The quarterly journal of nuclear medicine and molecular imaging : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of...最新文献

Background: The aim of this phantom study was to optimize the [⁶⁸Ga]Ga-PSMA PET/CT examination in terms of scan time duration and image reconstruction parameters, in combination with PSF and TOF modelling, in a digital Biograph Vision PET/CT scanner.

Methods: Three types of phantoms were used: 1) soft-tissue tumor phantom consisting of six spheres mounted in a torso phantom; 2) bone-lung tumor phantom; 3) resolution phantom. Phantom inserts were filled with activity concentrations (ACs) that were derived from clinical data. Phantom data were acquired in list-mode at one bed position. Images with emission data ranging from 30 to 210 s in 30-s increments were reconstructed from a reference image acquired with 3.5-min emission. Iterative image reconstruction (OSEM), point-spread-function (PSF) and time-of-flight (TOF) options were applied using different iterations, Gaussian filters, and voxel sizes. The criteria for image quality was lesion detectability and lesion quantification, evaluated as contrast-to-noise ratio (CNR) and maximum AC (peak AC), respectively. A threshold value of CNR above 6 and percentage maximum AC (peak AC) deviation range of ±20% of the reference image were considered acceptable. The proposed single-bed scan time reduction was projected to a whole-body examination (patient validation scan) using the continuous-bed-motion mode.

Results: Sphere and background ACs of 20 kBq/mL and 1 kBq/mL were selected, respectively. The optimized single-bed scan time was approximately 60 s using OSEM-TOF or OSEM-TOF+PSF (four iterations, 4.0-mm Gaussian filter and almost isotropic voxel size of 3.0-mm side length), resulting in a PET spatial resolution of 6.3 mm for OSEM-TOF and 5.5 mm for OSEM-TOF+PSF. In the patient validation, the maximum percentage difference in lesion quantification between standard and optimized protocol (whole-body scan time of 15 vs. 5 min) was below 19%.

Conclusions: A reduction of single-bed and whole-body scan time for [⁶⁸Ga]Ga-PSMA PET/CT compared to current recommended clinical acquisition protocols is postulated. Clinical studies are warranted to validate the applicability of this protocol.

Background: In endometrial cancer (EC), sentinel lymph node (SLN) mapping has emerged as an alternative to systematic lymphadenectomy. Little is known about factors that might influence SLN preoperative detection. The aim of our study was to evaluate the clinical and technical variables that may influence on the success of SLN detection in preoperative lymphatic mapping in patients with intermediate and high-risk EC when performing transvaginal ultrasound-guided myometrial injection of radiotracer (TUMIR).

Methods: Between March 2006 and March 2017, we prospectively enrolled patients with histologically confirmed EC with intermediate or high-risk of lymphatic involvement. All women underwent SLN detection by using TUMIR approach. After radiotracer injection, pelvic and abdominal planar and SPECT/CT images were acquired to obtain a preoperative lymphoscintigraphic mapping. Pattern of drainage was registered and analyzed to identify the factors directly involved in drainage. Sonographer learning curves to perform TUMIR approach were created following Cumulative Sum and Wright methods. Univariate and multivariate analyses were performed using logistic regression.

Results: During study period, 123 patients were included. SLN preoperative detection rate was 70.7%. Age under 75 years at diagnosis (P<0.01), radiotracer injection above 4 mL -high-volume- (P<0.01), and tumoral size below 2 cm (P=0.04) were associated with higher SLN preoperative detection rate. Twenty-five procedures were necessary to attain an adequate performance in TUMIR approach.

Conclusions: The higher SLN preoperative detection rate in women with intermediate and high-risk endometrial cancer after TUMIR approach was related with younger age, smaller tumors and high-volume injection of radiotracer. Sonographers are required to perform 25 procedures before acquiring an expertise in radiotracer injection.

