3-T magnetic resonance-guided high-intensity focused ultrasound (3 T-MR-HIFU) for the treatment of pain from bone metastases of solid tumors.

INTRODUCTION: Bone metastases (BM) are still the main cause of morbidity and mortality in cancer patients, not only because of their complications, defined as skeletal-related events (SREs), but also because of the negative impact bone pain has on quality of life (QoL) and survival, especially when opioid analgesics and locoregional treatments fail. MATERIALS AND METHODS: A single-center prospective study was carried out on 12 patients with symptomatic BM treated with MRI-guided focused ultrasound (MR-HIFU). The primary endpoint was the effectiveness of MR-HIFU in reducing current and breakthrough cancer pain (BTCP) scores. The main secondary aims were the evaluation of circulating markers at different time-points and their relation to pain and procedure efficacy. Other secondary objectives included temporal evolution of pain response, evaluation of QoL, and side effects of the treatment. Descriptive statistics were used to evaluate primary and secondary endpoints. Questionnaires on pain and QoL completed at baseline and at 30 days were compared using appropriate statistical tests with exploratory intent. RESULTS: MR-HIFU was successfully completed in all 12 patients enrolled between September 2015 and December 2018. On day 30, 6 (50.0%) patients showed a complete response of current pain and 6 a partial response, while 5 (41.7%) obtained a complete BTCP response. A partial response of BM evaluated by MD Anderson criteria was obtained in 9 (81.8%) patients. Only one patient progressed in the target lesion after MR-HIFU. No treatment-related adverse events were recorded. Bone turnover markers CTX/RANK-L (P) do not demonstrate any significant change with the pain or BM response. CONCLUSION: In our patients, targeted therapy of painful BM with MRI-guided focused ultrasound ablation was safe and showed encouraging early-onset and functional results.

IntegoTM infusion system: cost effectiveness analysis focusing on dosimetry, sterility and management.

BACKGROUND: Healthcare providers across Europe are facing an ever-growing demand in clinical PET referrals. Currently, it is estimated that the administration of the PET tracer accounts for approximately 40% of the unitary PET procedure reimbursement (uPETr). Although the cost of PET/CT is highly dependent on the radiopharmaceutical cost itself, little is known about the economic impact of the utilized administration method and the repercussions on staff radiation exposure. Our objective was to evaluate the cost-effectiveness of automatic injection/fractionation system Intego™ (Bayer HealthCare, MEDRAD Europe, Netherlands) for istaff radiation exposure reduction and to validate its use with 18F-choline (FCH). METHODS: In order to validate Intego™ use with FCH we analyzed sterility, radioactivity fractionation accuracy and radiation protection for staff. We analyzed Intego™ impact on examination costs and its impact on organization efficiency. A cost-effectiveness analysis (CEA) was estimated as the incremental cost to reduce staff radiationexposure. RESULTS: According to our data, Intego™ ensures both sterility and accuracy of FCH doses' activity, reducing, at the same time, the exposure to radiation either whole body and at the extremities (94% and 75% respectively for the technicians and complete reduction for physicians). Intego™'s variable unit costs are higher than the SA (respectively 1.8% and 0.4% of PET reimbursement), while staff costs are significantly higher with SA (respectively 0.27% and 1.57% of unitary PET reimbursement [uPETr]). In our simulation, based on a 2,450 PET yearly output, the differential costs were slightly higher by using Intego™™ (+ 14%). The incremental cost-effectiveness ratio (ICER) was equal to 1.1, i.e. the healthcare provider pays an additional cost of 0.38% of uPETr to obtain a significant reduction of staff radiation exposure (-4.5 µS). CONCLUSIONS: Intego™, for its favorable results in terms of cost effectiveness, could be a useful tool in a nuclear medicine department, limiting the staff radiation exposure.

Cold pressor test using strain-gauge plethysmography.

