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The development of traceable new methodologies to quantify elemental air pollutants in particulate matter (PM) supports modernization of methods used in air quality monitoring networks in Europe. In the framework of the EURAMET EMPIR AEROMET II project, the combination of cascade impactor aerosol sampling and total reflection X-ray fluorescence elemental spectroscopy (TXRF) was investigated. This technique requires a traceable calibration based on reference samples. This paper describes a new, simple and effective method to produce such reference samples using flexible, reusable, and low-cost parylene C shadow masks, fabricated by photolithographic steps. These shadow masks can be used to produce reference samples that mimic the Dekati cascade impactor's deposition patterns by applying as-prepared micro stencils to 30 mm acrylic substrates and evaporating a reference material (Ti) in arrangements of thin circular dots. The highly flexible direct patterning of acrylic discs with reference material, otherwise impossible with conventional photolithography, allows multiple reusing of the same micro stencils. The aspect ratios of the dots could be repeated with an error less than 4%. A first set of standard reference samples for the 13 stages of the Dekati cascade impactor was produced and preliminary TXRF measurements of the deposited Ti masses were performed. The centricity of the deposition patterns turned out to be an important parameter for the quality of the TXRF results. The parylene mask technology for the production of reference samples turns out to be a promising new approach for the traceable calibration of TXRF spectrometers for the quantification of element concentrations in environmental aerosol samples but, due to its great versatility, it could be used for several other micropatterning applications on conventional and unconventional substrates.

PET scanners require routine monitoring and quality control (QC) to ensure proper scanner performance. QC helps to ensure that PET equipment performs as specified by the manufacturer and that there have not been significant changes in the system response since acceptance. In this work we describe the maintenance history and we report on the results obtained from the PET system QC testing program over 5 years at two centers, both utilizing a Siemens Biograph 16 HiRez PET/CT system. QC testing programs were based on international standards and included the manufacturer’s daily QC, monthly uniformity and sensitivity, quarterly cross-calibration and annual resolution and image quality. For the Winnipeg and Novara sites, two and one PET detector blocks have been replaced, respectively. Neither system has had other significant PET system related hardware replacements. The manufacturer’s suggested daily QC was sensitive to detecting problems in the function of PET detector elements. The same test was not sensitive for detecting long term drifts in the systems: the Novara system observed a significant deterioration over five years of testing in the sensitivity which exhibited a decrease of 16% as compared to its initial value measured at system installation. The measure of the energy spectrum, showed that the 511 keV photopeak had shifted to a position of 468 keV. This shift was corrected by having service personnel perform a complete system calibration and detector block setup. We recommend including tests of system energy response and of sensitivity as part of a QC program since they can provide useful information on the actual performance of the scanner. A modification of the daily QC test by the manufacturer is suggested to monitor the long term stability of the system. Image quality and spatial resolution tests have proven to be of limited value for monitoring the system over time.

