply to nuclear medicine examinations. The recommendations of these guidelines cannot be applied to all patients in all practice settings. The guidelines should not be deemed inclusive of all proper procedures or exclusive of other procedures reasonably directed to obtaining the same results.

Zeolite (clinoptilolite) as feed additive to reduce manure mineral content.

Clinoptilolite (a species of zeolite) as grower hog feed additive can potentially improve nutrient ingestion and lower manure nutrient levels. A first objective was to establish the optimal particle size of the zeolite powder, as a fine size increases the adsorption surface while a coarse size can facilitate handling. The second objective tested the effect of feeding zeolite on manure nutrient levels. For the first objective, three zeolite powders (250-500 microm; 50-250 microm, and 50-500 microm) were exposed to an NH(4)(+) solution under a pH of either 7.0 or 2.0. The resulting solutions were tested for cation exchange. A commercial zeolite was also tested for the pH of 2.0 to evaluate zeolite stability. At 0%, 5% and 10% humidity, the same three particle size powders were subjected to shear tests to determine the zeolite's angle of friction. For the second objective using metabolic cages, female hogs were subjected to one of four rations (a control and three with zeolite) while collecting and analyzing their manures. For the first objective, the coarse particle zeolite performed best, adsorbing 158 and 123 Cmol(+)/kg of NH(4)(+) under neutral and acid pH, respectively, and releasing an equivalent amount of minerals only under neutral pH. The commercial zeolite with less clinoptilolite released more Al, Fe, Cu and Pb, showing less stability. The high internal angle of friction of zeolite did not vary with particle size and moisture, indicating funnel flow under gravity. For the second objective, hogs fed a zeolite diet produced manure with 15% and 22% less N and P, respectively, and demonstrated a better feed conversion, although not statistically significant (P>0.05). These results show that there is some potential in using high quality clinoptilolite in the ration of grower hogs.

18Flurodeoxyglucose positron emission tomography in the localization of ectopic ACTH-secreting neuroendocrine tumours.

OBJECTIVE: Neuroendocrine tumours (NET) are a rare cause of Cushing's syndrome. These tumours can be very small and therefore difficult to identify. Current localization techniques include CT, MRI and radioisotope scanning, but in a proportion of cases the NET remains occult. Positron emission tomography (PET) scanning, is a relatively new imaging modality that is increasingly used to detect and monitor lesions with high metabolic activity. We report on the use of PET scanning in the evaluation of the ectopic ACTH syndrome. PATIENTS: Three patients with ectopic ACTH-dependent Cushing's syndrome with varying difficulty in NET localization are included in the report. MEASUREMENT: Positron emission tomography scanning using 18flurodeoxyglucose (FDG) identifies tissue with high metabolic activity. 18FDG-PET scanning was used in each of these patients and the imaging is presented along with biochemical data. RESULTS: In each case the NET was easily identified using 18FDG-PET, aiding clinical decision making and therapeutic outcome. A cure was identified by clinical resolution of symptoms and undetectable ACTH levels postsurgery. CONCLUSIONS: 18FDG-PET assisted in localizing small metabolically active NETs, suggesting this imaging modality may have a useful role in identifying NET causing Cushing's syndrome as a result of ectopic ACTH production.

Zinc and copper uptake by plants under two transpiration rates. Part II. Buckwheat (Fagopyrum esculentum L.).

To evaluate the environmental risks of irrigating crops with treated wastewater, a study was undertaken to quantify heavy metal uptake by 4-week old buckwheat (Fagopyrum esculentum L.) plants during 18 days of irrigation with 8 different Cu and Zn solutions under two transpiration rates (TR). At 4 weeks, potted buckwheat plants were transferred into one of the two growth chambers, offering either a high or low vapour pressure deficit (VDP) for, respectively, a high or low TR. Triplicate pots received one of the 8 irrigation treatments containing one of two Zn levels (0 and 25 mg/L) combined with one of four Cu levels (0, 5, 10 and 15 mg/L). Daily TR were measured by weighing the evapo-transpired water lost from the planted pot, less was the evaporation loss measured from triplicate non-planted pots. After 0, 6, 12 and 18 days of treatment, the stems and leaves of three randomly selected plants were harvested and after 18 days, the roots were harvested to determine Cu and Zn uptake. The treatments did not affect TR in terms of dry plant mass, indicating the absence of toxic effects. Irrigating with Zn, without Cu, increased dry biomass production, whereas the lowest biomass occurred with 15 and 30 mg/L of Cu with and without 25 mg/L of Zn, respectively, because higher applications of heavy metal significantly reduced soil pH. Plant Cu and Zn uptake increased with TR. With higher levels of Cu, Zn uptake by buckwheat was significantly reduced, while Zn had a slight but non-significant impact on Cu uptake. Previously and in a study exposing wheat plants to the same conditions, Cu significantly increased Zn uptake, while Zn had a slight but insignificant negative effect on Cu uptake. The buckwheat roots contained the greatest levels of Cu and Zn, indicating their role in moderating heavy metal uptake. Also, both Cu and Zn had a synergetic effect on each other in terms of root levels, and a similar observation was made in the earlier similar experiment using wheat plants. Irrigating a buckwheat crop with treated wastewater, with more natural Cu and Zn levels of 0.08 mg/L, could be quite beneficial without endangering the quality of the crop and acidifying the soil pH. The most concentrated experimental solutions contained 300 times more Cu and Zn, to obtain measurable differences.

