The lung shunt fraction (LSF) is estimated using Tc-macroaggregated albumin (Tc-MAA) imaging before selective internal radiotherapy (SIRT) of the liver to reduce the risk of pulmonary irradiation. Generally, planar scans are acquired after injection of Tc-MAA into the hepatic artery. However, the validity of this approach is limited by differences in attenuation between liver and lung tissue as well as inaccurate segmentation of the organs. The aim of this study was to evaluate quantitative SPECT/CT for LSF assessment in a prospective clinical cohort. Fifty consecutive patients intended to undergo SIRT were imaged within 1 h after injection of Tc-MAA using a SPECT/CT γ-camera. Planar scans of the lung and liver region were acquired in anterior and posterior views, followed by SPECT/CT scans of the thorax and abdomen. Emission data were corrected for scatter, attenuation, and resolution recovery using dedicated software. To quantify the radioactivity concentration in the lung, liver, urinary bladder and remainder of the thoracoabdominal body, volumes of interest were defined on the SPECT/CT images.Tc-MAA concentrations were calculated as percentage injected dose (%ID). MeanTc-MAA uptake in liver and lung accounted for only 79 %ID, whereas 13.1 %ID was present in the remainder of the body. In all patients, LSF as calculated from planar scans accounted for a median of 6.8% (range, 3.4%-32.3%), whereas the SPECT/CT quantitation revealed significantly lower LSF estimates, at a median of 1.9% (range, 0.8%-15.7%) ( < 0.0001, Wilcoxon test). On the basis of planar imaging, dose reduction or even contraindications to SIRT had to be considered in 10 of 50 patients, as their LSF was calculated at 10% or more. In contrast, SPECT/CT quantitation showed substantial shunting in only 2 of the 50 patients. Quantitative SPECT/CT reveals that the LSF is considerably lower than shown on planar imaging. Thus, the resulting dose to the lung parenchyma may be less than conventionally assumed. However, the safety of the SPECT/CT-derived dose range will have to be evaluated.

In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery. The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 microg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 microg/l (0.25 to 2.3) and the cobalt level was 0.4 microg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 microg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 microg/l (0.25 to 3.9) whereas the cobalt level was 1.4 microg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001). Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

Lymph node metastases (LNM) are present in a minority of patients with early stages of cervical carcinomas. As conventional imaging including PET/CT has shown limited sensitivity, systematic lymphadenectomies are often conducted for staging purposes.Therefore, the aim of this prospective study was to analyze the impact of 18 F-FDG PET/MRI in addition to sentinel node (SLN) biopsy on lymph node status. Methods: 42 women with initial diagnosis of FIGO IA-IIB cervical carcinomas were included between 03/2016-04/2019. Each patient received preoperative whole body 18 F-FDG PET/MRI (Biograph mMR®, Siemens Healthineers) and SLN imaging with SPECT/CT (Discovery 670 Pro®, GE Healthcare) after intracervical injection of 99m Tc-labeled nanocolloid. Systematic Lymphadenectomy and SLN biopsy served as reference standard. Staging in PET/MRI was performed as a consensus of nuclear medicine and radiology experts. Results: One patient was excluded from surgical staging due to newly diagnosed liver metastases in PET/MRI. Overall prevalence of LNM in the remaining 41 patients was 29.3% (12/41). 5/12 patients with LNM solely had small metastases with maximum diameter ≤5mm. Interpretation of PET/MRI as a consensus of experts showed a specificity of 100% (29/29, 95%CI: 88.3-100%) for LNM-staging, but a low sensitivity of 33.3% (4/12, 95%CI: 12.8-60.9%). LN size was the most important factor for the detectability of metastases, since only LNM >5mm could be identified by PET/MRI (sensitivity >5mm: 57.1%; ≤5mm: 0%). Paraaortic LNM were evaluated accurately in 3/4 cases (16 patients with paraaortic LN removal). SLNs were detectable by SPECT/CT in 82.9% of the patients or 69.0% of hemipelvis. In cases with undetectable SLN in SPEC/TCT, malignancy rate was considerably higher (31.2% vs.19.3%). The combination of PET/MRI and SLN SPECT/CT improved the detection of pelvic LNM from 33.3% to 75%. Conclusion: 18 F-FDG PET/MRI is a highly specific Nstaging method and improves LNM detection. Due to the limited sensitivity in frequently occurring small LNM, PET/MRI should be combined with sentinel node mapping. The proposed combined protocol helps to decide whether extensive surgical staging is necessary in patients with FIGO I/II cervical cancer.