[ 153 Sm]Sm-EDTMP is a radiopharmaceutical used in palliation cares of bone metastases. The purpose of this study is to provide an explicit description of [ 153 Sm]Sm-EDTMP pharmacokinetics, adopting a simple three-compartmental model with the analytical expressions calculating the rate constants and determining biodistribution parameters, like radiopharmaceutical uptake and clearance. This biokinetic model allowed us to calculate on an individual basis the dose to bone surface and to red bone marrow and to assess the degree of variability in dosimetric parameters using a fixed administered activity based only on patient weight. In this study twenty patients were enrolled and were treated with [ 153 Sm]Sm-EDTMP, administering a fixed activity per kilogram (37 MBq/kg); blood and urine samples were collected during 24 h post treatment. The median value of the administered activity was 2.7 GBq. Blood clearance confirmed that an aliquot of [ 153 Sm]Sm-EDTMP rapidly localizes and is retained in bone, while the remainder is rapidly cleared from the blood pool by the urinary system. Our data show a bi-exponential clearance from blood: the rapid component has a half life median value of 6 min (range: 2–24 min), while the slow one has a half life median value of 1.4 h (range: 0.6–5.8 h). Median value of the urinary excretion is 40 (range: 3–75) % of the administered activity. Our model shows the behaviour of a tracer which is distributed in the extracellular space of the body, localized in the skeleton and excreted via glomerular filtration. Half life median values of [ 153 Sm]Sm-EDTMP transferring between compartments, T 1/2 (blood→ECF), T 1/2 (ECF→blood) are 7.4 (range: 1.9–37) and 48 (range: 8–408) min, respectively. Median values of half lives of [ 153 Sm]Sm-EDTMP clearance through the urine and of uptake into bone are 1.0 (range: 0.1–6.0) and 1.6 (range: 0.6–9.0) h, respectively. Median value of red marrow absorbed dose is 2.1 (range: 0.7–3.5) Gy and 0.8 (range: 0.3–2.1) Gy/GBq, while median value of bone surface absorbed dose is 11.5 Gy (range: 5.0–18.4) and 4.4 (range: 2.3–14.3) Gy/GBq. It is remarkable that there is a really great biological variability within patients, especially considering the excreted activity. The cumulated activity in bone and red marrow doses were significantly higher in prostate cancer, where metastatic bone lesions are osteoblastic, than in breast cancer where metastatic bone lesions are osteolytic or mixed (lytic/blastic). The relevant biological variability in biodistribution and metabolism of [ 153 Sm]Sm-EDTMP suggests that the fixed administered activity based on patient weight is not sufficient to optimize the treatment and a better optimization would be reached by using a predictive dosimetry tailored to individual patient characteristics.

Purpose To investigate the ArcCheck performances for PsQA of SBRT treatments and to find the better gamma analysis criteria. Methods Twelve spherical targets (radii from 4 mm to 15 mm) were simulated in a phantom consisting of the ArcCheck with the MultiPlug™ homogeneous RW3 insert. For each target a SBRT treatment was planned. The delivered doses were simultaneously measured by ArcCheck and gafchromic EBT3 films. The ArcCheck measurements in standard mode (Sm), were repeated in high density mode (HDm). PsQAs were performed using a local gamma index analysis (threshold 20%). Passing Rates (PR) of EBT3 films, ArcCheck Sm and HDm acquisitions were investigated as a function of DD%, DTA criteria and target dimensions. The correlation between ArcCheck and EBT3 film PR was stated and the better gamma criteria for ArcCheck PR was found by means of the maximization of Level Of Agreement with the film. Results The EBT3 films assessed optimal dose delivery accuracy with maximum deviations below the limit of 3%, close to the EBT3 uncertainty budget. For each of the reported methods the PR resulted significantly related to DTA, DD% and target dimension, with DTA criterion resulting the leading effect. Optimal gamma analysis criteria for EBT3 film resulted by combination of DTA = 1 mm and D%⩾3%, a PR threshold of 75% resulted predictive of clinical acceptable agreement in the target and dose falloff regions. The difference between the performances of ArcCheck Sm and HDm acquisition modes was not clinically relevant. The ArcCheck Sm and EBT3 film PR were significantly correlated between them. An optimal LOA Conclusions The ArcCheck resulted suitable for PsQA in SBRT treatments with properly selected local gamma criteria.