This laboratory activity is designed to teach students how to measure forearm muscle blood flow (FBF) to describe the mechanisms of peripheral blood flow thermal regulation in healthy subjects. The cold pressor test (CPT) is the clinical procedure used in the experiment to induce arterial vasoconstriction. Strain-gauge plethysmography is applied on the patient's forearm to noninvasive monitor vasoconstriction effects on local blood perfusion and physiological parameters such as blood pressure (BP) and heart rate (HR). Patients with an altered peripheral vascular resistance (e.g., in hypertension) have different responses to the CPT from healthy subjects. To date, experimental evidence remains unexplained, as we do not know if the BP and HR increase is caused by a decrease in flow rate or an increase in peripheral vascular resistance during the test. To clarify this situation, we have to quantify the parameter we assume is being conditioned by the regulatory physiological intervention, i.e., peripheral vascular resistance. Peripheral vascular resistance quantification can be calculated as the ratio between muscle flow and mean arterial pressure. Students will learn how to apply the instrumental procedure to collect and analyze data before, during, and after the CPT and to describe the physiological responses of the peripheral vascular system to external stressors. They will also learn how to distinguish healthy from pathological responses on the basis of how sympathetic nervous system reactions influence the biomechanics of peripheral vessels.

Association between Pre-Treatment Biological Indicators and Compliance to Neoadjuvant/Perioperative Chemotherapy in Operable Gastric Cancer.

BACKGROUND AND AIMS: Perioperative treatment is currently the gold standard approach in Europe for locally advanced gastric cancer (GC). Unfortunately, the phenomenon of patients dropping out of treatment has been frequently observed. The primary aims of this study were to verify if routine blood parameters, inflammatory response markers, sarcopenia, and the depletion of adipose tissues were associated with compliance to neoadjuvant/perioperative chemotherapy. METHODS AND STUDY DESIGN: Blood samples were considered before the first and second cycles of chemotherapy. Sarcopenia and adipose indices were calculated with a CT scan before starting chemotherapy and before surgery. Odds ratios (OR) from univariable and multivariable models were calculated with a 95% confidence interval (95% CI). RESULTS: A total of 84 patients with locally advanced GC were identified between September 2010 and January 2021. Forty-four patients (52.4%) did not complete the treatment according to the number of cycles planned/performed. Eight patients (9.5%) decided to suspend chemotherapy, seven patients (8.3%) discontinued because of clinical decisions, fourteen patients (16.7%) discontinued because of toxicity and fifteen patients (17.9%) discontinued for miscellaneous causes. Seventy-nine (94%) out of eighty-four patients underwent gastrectomy, with four patients having surgical complications, which led to a suspension of treatment. Sarcopenia was present in 38 patients (50.7%) before chemotherapy began, while it was present in 47 patients (60%) at the CT scan before the gastrectomy. At the univariable analysis, patients with basal platelet to lymphocyte ratio (PLR) ≥ 152 (p = 0.017) and a second value of PLR ≥ 131 (p = 0.007) were more frequently associated with an interruption of chemotherapy. Patients with increased PLR (p = 0.034) compared to the cut-off were associated with an interruption of chemotherapy, while patients with increased monocytes between the first and second cycles were associated with a lower risk of treatment interruption (p = 0.006); patients who underwent 5-fluorouracil plus cisplatin or oxaliplatin had a higher risk of interruption (p = 0.016) compared to patients who underwent a 5-fluorouracil plus leucovorin, oxaliplatin and docetaxel (FLOT) regimen. The multivariable analysis showed a higher risk of interruption for patients who had higher values of PLR compared to the identified cut-off both at pretreatment and second-cycle evaluation (OR: 5.03; 95% CI: 1.34-18.89; p = 0.017) as well as for patients who had a lower PLR than the identified cut-off at pretreatment evaluation and had a higher PLR value than the cut-off at the second cycle (OR: 4.64; 95% CI: 1.02-21.02; p = 0.047). Becker regression was neither affected by a decrease of sarcopenia ≥ 5% (p = 0.867) nor by incomplete compliance with chemotherapy (p = 0.281). CONCLUSIONS: Changes in PLR values which tend to increase more than the cut-off seem to be an immediate indicator of incomplete compliance with neoadjuvant/perioperative treatment. Fat loss and sarcopenia do not appear to be related to compliance. More information is needed to reduce the causes of interruption.