Zinc and copper uptake by plants under two transpiration rates. Part I. Wheat (Triticum aestivum L.).

To evaluate the environmental risk of irrigating crops with treated wastewater, an experiment was conducted using two growth chambers, each offering a different vapour pressure deficit (VPD) for high and low transpiration rates (TR), respectively. One of the two sets of 24 pots planted with 6 week old wheat (Triticum aestivum L.), was placed in each growth chamber, and irrigated in triplicates for 20 days with 8 Zn and Cu solutions (0 and 25 mg Zn/L combined with 0, 5, 15 and 30 mg Cu/L). Water losses from planted and non-planted pots served to measure evapo-transpiration and evaporation, respectively. Pots were monitored for Cu and Zn uptake by collecting three plants (shoot and grain)/pots after 0, 10 and 20 days, and roots in each pot after 20 days, and analyzing these plant parts for dry mass, and Cu and Zn levels. Transpiration rate was not affected by any Cu/Zn treatment, but Cu and Zn uptake increase with the time, irrigation solution level and higher TR, with the roots retaining most Cu and Zn, compared to the shoot followed by the grain. For the shoot and grain, Cu had a significant synergetic effect on Zn uptake, when Zn had slight but insignificant antagonistic effects on Cu uptake. For the roots, Cu and Zn had significant synergetic effect on each other. Regression equations obtained from the data indicate that Cu and Zn levels normally found in treated wastewater (0.08 mg/L) are 300 times lower than those used for the most concentrated experimental solutions (30 and 25 mg/L, respectively) and may, on a long term basis, be beneficial rather than toxic to wheat plants and do not acidify soil pH.

Single particle multichannel bio-aerosol fluorescence sensor.

We describe a prototype low-cost multi-channel aerosol fluorescence sensor designed for unattended deployment in medium to large area bio-aerosol detection networks. Individual airborne particles down to ~1mum in size are detected and sized by measurement of light scattered from a continuous-wave diode laser (660nm). This scatter signal is then used to trigger the sequential firing of two xenon sources which irradiate the particle with UV pulses at ~280 nm and ~370 nm, optimal for excitation of bio-fluorophores tryptophan and NADH (nicotinamide adenine dinucleotide) respectively. For each excitation wavelength, fluorescence is detected across two bands embracing the peak emissions of the same bio-fluorophores. Current measurement rates are up to ~125 particles/s, corresponding to all particles for concentrations up to 1.3 x 104 particles/l. Developments to increase this to ~500 particles/s are in hand. Device sensitivity is illustrated in preliminary data recorded from aerosols of E.coli, BG spores, and a variety of non-biological materials.

The impact of PET scanning on management of paediatric oncology patients.