The recent development of radionuclide therapy and radioligand therapy has raised a call for achieving the highest quality standards, for either radiopharmacy or radiation protection. Novel radionuclides are now being used, either under the form of in-house production radiopharmaceuticals or available from companies. Over the last 20 years, they include radiolabeled microspheres for selective internal radiotherapy (SIRT), the introduction of the first commercially available alpha emitter radiopharmaceutical, ²²³Ra, and the radiosynoviorthesis which is highly variable across Europe. More important is the development of radioligand therapy, often called theranostics. In this concept, a diagnostic radiopharmaceutical can determine the chance of success of a therapeutic one. Typically, diagnostic radiopharmaceuticals for positron emission tomography, are labeled with ¹⁸F or ⁶⁸Ga, such as the PSMA ligands or somatostatin analogs, and the therapeutic radiopharmaceutical is labeled with ¹⁷⁷Lu. This has revolutionized the world of Nuclear Medicine, but also all concepts that shall be applied to properly apply quality assurance and radiation protection in the field. This article will follow the example of ¹³¹I as the main used radionuclide for therapy during the last 80 years. Proposals can be general, and in parallel expert's articles will give specific guidance on issues with particular radionuclides, i.e., alpha emitters and ¹⁷⁷Lu. This article will also give insight in the radiation protection issues related to the use of microspheres radiolabeled with either ⁹⁰Y or ¹⁶⁶Ho.

Background: Extremity exposure during the handling of unsealed radioactive sources is a matter of concern for nuclear medicine workers. Next to ^99mTc and ¹⁸F, other radiopharmaceuticals have seen an increase in their use over the last decade. However, limited information on their impact on extremity dose is available. This study aimed to gain insight into the status of extremity exposure and dose monitoring in Europe.

Methods: A survey was conducted at the end of 2020 among the European Association of Nuclear Medicine community. It contained 24 questions considering department characteristics, worker tasks, dosimeter use, typical worker extremity dose, department workload for selected radionuclides (^99mTc, ¹⁸F, ⁶⁸Ga, ¹⁷⁷Lu, ⁹⁰Y) and protective measures.

Results: A total of 106 replies were received, 92% of which were from Europe. About half of the respondents were from academic hospitals. Ninety-nine departments implement extremity dose monitoring for a total of 1335 workers. Most workers (95%) wear a ring dosimeter, generally on the non-dominant hand, and 44% on the index finger. Monthly doses were generally low (median values at different ring position: 0.4-1.8 mSv), although higher doses were reported (20.8-38.8 mSv). About 1/3 of workers performed the full task range (preparation, dispensing, and administration). Administration is associated with significantly lower extremity doses. Interestingly, no correlation between department workload and collective dose was found. The adoption of vial and syringe shielding, as well as distance tools, was common. The workers dispensing ^99mTc without syringe shielding or PET nuclides without automated system received a significantly higher dose. Handling ⁶⁸Ga, ¹⁷⁷Lu and ⁹⁰Y did not appear to have an impact on the reported doses.

Conclusions: Protective measures play a significant role in lowering extremity doses, while department workload and more recently introduced radionuclides seem not to be major dose determinants.

Background: The present study evaluates the relationship between PET/CT findings and survival in patients with locally advanced cervical cancer (LACC) with a squamous cell histology.

Methods: The study included 70 patients with LACC (FIGO stage IB2-IVA). The relationship between pretreatment PET/CT parameters, age, stage, lymph node metastasis and survival was evaluated using the univariate and multivariate Cox proportional hazards model.

Results: The mean age of the 70 patients was 57.4 years and the mean duration of follow-up was 33.6 months. Disease progression occurred in 36 patients and 32 patients died during the follow-up period. In the univariate analysis, MTV-P and TLG-P were found to be related to progression-free survival (PFS), and stage, MTV-P, TLG-P and SUVmax-Ps were found to be related to overall survival (OS). However, only MTV-P and TLG-P were found to be independent prognostic factors for both PFS and OS.

Conclusions: The present findings suggest that volumetric PET parameters (MTV-P, TLG-P) predict the progression and survival of the patients with LACC.

Background: The aim of this study was to assess the long-term anti-inflammatory effect and safety of 90-Yttrium and 166-Holmium radiosynoviorthesis (RSO) for treating chronic knee synovitis of various origins.

Methods: A total of 820 patients were included in this study and were followed up to 10 years after the procedure for objective and subjective changes in signs and symptoms of inflammation.

Results: Five years after RSO, excellent and good results were seen in 71% (95% CI 67-74%) of patients. Six, seven, eight and nine years following RSO, efficacy did not decrease significantly. Ten years after RSO, the effectiveness of the therapy fell to 65% (95% CI 59-71%). Overall, 64% of patients did not need another joint puncture ten years after RSO. We achieved excellent to good results at 5 years in 79% of patients with rheumatoid arthritis, 59% with ankylosing spondylitis, and 62% with osteoarthritis. Efficacy was mainly affected by the local X-ray stage of the knee joint. A significant association was also found between the diagnosis of the underlying disease and the success of radiosynoviorthesis. Efficacy, however, was not substantially affected by any of the following factors: the duration of synovitis, the number of punctures before radiosynoviorthesis, the number of intraarticular steroid injections before the procedure, or the number of interventions before radiosynoviorthesis (radiotherapy, surgery).

