[en] Ra-dichloride is an alpha-emitting radiopharmaceutical used in the treatment of bone metastases from castration-resistant prostate cancer. Image-based dosimetric studies remain challenging because the emitted photons are few. The aim of this study was to implement a methodology for in-vivo quantitative planar imaging, and to assess the absorbed dose to lesions using the MIRD approach. The study included nine Caucasian patients with 24 lesions (6 humeral head lesions, 4 iliac wing lesions, 2 scapular lesions, 5 trochanter lesions, 3 vertebral lesions, 3 glenoid lesions, 1 coxofemoral lesion). The treatment consisted of six injections (one every 4 weeks) of 50 kBq per kg body weight. Gamma-camera calibrations for "2"2"3Ra included measurements of sensitivity and transmission curves. Patients were statically imaged for 30 min, using an MEGP collimator, double-peak acquisition, and filtering to improve the image quality. Lesions were delineated on "9"9"mTc-MDP whole-body images, and the ROIs superimposed on the "2"2"3Ra images after image coregistration. The activity was quantified with background, attenuation, and scatter correction. Absorbed doses were assessed deriving the S values from the S factors for soft-tissue spheres of OLINDA/EXM, evaluating the lesion volumes by delineation on the CT images. In 12 lesions with a wash-in phase the biokinetics were assumed to be biexponential, and to be monoexponential in the remainder. The optimal timing for serial acquisitions was between 1 and 5 h, between 18 and 24 h, between 48 and 60 h, and between 7 and 15 days. The error in cumulated activity neglecting the wash-in phase was between 2 % and 12 %. The mean effective half-life (T_1_/_2_e_f_f) of "2"2"3Ra was 8.2 days (range 5.5-11.4 days). The absorbed dose (D) after the first injection was 0.7 Gy (range 0.2-1.9 Gy). Considering the relative biological effectiveness (RBE) of alpha particles (RBE = 5), D_R_B_E = 899 mGy/MBq (range 340-2,450 mGy/MBq). The percent uptake of "9"9"mTc and "2"2"3Ra (activity extrapolated to t = 0) were significantly correlated. The feasibility of in vivo quantitative imaging in "2"2"3Ra therapy was confirmed. The lesion uptake of "2"2"3Ra-dichloride was significantly correlated with that of "9"9"mTc-MDP. The D_R_B_E to lesions per unit administered activity was much higher than that of other bone-seeking radiopharmaceuticals, but considering a standard administration of 21 MBq (six injections of 50 kBq/kg to a 70-kg patient), the mean cumulative value of D_R_B_E was about 19 Gy, and was therefore in the range of those of other radiopharmaceuticals. The macrodosimetry of bone metastases in treatments with "2"2"3Ra-dichloride is feasible, but more work is needed to demonstrate its helpfulness in predicting clinical outcomes. (orig.)

[en] We studied removal of radioactive cesium from Wakasagi collected in Kasumigaura Shore. The radioactivity of cesium in Wakasagi exists in he muscle mainly. The radioactivity of cesium in Wakasagi of Kasumigaura Shore is currently decreasing to the density to about 40 Bq/kg, and it was able to decrease to the level of 6.6 - 20.4 Bq/kg by extracting with the water. (author)

No abstract available

[en] The seasonal variation of the "7Be activities in air was monitored by a continuous sampling with a high volume air dust sampler. And also, "7Be and "3H activities in precipitation were determined. The activity level of "7Be in air was ranged from 1.94 to 47.2 Bq/m"3. And "7Be in the precipitation was separated using cation exchange resin and the monthly average activity level was ranged from 0.29 to 4.77 Bq/L. "3H was analyzed using electrolytic enrichment method and activity ranged from 0.27 to 2.22 Bq/L. (author)

