Dosimetry during iodine-131 therapy - a technical point of view from a single centre's own experience.

BACKGROUND: Nuclear medicine uses radionuclides in medicine for diagnosis, staging, therapy, and monitoring the response to therapy. The application of radiopharmaceutical therapy for the treatment of certain diseases is well-established, and the field is expanding. Internal dosimetry is multifaceted and includes different workflows, as well as various calculations based on patient- specific dosimetry. AIM: The objective of this study was to introduce the technical issues which might occur during iodine-131 (¹³¹I) dosimetry performed in nuclear medicine departments. MATERIAL AND METHODS: Retrospective analysis was performed on a group of 44 patients with papillary thyroid cancer who between May 2021 and October 2021 underwent a 131I treatment: 80-100 mCi (2200-3700 MBq, based on the previous medical history and stage of the disease). Patients underwent a series of ¹³¹I therapy scans using gamma camera Discovery NM 670 CT. Whole body scan (WBS) was performed 2, 4, 24 and 48 hours after ¹³¹I administration. Additionally, after 24 hours of single photon emission computed tomography/ computed tomography, two fields of view (SPECT/CT 2-FOV) were performed from the mid-head to the bladder. RESULTS: During the dosimetry procedure, several issues arise. Firstly, after receiving therapeutic doses of ¹³¹I, patients should remain in their rooms until the appropriate activity is achieved before being transported to the diagnostic room. Secondly, the walls between examination rooms meet the requirements for accurate diagnosis but not for therapy, leading to the occurrence of artefacts in patients examined behind the wall, potentially influencing the examination results. Thirdly, personnel in the control room also experience additional exposure (10 times greater than in the case of standard diagnostic procedure). CONCLUSIONS: The dosimetry in patients in whom therapeutic procedures are performed with the use of isotopes is mandatory according to Polish and European law, technical issues which occur during the dosimetry procedures might influence the organization of the work in departments.

Metabolic syndrome as risk factor for left ventricular hypertrophy in children with chronic kidney disease.

Background: The metabolic syndrome (MS), a cluster of clinical and biochemical abnormalities including insulin resistance, dyslipidemia and hypertension, is often diagnosed in chronic kidney disease (CKD) children. Left ventricular hypertrophy (LVH) is a major target organ damage in hypertension and an important cardiovascular risk factor in CKD patients. We aimed to identify the most significant risk factors of LVH in children with CKD. Methods: Children with CKD stage 1-5 were enrolled in the study. MS was diagnosed according to De Ferranti (DF) as ≥3 from 5 criteria. Ambulatory blood pressure measurements (ABPM) and echocardiographic evaluation were performed. LVH was defined as ≥95th percentile of LV mass index related to height and age. Clinical and laboratory parameters included: serum albumin, Ca, HCT, cystatin C, creatinine, estimated glomerular filtration rate (eGFR) based on Schwartz formula, triglycerides, high-density lipoprotein (HDL), proteinuria, BMI standard deviation score (SDS), height SDS, waist circumference, ABPM data. Results: 71 children (28 girls/43 boys) with median age 14.05 (25%-75%:10.03-16.30) years and median eGFR 66.75 (32.76-92.32) ml/min/1.73m2 were evaluated. CKD stage 5 was diagnosed in 11 pts (15.5%). MS (DF) was diagnosed in 20 pts (28.2%). Glucose ≥ 110 mg/dL was present in 3 pts (4.2%); waist circumference ≥75th pc in 16 pts (22.5%); triglycerides ≥ 100 mg/dL in 35 pts (49.3%); HDL < 50mg/dL in 31 pts (43.7%) and BP ≥ 90th pc in 29 pts (40.8%), respectively. LVH was detected in 21 (29.6%) children. In univariate regression the strongest risk factor for LVH was CKD stage 5 (OR 4.9, p=0.0019) and low height SDS (OR 0.43,p=0.0009). In stepwise multiple logistic regression analysis (logit model) of the most important risk factors for LVH in CKD children, only three were statistically significant predictors: 1)MS diagnosis based on DF criteria (OR=24.11; 95%CI 1.1-528.7; p=0.043; Chi2 = 8.38,p=0.0038); 2), high mean arterial pressure (MAP SDS) in ABPM (OR=2.812; 95%CI 1.057-7.48; p=0.038;Chi2 = 5.91, p=0.015) and 3) low height SDS (OR=0.078; 95%CI 0.013-0.486;p=0.006; Chi2 = 25.01, p<0.001). Conclusions: In children with chronic kidney disease LVH is associated with the cluster of multiple factors, among them the components of MS, hypertension, stage 5 CKD and growth deficit were the most significant.

Modification of the Schwartz equations for children increases their accuracy at eGFR > 60 mL/min/1.73 m(2).