Conclusions: Radiosynoviorthesis is an effective long-term method of treating chronic synovitis. The treatment showed the most favorable effects in patients with rheumatoid arthritis and those with mild to moderate degenerative osseous changes.

Chronic synovitis is contributing to the development of arthropathy in hemophilia A and B. In most patients with severe and moderate hemophilia, during lifetime, joint damage progresses despite early prophylaxis and intense treatment with coagulation factor concentrates. Recurrent hemorrhages into the joints and subclinical bleeding lead to chronic inflammation of the synovium, neoangiogenesis and remodeling, sustaining a vicious circle of bleeding-remodeling-bleeding and progression of osteochondral damage. Imaging techniques including ultrasound and MRI are able to early visualize synovitis and osteochondral changes. Early detection and sustained therapy of synovitis are important preconditions to prevent further deterioration of joint status. Chronic synovitis requires intensified substitution of coagulation factors and concomitant analgetic, antiphlogistic and physical therapy. The value of early radiosynoviorthesis (RSO) as effective method to control ongoing synovitis is discussed here. RSO is recommended as first choice therapy in case of persistant chronic synovitis, recorded in both national and international guidelines.

Background: A quantitative imaging biomarker is desirable to provide a comprehensive measure of whole-body tumor burden in patients with metastatic neuroendocrine tumors, and to standardize the evaluation of treatment-related changes. Therefore, we evaluated volumetric parameters for quantification of whole-body tumor burden from somatostatin receptor (SSR)-targeted PET/CT.

Methods: Thirty-two patients with metastastic grade1/grade 2 gastroenteropancreatic neuroendocrine tumors who underwent a ⁶⁸Ga-DOTA-TATE PET/CT for staging of disease before initiation of peptide receptor radionuclide therapy were included in this retrospective cohort analysis. Volumetric parameters of tumor lesions, SSR-derived tumor volume (SSR-TV) and total lesion SSR (TL-SSR), were calculated for each patient using a computerized volumetric technique with a 40% SUVmax cut-off, and compared with serum chromogranin A (CgA) levels. Progression-free survival (PFS) was determined in relation to volumetric parameters. In a subgroup of 18 patients, the feasibility of volumetric parameters for treatment monitoring was evaluated.

Results: Mean SSR-TV was 178±214 cm³ (range, 9-797 cm³), whereas mean TL-SSR was 4096±5191 cm³ (range, 61-19,203 cm³). Baseline CgA levels were associated with whole-body tumor burden (SSR-TV, r=0.57, P=0.0008; and TL-SSR, r=0.43, P=0.01, respectively). PFS was shorter in patients with high SSR-TV and high TL-SSR (HR 5.16, 95% CI, 1.61-29.67), P=0.009), and SSR-TV (P=0.0067) and TL-SSR (P=0.0215) emerged as the sole predictors of progression in regression analysis. Changes in CgA did not correctly identify treatment response (P=0.25).

Conclusions: SSR-derived volumetric parameters provide a quantitative imaging biomarker for whole-body tumor burden, and may hold potential as a clear-cut measure for assessment of treatment response.

Arthritis is affecting millions of people globally, involvement and distribution depending on the type of arthritis. The most common arthritic conditions are osteoarthritis (OA) and rheumatoid arthritis (RA). Despite the pathogeneses being fundamentally different, both joint diseases share the same need for local treatment of synovitis. No current treatment can stop the progression of OA. Local articulate treatment including glucocorticoid (GC) injections, radiosynoviorthesis (RSO) and surgical synovectomy are the only options to relieve pain and temporally improve movability before surgical intervention. For RA, despite effective systemic treatments, similarly need for local articulate treatment is still present, especially early in the disease, but also in case of recurrent episodes of disease flare. Current evidence supports local GC injection as first line treatment for persistent synovitis in a single or a few joints. RSO provides an evident and effective alternative for GC refractory synovitis, especially in early RA. Surgical synovectomy is an invasive alternative, but with less documented efficacy. Whether one unsuccessful intraarticular GC injection is enough to change of mode of action for local treatment is still unclear and needs to be further investigated. In conclusion persistent single joint synovitis in OA and RA is well treated with local treatment. Intra-articular GC injection is considered as first line of treatment, but RSO provides an additional treatment alternative with less side effects and better evidence of efficacy than surgical synovectomy.