[en] It is necessary to develop the rapid and on-site detection method of radiocesium (Cs) in soil in order to carry out the decontamination of radioactive materials efficiently. The most common analyzer for the quantitative analysis of radio-Cs is the gamma ray spectrometer with the semiconductor Germanium (Ge) detector to evaluate the concentrations of radio-Cs in soil. However, this equipment is large-size, and demand liquid nitrogen cooling. So it is not suitable for on-site measurements. Here we show that there is a highly significant correlation between the analytical values of the portable NaI(Tl) spectrometer and that of the Ge spectrometer. This indicates that the portable spectrometer enable us to determine the quantity of the concentration of radio-Cs in soil on site. Then, we also measured the contaminant soil by three kind of handy survey meters (NaI(Tl) detector, GM, and CsI(Tl) detector) under the fixed condition. These measurement values have good correlations with the concentration of radio-Cs. It is suggested that the radio-Cs concentrations are estimated by the handy instruments under the controlled measurement condition. (author)

[en] A nuclear power plant accident, which occurred on March 11, 2011, caused severe radioactive contamination in Fukushima. We initiated an environmental radioactive survey in Minami-Soma City the following October. The city is located approximately 10-40 km north of the TEPCO's Fukushima Daiichi Nuclear Power Plant. The study reported here involves an environmental radioactive survey conducted along three rivers and their tributary streams. Water and bottom sands were collected from four to six sampling locations along each river. Water samples (1 L) were dried on thin Teflon sheets, and gamma-ray measurements were performed with a well-type Ge detector. Sand samples were homogenized after drying, and approximately 50 g were measured for gamma-rays with a low-background coaxial-type Ge detector. The Cs concentrations ("1"3"7Cs+"1"3"4Cs) were determined to be 10,000-20,000 Bq/kg in the bottom sand collected from the upper reaches of the rivers, whereas the concentrations measured from samples collected near coastal down reaches were measured at about 200 Bq/kg. The Cs concentrations measured in river water were about 0.8 Bq/L in the upper reaches of the rivers and 0.3 Bq/L in the lower reaches, indicating that the Cs concentration in water is quite low. It is necessary to study the behavior of the contaminants in the upper reaches of the river system, and determine if they will move to the down stream area hereafter. (author)

[en] Treatment with ¹³¹I-MIBG is associated with significant thyroid damage. This study was undertaken to investigate the long-term efficacy of current thyroid prophylaxis, to explore the relationship between thyroid dysfunction and thyroid volume after exposure to ¹³¹I-MIBG and to evaluate the possible negative effects of ¹³¹I^- on the parathyroid glands. Of 81 long-term surviving patients with neuroblastoma treated with ¹³¹I-MIBG during the period 1999-2012, 24 were finally evaluated. Patients received thyroxine (T4), methimazole and potassium iodide as thyroid protection. In all patients (para)thyroid function was evaluated and ultrasound investigation of the (para)thyroid gland(s) was performed. Thyroid dysfunction was defined as a plasma thyrotropin concentration >5.0 mU/L (thyrotropin elevation, TE) or as the use of T4 at the time of follow-up. Hyperparathyroidism was defined as a serum calcium concentration above the age-related reference range in combination with an inappropriately high parathyroid hormone level. At a median follow-up of 9.0 years after ¹³¹I-MIBG treatment, thyroid disorders were seen in 12 patients (50 %; 9 with TE, 5 with a thyroid nodule and 1 patient was subsequently diagnosed with differentiated thyroid carcinoma). No significant risk factors for the occurrence of thyroid damage could be identified. In 14 of 21 patients (67 %) in whom thyroid volume could be determined, the volume was considered small (<-2SD) for age and gender. Patients treated with T4 at the time of follow-up had significantly smaller thyroid volumes for age than patients without T4 treatment (p = 0.014). None of the patients was diagnosed with hyperparathyroidism. Thyroid protection during treatment with ¹³¹I-MIBG needs attention and must be further improved, as thyroid disorders are still frequently seen despite current thyroid prophylaxis. Reduced thyroid volume in neuroblastoma survivors may be related to previous ¹³¹I-MIBG therapy or current T4 treatment. No deleterious effects of ¹³¹I-MIBG on the parathyroid glands could be found. (orig.)