AIM: Estimation of eGFR in children with normal kidney function using the Schwartz equations results in underestimating real GFR. MATERIALS AND METHODS: We propose modification of three Schwartz equations - two based on creatinine concentration (eGFRScrBS bedside) and (eGFRScr) and one 3-marker based on creatinine, urea and cystatin C concentrations (eGFRS3M). The iohexol test (reference method) was performed 417 times in 353 children >2 years with mean GFR: 98 ± 31.6 ml/min/1.73m(2). The assessment included also the Filler and Zappitelli equations. The modification was performed using methods: (1) based on equation, eGFRcor = a [eGFR - T] + T, where T = 50, if eGFR > T, and a equals for: eGFRScrBS 1.4043, for eGFRScr 2.0048, for eGFRS3M 1.2951, and (2) based on correction of all coefficients of the original equation. RESULTS: For comparison of all the results and for children with GFR< 60, 60-90, 90-135 and > 135 ml/min/1.73m(2) the correlation coefficient, relative error (RE) and root mean square relative error (RMSRE) was employed and revealed improvement of RE from 25.9 to 6.8 and 3.9% (depending on the correction method) for eGFRScr; from 19 to 8.1 and 3.9% for eGFRScrBS and: from 11.6% to 2.0 and 2.3% for eGFRS3M (respectively). The RMSRE values changed from 30 to 21.3 and 19.8% for eGFRScr, from 25.1 to 21.6 and 19.8% for eGFRScrBS and from 19.1 to 15.8 and 15.3 % for eGFRS3M. CONCLUSIONS: Modifications of Schwartz equations at GFR > 60 ml/min/1.73m(2) significantly improves the accuracy of calculating eGFR. The 3-markers equation is more accurate and should be employed frequently.

Which equations should and which should not be employed in calculating eGFR in children?

PURPOSE: We assessed the reliability of calculating eGFR in children as compared to the iohexol disappearance test (GFR-I), which was performed 417 times in 353 children aged 2 and more. MATERIAL/METHODS: eGFR was estimated with equations based on serum creatinine: Schwartz (1: eGFR-Scr), Cockroft-Gault (2: eGFR-CG) and MDRD (3: eGFR-MDRD), and on creatinine clearance (4: eGFR-U), or relying on serum cystatin C: Hoeck (5: eGFR-H), Bokenkamp (6: eGFR-B) and Filler (7: eGFR-F), and on the three Schwartz markers (8: eGFR-S3M). Mean relative error (RE), correlation (R), Bland-Altman analysis and accuracy of GFR-I were studied in all patients and in subgroups: at GFR<60ml/min/1.73m(2); in children aged ≤12 and >12. RESULTS: The results by eGFR-Scr, eGFR-S3M demonstrated no statistical difference to GFR-I at GFR<60ml/min/1.73m(2), but underestimated eGFR at higher filtration values by 11.6±15.1% and 19.1±16.4, respectively (p<0.0000). The eGFR-B, eGFR-F and eGFR-MDRD equations illustrated important overestimation of reference GFR results (RE: 84±44.2%; 29.5±27.9%, 35.6±62%; p<0.0000 for all). The MDRD and C-G formulas showed statistically better consistency in children aged >12. A good agreement was achieved by the eGFR-H equation (5.1±21.9%; p<0.0000; R=0.78). CONCLUSIONS: (1) Schwartz equations show a good conformity at GFR<60ml/min/1.73m(2), but underestimate the results at higher GFR values. (2) The Bokenkamp equation with original coefficient should not be employed in children. (3) The use of the Hoeck formula in all children and C-G and MDRD formula in children aged >12 is possible. (4) The error of eGFR calculations increases at higher GFR values.

Genotype-phenotype associations in WT1 glomerulopathy.

WT1 mutations cause a wide spectrum of renal and extrarenal manifestations. Here we evaluated disease prevalence, phenotype spectrum, and genotype-phenotype correlations of 61 patients with WT1-related steroid-resistant nephrotic syndrome relative to 700 WT1-negative patients, all with steroid-resistant nephrotic syndrome. WT1 patients more frequently presented with chronic kidney disease and hypertension at diagnosis and exhibited more rapid disease progression. Focal segmental glomerulosclerosis was equally prevalent in both cohorts, but diffuse mesangial sclerosis was largely specific for WT1 disease and was present in 34% of cases. Sex reversal and/or urogenital abnormalities (52%), Wilms tumor (38%), and gonadoblastoma (5%) were almost exclusive to WT1 disease. Missense substitutions affecting DNA-binding residues were associated with diffuse mesangial sclerosis (74%), early steroid-resistant nephrotic syndrome onset, and rapid progression to ESRD. Truncating mutations conferred the highest Wilms tumor risk (78%) but typically late-onset steroid-resistant nephrotic syndrome. Intronic (KTS) mutations were most likely to present as isolated steroid-resistant nephrotic syndrome (37%) with a median onset at an age of 4.5 years, focal segmental glomerulosclerosis on biopsy, and slow progression (median ESRD age 13.6 years). Thus, there is a wide range of expressivity, solid genotype-phenotype associations, and a high risk and significance of extrarenal complications in WT1-associated nephropathy. We suggest that all children with steroid-resistant nephrotic syndrome undergo WT1 gene screening.