Purpose According to the EU directive 2013/59, the equipment used for computed tomography (CT) shall be able to inform the practitioner of relevant parameters for assessing the patient dose. Among them, the radiation output is usually displayed in terms of computed tomography dose index – CTDI [mGy]. The aim of this study was to measure the accuracy of the displayed CTDI100 for different manufacturers or models of CT and to assess the impact of acquisition parameters on CTDI100 accuracy. Methods 10 CT from 4 different manufacturers (16-slices n = 6, 32-slices n = 1, 64-slices n = 3) were included in the study. The accuracy of the displayed CTDI100 was checked with a dosimeter with traceable calibration. Reference values for the displayed CTDI100 were derived from the equipment’s manual. The impact of the CT model (16, 64, 128 slices), phantom size (head or body), kVp (80, 100, 120, 140 kVp) and primary collimation (from 1.25 to 40 mm, grouped in four level ⩽ 3, from 3 to ⩽ 10, from 10 to ⩽ 20, > 20 mm) on the accuracy of the displayed CTDI100, was assessed by a four-way factorial ANOVA. CT model, phantom size, kVp and primary collimation, were considered as independent variables (factors) and CTDI accuracy as the dependent variable. Results All the factors had a statistically significant impact on CTDI100 accuracy (p 0,05). In a head to head comparison, the lower accuracies were found on average for sixteen channels CT (10 ± 5%), for 80 KV (15 ± 11%) and for thick collimations (13 ± 7%), whilst no significant differences were found between head and body phantoms. Conclusions For sixteen channels CT and acquisition protocols involving the use of head phantom with low KV and thick primary collimation, the inaccuracies of the displayed CTDI can be higher than 20%, which is the suspension level indicated in the EC RP N.162 Publication for the accuracy of indicated dose parameters. This suggests the need of individual calibration of CT X-ray tubes by the manufacters and the necessity of including this check in the quality control programs for CT.

Introduction Point-spread-function (PSF) modelling seem to be very attractive to obtain superior image quality in [F-18] FDG oncological studies, nonetheless it is known to significantly increase noise variability. Purpose To evaluate the impact of PSF/TF on noise structure of iterative reconstructed (IR) images. Materials and methods An anthropomorphic phantom with [F-18] FDG clinical concentrations was acquired on Biograph-mCT (Siemens) and Discovery690 (General Electric) PET/CT scanners. Overall, 96 datasets were obtained by varying reconstruction modalities (RM = IR, TF, PSF, TF+PSF), frame (128,256), equivalent iterations number (IT = 63,270), and Gaussian filter (GF = 2, 4, 6 mm). To limit noise correlation in PET imaging, 6 groups of concentric ROIs (r = 8;10;13;16;19 mm) were drawn on 3 slices at liver level. Fixing slice and ROI size, the signal variation was defined: SV% = 100∗SD/M, were SD,M are standard deviation, mean among the mean count values found for the ROIs, respectively. Results SV decreases with ROI size and GF, and increases with IT. Moreover, SV depends on RM, but in different ways on the two PET scanners. For Biograph-mCT, highest and lowest SV were observed for PSF and TF and for GF = 2, 4, 6 mm mean(range) values were: 7.8%(5.1–10.6), 5.7%(3.1–8.5), 4.5%(2.5–6.7) and 4.5%(2.7–6.4), 3.8%(2.4–5.4), 3.2(2.2–4.5), respectively. For Discovery690, highest and lowest SV were observed for PSF+TF and IR and for GF = 2, 4, 6 mm the mean(range) values were: 8.3%(6.8–10.5), 8.1%(6.7–10.2), 7.9%(6.6–9.7) and 5.1%(3.5–8.2), 4.5%(3.1–7.0), 4.2%(3.2–6.2), respectively. Same trends are observed for the range of SV values. Conclusions The PET scanners of this study showed different behaviors of SV in relation to RM. Increased SV could lead to degradation of precision in quantitative oncological studies with [F-18] FDG for monitoring treatment response.