PURPOSE: Limited information is available on the use of positron emission tomography (PET) in paediatric oncology. The aim of this study was to review the impact of PET on the management of paediatric patients scanned over a 10-year period. METHODS: One hundred and sixty-five consecutive oncology patients aged 11 months to 17 years were included. Two hundred and thirty-seven scans were performed. Diagnoses included lymphoma (60 patients), central nervous system (CNS) tumour (59), sarcoma (19), plexiform neurofibroma with suspected malignant change (13) and other tumours (14). A questionnaire was sent to the referring clinician to determine whether the PET scan had altered management and whether overall the PET scan was thought to be helpful. RESULTS: One hundred and eighty-nine (80%) questionnaires for 126 patients were returned (63 relating to lymphoma, 62 to CNS tumours, 30 to sarcoma, 16 to plexiform neurofibroma and 18 to other tumours). PET changed disease management in 46 (24%) cases and was helpful in 141 (75%) cases. PET findings were verified by histology, clinical follow-up or other investigations in 141 cases (75%). The returned questionnaires indicated that PET had led to a management change in 20 (32%) lymphoma cases, nine (15%) CNS tumours, four (13%) sarcomas, nine (56%) plexiform neurofibromas and four (22%) cases of other tumours. PET was thought to be helpful in 47 (75%) lymphoma cases, 48 (77%) CNS tumours, 24 (80%) sarcomas, 11 (69%) neurofibromas and 11 (61%) cases of other tumours. PET findings were verified in 44 (70%) lymphoma cases, 53 (85%) CNS tumours, 21 (70%) sarcomas, 12 (75%) neurofibromas and 11 (61%) other tumour cases. CONCLUSION: PET imaging of children with cancer is accurate and practical. PET alters management and is deemed helpful (with or without management change) in a significant number of patients, and the results are comparable with the figures published for the adult oncology population.

The role of positron emission tomography in the management of colorectal cancer.

Positron emission tomography (PET) is a functional imaging modality that has made the transition from the research environment to the clinical environment over the last 10 years. Its major role is in the field of oncology where it is being used increasingly in the management of several tumour types including colorectal cancer. This review aims to outline the current and future role of PET scanning in the field of colorectal cancer.

Comparison of sestamibi, thallium, echocardiography and PET for the detection of hibernating myocardium.

The detection of hibernating myocardium is important because revascularisation results in improved function and prognosis in patients with hibernation but not in those with non-viable myocardium. The primary aim of this study was to compare the diagnostic accuracy of four techniques with respect to hibernation in the same study population with 6-12 months of follow-up. Twenty-five males underwent rest-stress sestamibi and delayed (>18 h) thallium scintigraphy, high-dose dobutamine stress echocardiography and nitrogen-13 ammonia/fluorine-18 fluorodeoxyglucose (NH(3)/FDG) positron emission tomography (PET). The pre-operative ejection fraction was 36.2% (+/-7.3%). Follow-up was 8.1 (+/-2.8) months. Using postoperative improvement in wall motion on echocardiography as the gold standard, 6/34 dysfunctional vascular territories were hibernating. The mean uptake of all tracers was significantly higher in hibernating than in non-viable territories ( P<0.05). Normal perfusion or mismatch on PET (FDG>NH(3) uptake) and the pattern of response to dobutamine on echocardiography were also predictive of recovery ( P<0.001 and P=0.02 respectively). Univariate logistic regression identified sestamibi, ammonia and FDG as independent predictors of hibernation. FDG-PET was, however, the only independent predictor using multivariate analysis. The nuclear techniques had high negative predictive values (NPV) of >or=95% but lower positive predictive values (PPV) of 45%-75% as compared with echocardiography, which had an NPV of 87% and a PPV of 100%. PET was the most powerful predictor of hibernation although the combination of a technique with a high PPV (echocardiography) and a high NPV (PET or sestamibi) may represent the optimal clinical choice.

Imaging of abdominal infection using 99m Tc stannous fluoride colloid labelled leukocytes.

Radiolabelling of leukocytes using labelled phagocytosed technetium-99m (99mTc) colloidal radiopharmaceuticals has been reported as a method for imaging infection. This in vivo study compares the use of leukocytes labelled using 99mTc stannous fluoride colloid with leukocytes labelled using indium-111 (111In) oxinate. A total of 26 patients (10 male, 16 female; mean age 52 years, range 23-88 years) referred for the investigation of possible infection were studied using both leukocyte labelling methods simultaneously. Images were acquired 4h and 24h after re-injection of the labelled cells. The images were evaluated qualitatively by two nuclear medicine physicians. The results show a high degree of concordance between the techniques: 11 of the 28 images showed a focus of leukocyte accumulation with both techniques at 24h, and 13 out of 28 showed a normal appearance at 24h with both methods. In four cases the results were discordant; the 99mTc stannous fluoride colloid labelled leukocytes gave a false positive appearance at 24h in three patients and a false negative in one. In conclusion, colloid labelling of leukocytes offers a sensitive method for the detection of infective foci coupled with the high resolution imaging offered by 99mTc. It has the advantage over other in vitro labelling methods of being a simpler, non-labour-intensive procedure employing whole blood, and its use should be considered by departments that have limited facilities for in vitro leukocyte labelling.