Prognostic and Predictive Role of Body Composition in Metastatic Neuroendocrine Tumor Patients Treated with Everolimus: A Real-World Data Analysis.

Neuroendocrine tumors (NETs) are rare neoplasms frequently characterized by an upregulation of the mammalian rapamycin targeting (mTOR) pathway resulting in uncontrolled cell proliferation. The mTOR pathway is also involved in skeletal muscle protein synthesis and in adipose tissue metabolism. Everolimus inhibits the mTOR pathway, resulting in blockade of cell growth and tumor progression. The aim of this study is to investigate the role of body composition indexes in patients with metastatic NETs treated with everolimus. The study population included 30 patients with well-differentiated (G1-G2), metastatic NETs treated with everolimus at the IRCCS Romagnolo Institute for the Study of Tumors (IRST) "Dino Amadori", Meldola (FC), Italy. The body composition indexes (skeletal muscle index [SMI] and adipose tissue indexes) were assessed by measuring on a computed tomography (CT) scan the cross-sectional area at L3 at baseline and at the first radiological assessment after the start of treatment. The body mass index (BMI) was assessed at baseline. The median progression-free survival (PFS) was 8.9 months (95% confidence interval [CI]: 3.4-13.7 months). The PFS stratified by tertiles was 3.2 months (95% CI: 0.9-10.1 months) in patients with low SMI (tertile 1), 14.2 months (95% CI: 2.3 months-not estimable [NE]) in patients with intermediate SMI (tertile 2), and 9.1 months (95% CI: 2.7 months-NE) in patients with high SMI (tertile 3) (p = 0.039). Similarly, the other body composition indexes also showed a statistically significant difference in the three groups on the basis of tertiles. The median PFS was 3.2 months (95% CI: 0.9-6.7 months) in underweight patients (BMI ≤ 18.49 kg/m2) and 10.1 months (95% CI: 3.7-28.4 months) in normal-weight patients (p = 0.011). There were no significant differences in terms of overall survival. The study showed a correlation between PFS and the body composition indexes in patients with NETs treated with everolimus, underlining the role of adipose and muscle tissue in these patients.

[18F]F-PSMA-1007 Radiolabelling without an On-Site Cyclotron: A Quality Issue.

Radiopharmaceuticals targeting the prostate-specific membrane antigen (PSMA) has become the gold standard for PET imaging of prostate cancer. [68Ga]Ga-PSMA-11 has been the forerunner but a [18F]F-PSMA ligand has been developed because of the intrinsic advantages of Fluorine-18. Fluorine-18 labelled compounds are usually prepared in centers with an on-site cyclotron. Since our center has not an on-site cyclotron, we decided to verify the feasibility of producing the experimental 18F-labelled radiopharmaceutical [18F]F-PSMA-1007 with [18F]F- from different external suppliers. A quality agreement has been signed with two different suppliers, and a well-established and correctly implemented quality assurance protocol has been followed. The [18F]F- was produced with cyclotrons, on Nb target, but with different beam energy and current. Extensive validation of the [18F]F-PSMA-1007 synthesis process has been performed. The aim of this paper was the description of all the quality documentation which allowed the submission and approval of the Investigational Medicinal Product Dossier (IMPD) to the Competent Authority, addressing the quality problems due to different external suppliers. The result indicates that no significant differences have been found between the [18F]F- from the two suppliers in terms of radionuclidic and radiochemical purity and [18F]F- impacted neither the radiochemical yield of the labelling reaction nor the quality control parameters of the IMP [18F]F-PSMA-1007. These results prove how a correct quality assurance system can overcome some Regulatory Authorities issue that may represent an obstacle to the clinical use of F-18-labelled radiopharmaceuticals without an on-site cyclotron.