Introduction the skin of the hands of the nuclear medicine’s staff involved in preparation and manipulation of unsealed radiopharmaceuticals is the organ at highest risk for irradiation. The dose limit, to be applied to the average of 1 cm 2 of skin regardless the surface of the exposed area, is of difficult assessment. The ORAMED project identified the tip of the index of the non-dominant hand as the point of maximum exposure. Due to the high estimated proportion of workers liable to exceed the extremities annual dose limit (15–20%), the fingers dose monitoring is highly recommended especially in busy labs. Purpose To evaluate under routine operating conditions, in 3 nuclear medicine departments, the irradiation dose to the extremities of workers involved in the preparation of 99m Tc-radiopharmaceuticals. Materials and methods Two operators for each centre were monitored by using 4 TLD (LiF: Mg, Cu, P) for 2 weeks. For each single task the operational time and the manipulated activities were recorded. Results The mean daily 99m Tc activity manipulated was 56 GBq resulting in a mean dose equivalent values of: 38.5, 18.9, 5.4 and 63.7 microSv/GBq for the monitored hand positions: index tip of non-dominant, index base of non-dominant, wrist of non-dominant and index tip of dominant hand respectively. Conclusion Conversely to the ORAMED findings, the index fingertip of the dominant hand receives the highest dose. Based on the daily handled activities, the dose limit could be exceeded in 138 working days, thus confirming the concerns raised by many authors.

Introduction Nowadays interventional cardiac procedures are of concern for the relatively high doses delivered to patients. Purpose To estimate the effective dose (E), the organ doses (H t ) and the related risk for cancer induction in terms of radiation exposure-induced death (REID) in patients undergoing coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures with radial access. Materials and methods 65 patients underwent CA and PTCA interventions on a Philips Allura XPer FD10 angiographic equipment. For each patient, Xray tube voltage, projection, filtration, field dimensions and DAP were obtained by filming the monitor of the workstation during the entire procedure. E and H t were evaluated by means of the MonteCarlo code PCXMC that models radiation beam and transport in an anthropomorphic phantom, allowing also the evaluation of REID. Results Mean fluoroscopy time, DAP and E were: 3.1 min, 29.9 Gyxcm 2 , 9.1 mSv and 8.9 min, 60.9 Gyxcm 2 , 20.3 mSv for CA and PTCA, respectively; the correlation with DAP was very good in CA (r = 0.99) and in PTCA (r = 0.93). For both CA and PTCA, the most irradiated organs were lungs, oesophagus and red marrow, whose mean H t were 32.5 mSv, 30.7 mSv, 11.6 mSv for CA and 58.5 mSv, 66.7 mSv, 24.9 mSv for PTCA; the highest REIDs were for induction of leukemia (0.04% and 0.08%) and lung cancer (0.14% and 0.20%). Conclusions Cardiac interventional procedures with radial access improves patient compliance, reduces haemorrhagic complications compared to femoral access with comparable E and Ht values.

Purpose End Stage Kidney Disease patients are exposed to ionizing radiation during imaging studies. The variability in diagnostic imaging policies and the accompanying risk across Renal Units are unknown. We studied this variability at centre level and quantified the associated risks at patient level, by estimating the organ doses (H T ) and the Risk of exposure-induced cancer death (%) (REID). Materials and methods Fourteen nephrology departments enrolled 739 patients on hemodialysis (HD) and 486 kidney transplant patients (KTP), recording the details of the radiological procedures performed over one year. H T were derived using Montecarlo based simulation software for conventional diagnostic radiology procedures and for Computed Tomography. H T were derived using tabulated conversion factors for cardiac interventional radiology and nuclear medicine procedures. Results The average REID was 0.047 ± 0.12 % and the corresponding 5-years cancer risk attributable to ionizing radiation exposure was 1 every 424 patients. The median REID was 0.009% and the 3 rd quartile was 0.03%. The average REID was significantly higher in HD than in KTP (0.06 ± 0.13 i.e. 1:333 patients for 5-years vs 0.03 ± 0.09 i.e. 1:666 patients for 5-years; p F = 3.23; p Conclusion The excess cancer risk attributable to medical exposure is highly variable among centres (a tenfold variation), suggesting that protocols of individual patient’s follow up with medical imaging are not standardized. On average, KTP have a lower exposure than HD patients (a twofold variation). Disclosure None to declare.