Serum interleukin 6 levels as an early marker of acute kidney injury on children after cardiac surgery.

BACKGROUND: Cardiosurgical operations in cardiopulmonary bypass (CPB) constitute a risk of acute kidney injury (AKI). OBJECTIVES: The aim of the study was an assessment of AKI risk in children within the first 24 hours after CPB cardiac surgery, evaluating serum interleukin 6 (sIL6). MATERIAL AND METHODS: The study included 47 children with congenital heart disease operated in CPB. Blood samples were taken before the procedure (0 hour) as well as at 2, 6, 12, 18 and 24 hours after the operation. RESULTS: AKI was confirmed in 19 children. The mean sIL6 concentration in the AKI compared with non-AKI group was: 180.6 vs. 93.7; p = 0.0017. The maximum sIL6 in the AKI group was obtained at 2 hrs after CPB (350.36 pg/ml). Logistic regression analysis for AKI development depending on the value of sIL6 at 2 hrs after CPB proved that every rise of sIL6 by 100 pg/ml increased the chance of AKI development by 70% (p = 0.0161). With every circulatory arrest time prolongation by 10 minutes for a given sIL6 concentration, the chance of AKI development increased by 47% (p = 0.0407). AKI risk at 2 hrs after CPB, for a sIL6 cut-off point amounting to 185 pg/ml, increased more than 3-fold (AUROC - 68%). CONCLUSIONS: Determining sIL6 in children after cardiosurgical operations at 2 hrs after the procedure constitutes a good, yet not a perfect marker of AKI risk development. Nomograms of the constant risk values of AKI were worked out presenting the ranges of values in relation to serum IL6 concentrations and the child's body mass, age and the time of circulatory arrest.

[Mycophenolate mofetil in treatment of childhood nephrotic syndrome--preliminary report]. / Mykofenolan mofetilu w leczeniu dzieci z zespolem nerczycowym--doniesienie wstepne.

The management of nephrotic syndrome (NS) in children remains a clinical challenge for pediatricians and pediatric nephrologists. Especially, the treatment of patients with steroid-resistant (SR) and steroid-dependent (SD) nephrotic syndrome, because they are at risk for developing complications from prolonged exposure to steroids, CsA and alkylating agents. Mycophenolate mofetil (MMF) is a selective and reversible inhibitor of inosine monophosphate dehydrogenase used above all in transplantology and recently also in patients with nephrotic syndrome. The aim of this study was to tentatively assess the usefulness and the safety of MMF as an immunosuppressive agent in children with steroid-resistant NS, in whom remission was not obtained with previous treatment regimens, and those with steroid-dependent NS, in whom severe adverse reactions were observed in steroid and cyclosporine therapy. The study included 19 children with NS (11 girls, 8 boys) aged 7 to 19.5 years (a mean of 13.5), treated at the Deptartment of Pediatric Nephrology. The duration of disease was from 1 to 16 years (a mean of 9.3). The patients were divided into 3 groups: I--9 children with steroid-dependent NS; II--6 children with steroid-dependent NS and episodes of steroid-resistance; III--4 children with steroid-resistant NS. All patients in groups II and III required multi-drug therapy (prednisone, cyclosporine A, methylprednisolone, chlorambucil, cyclophosphamide) before MMF was introduced. MMF was administered orally: 180-600 mg/m2 body surface/dose, twice daily. The follow-up period lasted for 4 to 16 months (a mean of 7.7). The clinical outcome analysis included decrease or disappearance of proteinuria, clinical improvement and/or possibility of tapering therapy intensity, especially the dosage of steroids and/or CsA. Also, renal function was monitored with serum cystatine C concentration. Particular attention was paid to adverse effects of MMF upon the gastro- intestinal tract and/or opportunistic infections. All medication (apart from MMF) could be discontinued in 4 patients; in 15 cases, prednizone dose was reduced and in 9 cases CsA dose was reduced or discontinued. In group I (SD) steroid treatment could be reduced from a mean prednisone dose of 22.8 to 3.6 mg/m2/48 hours (p=0.018), in groups II and III, in spite of 50 % reduction of a mean prednisone dose, the difference did not reach statistical significance. During MMF therapy Csa treatment could be reduced from a mean CsA dose 4.3 to 2.9 mg/kg/24 hours (p=0.008). Improvement or preservation of stable renal function was observed in all patients--cystatin C levels decreased significantly from a mean 1.35 to 0.96 mg/l (p=0.007). Adverse reaction to MMF (abdominal pain) was observed in 2 patients (nausea, vomiting, diarrhoea in 1, CMV infection in 1). The initial clinical observation of MMF treatment in nephrotic patients shows its best effect in the group of patients with steroid-dependent NS. MMF can safely be used in children with NS. The introduction of MMF allows for reduction of other chronically used medications, especially CsA and steroids.