Radiological aspects of CO2 peripheral DSA: Preliminary analysis on the dedicated protocols.

OBJECTIVES: Thanks to its lack of allergic reactions and renal toxicity, CO2 represents an alternative to iodine as a contrast medium for peripheral subtraction angiography. Since CO2 has a lower and negative contrast than iodine, postprocessing DSA and stacking are mandatory. So, it seems that higher doses than traditional iodine angiography are required. We addressed the dosimetric aspects of CO2 angiography for two different commercial DSA-apparatus. MATERIALS AND METHODS: Two different radiological suites were analyzed by recreating the same setup on all the apparatuses: we used a PMMA slabs phantom with a MPD Barracuda dosimeter on its side to collect all radiological parameters. RESULTS: Results show that the irradiation parameters were left completely unchanged between the traditional and CO2 angiographic programs. CONCLUSIONS: This leads to thinking that these CO2 protocols do not operate on the X-ray emission, but only differ on image manipulation. The possibility of improvements by changing radiological parameters are still not explored and really promising.

Decrease in patient radiation exposure by a tantalum filter during electrophysiological procedures.

AIM: Minimization of X-ray exposure remains a primary issue in cardiac electrophysiology. The effectiveness of X-ray beam filtration during cardiac electrophysiological procedures was therefore studied, using a 0.05-mm-thick tantalum (Ta) foil, as a filter on the primary X-ray beam, to reduce the patient dose without degradation of image quality. METHOD: Preliminary tests were made on a phantom developed with polymethylmethacrylate, catheters, and guide wires. The filter was then used in patients during cardiac procedures. Identical patient images were obtained with and without the Ta filter insertion and the ratio between image quality and patient dose was evaluated. Changes in patient dose and signal-to-noise ratio, as image quality index were measured on the phantom and in patients. RESULTS AND CONCLUSIONS: When the Ta filter was used, the mean effective individual patient dose decreased by 3 to 40% (mean reduction = 27%), with no perceivable difference in image quality estimated by electrophysiologists. This Ta filter may be useful to limit the radiation exposure of patients and operators during cardiac procedures.

Quantitative accuracy of 177Lu SPECT imaging for molecular radiotherapy.

The purpose of this study is to investigate the optimal reference geometry for gamma camera calibration. Yet another question of interest was to assess the influence of the number of 3D Ordered Subsets Expectation Maximization (3D-OSEM) updates on activity quantification for SPECT imaging with 177Lu. The accuracy of 177Lu activity quantification was assessed both in small and in large objects. Two different reference geometries, namely a cylindrical homogeneous phantom and a Jaszczak 16 ml sphere surrounded by cold water, were used to determine the gamma camera calibration factor of a commercial SPECT/CT system. Moreover, the noise level and the concentration recovery coefficient were evaluated as a function of the number of 3D-OSEM updates by using the SPECT/CT images of the reference geometry phantoms and those of a cold Jaszczak phantom with three hot spheres (16ml, 8ml and 4ml), respectively. The optimal choice of the number of 3D-OSEM updates was based on a compromise between the noise level achievable in the reconstructed SPECT images and the concentration recovery coefficients. The quantitative accuracy achievable was finally validated on a test phantom, where a spherical insert composed of two concentric spheres was used to simulate a lesion in a warm background. Our data confirm and extend previous observations. Using the calibration factor obtained with the cylindrical homogeneous phantom and the Jaszczak 16 ml sphere, the recovered activity in the test phantom was underestimated by -16.4% and -24.8%, respectively. Our work has led us to conclude that gamma camera calibration performed with large homogeneous phantom outperforms calibration executed with the Jaszczak 16ml sphere. Furthermore, the results obtained support the assumption that approximately 50 OSEM updates represent a good trade-off to reach convergence in small volumes, meanwhile minimizing the noise level.