Rationale Radium-223-Dichloride (Ra-223) is an alpha-emitter, used to treat bone metastases. Patients with high metastatic burden and/or with increased trabecular bone uptake could present a higher incidence of hematologic toxicity. We hypothesized that these two factors are predictors of bone marrow failure. Material and Methods A computer algorithm discriminated between trabecular bone (BVol) and tumor metastases (MVol) within pretherapeutic whole-body skeletal SPECT/CT (N = 47). The program calculated the metastatic invasion percent (INV%) as the MVol/(MVol + BVol) ratio and extracted the BVol mean counts. BVol counts were correlated to % drop of hemoglobin (Hb), leukocytes (WBC), and platelets (PLT) after 3/6 Ra-223 cycles. Patient-specific and computational-derived parameters were tested as predictors of hematologic toxicity with MANOVA. Results B Vol counts correlated with drop of Hb (R = 0,65, p < 0.01) and PLT (R = 0,45, p < 0.01). Appendicular BVol counts showed a better correlation (p < 0.05, p < 0.01, and p < 0.001 for Hb, WBC, and PLT, resp.). INV% directly correlated with BVol counts (R = 0.68, p < 0.001). At MANOVA, grade III/IV toxicity was predicted by INV% (p < 0.01), by long-bone invasion (p < 0.005), and by BVol counts (p < 0.05). Conclusions In patients with significant bone tumor burden, degree of bone invasion and trabecular bone uptake are predictors of subsequent bone marrow failure.

Rationale Radiolabelled bisphosphonates such as 99mTc-DPD typically show intense uptake in skeletal metastases from metastatic castration resistant prostate cancer (mCRPC). Extensive bone involvement is regarded a risk factor for mCRPC patients treated with 223Ra-radiumdichloride (223Ra). Aim of this study was to quantify 99mTc-DPD uptake by means of SPECT/CT prior to 223Ra and compare results to the feasibility of treatment and overall survival (OS). Methods 60 consecutive mCRPC patients were prospectively included into this study. SPECT/CTs of the central skeleton covering the scull to mid-femoral level were carried out before the first cycle of 223Ra. The bone compartment was defined by means of low-dose CT. Emission data were corrected for scatter, attenuation and decay supplemented by resolution recovery using dedicated software. The Kaplan-Meier estimator, U-Test and Cox regression analysis were employed for statistics. Results Total 99mTc-DPD uptake of the central skeleton varied between 11-56 percent of injected dose (%ID) or 1.8-10.5 %ID/1000 ml bone volume (%ID/L). SUVmean ranged from 1.9-7.4 while SUVmax range was 18-248. Patients unable to complete 223Ra treatment due to progression a/o. cytopenia (n=23) showed significantly higher uptake (31.9 vs. 25.4%ID; 6.0 vs 4.7x %ID/L, P <0.02). OS after 223Ra (median: 15.2 months) was reduced to 7.3 months in case of skeletal uptake ≥26 %ID as compared to 30.8 months if <26 %ID (p=0.008). Similar results were obtained for %ID/L and SUVmean. SUVmax was not correlated to survival. %ID/L was identified as an independent prognostic factor for OS (Hazard ratio 1.381 per unit) along with number of previous treatment lines. Conclusion Quantitative SPECT/CT of bone scans performed at baseline is prognostic for survival of mCRPC patients treated with 223Ra.