Preliminary Retrospective Analysis of Daily Tomotherapy Output Constancy Checks Using Statistical Process Control.

The purpose of this study was to retrospectively evaluate the results from a Helical TomoTherapy Hi-Art treatment system relating to quality controls based on daily static and dynamic output checks using statistical process control methods. Individual value X-charts, exponentially weighted moving average charts, and process capability and acceptability indices were used to monitor the treatment system performance. Daily output values measured from January 2014 to January 2015 were considered. The results obtained showed that, although the process was in control, there was an out-of-control situation in the principal maintenance intervention for the treatment system. In particular, process capability indices showed a decreasing percentage of points in control which was, however, acceptable according to AAPM TG148 guidelines. Our findings underline the importance of restricting the acceptable range of daily output checks and suggest a future line of investigation for a detailed process control of daily output checks for the Helical TomoTherapy Hi-Art treatment system.

MR Spectroscopy in Prostate Cancer: New Algorithms to Optimize Metabolite Quantification.

Prostate cancer (PCa) is the most common non-cutaneous cancer in male subjects and the second leading cause of cancer-related death in developed countries. The necessity of a non-invasive technique for the diagnosis of PCa in early stage has grown through years. Proton magnetic resonance spectroscopy (1H-MRS) and proton magnetic resonance spectroscopy imaging (1H-MRSI) are advanced magnetic resonance techniques that can mark the presence of metabolites such as citrate, choline, creatine and polyamines in a selected voxel, or in an array of voxels (in MRSI) inside prostatic tissue. Abundance or lack of these metabolites can discriminate between pathological and healthy tissue. Although the use of magnetic resonance spectroscopy (MRS) is well established in brain and liver with dedicated software for spectral analysis, quantification of metabolites in prostate can be very difficult to achieve, due to poor signal to noise ratio and strong J-coupling of the citrate. The aim of this work is to develop a software prototype for automatic quantification of citrate, choline and creatine in prostate. Its core is an original fitting routine that makes use of a fixed step gradient descent minimization algorithm (FSGD) and MRS simulations developed with the GAMMA libraries in C++. The accurate simulation of the citrate spin systems allows to predict the correct J-modulation under different NMR sequences and under different coupling parameters. The accuracy of the quantifications was tested on measurements performed on a Philips Ingenia 3T scanner using homemade phantoms. Some acquisitions in healthy volunteers have been also carried out to test the software performance in vivo.

Passive aortic counterpulsation: biomechanical rationale and bench validation.

Aortic counterpulsation (IABP) consists in an ECG-controlled forced deflation and inflation of a balloon positioned in the aorta. The device is designed to decrease the ventricular afterload during systole and to increase the coronary driving pressure during diastole. In biomechanical terms, the IABP improves the mechanical matching between the pump and the load, facilitating the transfer of ventricular energy. This paper describes a completely passive aortic counterpulsation solution, with an intra-aortic balloon without a pumping system, designed to improve the mechanical matching between the ventricle and the artery at very low cost and complexity. The only requirement is an external reservoir to amplify the balloon pulsations due to physiologic arterial pressure pulse. Using a cardiovascular simulator and changing the reservoir pressure, a systolic not negligible (7.8ml) gas volume exchange between the intra-aortic balloon and the reservoir was measured. The same cardiovascular simulator was used to demonstrate an increase in stroke volume in three conditions of progressive ventricular failure, by detecting a change in systolic and diastolic arterial pressures and stroke volume (SV). The maximal arterial pressure always decreased and the diastolic pressure increased. The SV increased up to 7.8%, demonstrating an arterial elastance reduction and better ventricular-aortic mechanical matching and energy transfer.