[en] In the diagnosis of head and neck melanoma, lymphatic drainage is complex and highly variable. As regional lymph node metastasis is one of the most important prognostic factors, lymphoscintigraphy can help map individual drainage patterns. The aim of this study was to compare the results of lymphoscintigraphy and sentinel lymph node (SLN) detection with theoretical anatomical patterns of lymphatic drainage based on the location of the primary tumour lesion in patients with head and neck melanoma. We also determined the percentage of discrepancies between our lymphoscintigraphy and the theoretical location of nodal drainage predicted by a large lymphoscintigraphic database, in order to explain recurrence and false-negative SLN biopsies. In this retrospective study of 152 patients with head and neck melanoma, the locations of the SLNs on lymphoscintigraphy and detected intraoperatively were compared with the lymphatic drainage predicted by on-line software based on a large melanoma database. All patients showed lymphatic drainage and in all patients at least one SLN was identified by lymphoscintigraphy. Of the 152 patients, 4 had a primary lesion in areas that were not described in the Sydney Melanoma Unit database, so agreement could only be evaluated in 148 patients. Agreement between lymphoscintigraphic findings and the theoretical lymphatic drainage predicted by the software was completely concordant in 119 of the 148 patients (80.4 %, 95 % CI 73.3 - 86 %). However, this concordance was partial (some concordant nodes and others not) in 18 patients (12.2 %, 95 % CI 7.8 - 18.4 %). Discordance was complete in 11 patients (7.4 %, 95 % CI 4.2 - 12.8 %). In melanoma of the head and neck there is a high correlation between lymphatic drainage found by lymphoscintigraphy and the predicted drainage pattern and basins provided by a large reference database. Due to unpredictable drainage, preoperative lymphoscintigraphy is essential to accurately detect the SLNs in head and neck melanoma. (orig.)

[en] Performing micturiting cystourethrography (MCUG) in young children with recurrent urinary tract infections is controversial with discrepancy among the major guidelines. Previous studies have shown that a normal dimercaptosuccinic acid (DMSA) scintigraphy may avoid the need of performing MCUG for detecting vesicoureteric reflux in children with first febrile urinary tract infection. However, the role of DMSA for ruling out vesicoureteric reflux in children with recurrent urinary tract infections has not been studied. Approval from institutional ethical review committee was sought and the requirement of informed consent was waived. A total of 50 children under the age of 10 years with recurrent urinary tract infections underwent MCUG scan within 3 months of DMSA scan from January 2011 to September 2012 at our institution. Diagnosis of recurrent urinary tract infections and grading of vesicoureteric reflux was according to previously established standards. Abnormalities on DMSA scan - scarring, hydronephrosis and reduced differential renal function - were compared with presence of vesicoureteric reflux on MCUG. High-grade vesicoureteric reflux was noted on MCUG in 22 (44%) cases. The findings on DMSA included hydronephrosis and scarring in 25 (50%) and 25 (50%) cases, respectively. Abnormalities on DMSA scan for detecting the presence of high-grade vesicoureteric reflux on MCUG examination had sensitivity, specificity, positive and negative predictive values of 95.45%, 35.71%, 53.85% and 90.91%, respectively. The positive and negative likelihood ratios were 1.48 and 0.13 respectively. DMSA scan had high overall sensitivity and negative predictive value with a low negative likelihood ratio for ruling out high-grade vesicoureteric reflux on MCUG, which may obviate the need of invasive MCUG along with its associated drawbacks. (orig.)

[en] Recent advancements in PET technology have brought with it significant improvements in PET performance and image quality. In particular, the extension of the axial field of view of PET systems, and the introduction of semiconductor technology into the PET detector, initially for PET/MR, and more recently available long-field-of-view PET/CT systems (≥ 25 cm) have brought a step change improvement in the sensitivity of PET scanners. Given the requirement to limit paediatric doses, this increase in sensitivity is extremely welcome for the imaging of children and young people. This is even more relevant with PET/MR, where the lack of CT exposures brings further dose reduction benefits to this population. In this short article, we give some details around the benefits around new PET technology including PET/MR and its implications on the EANM paediatric dosage card. Reflecting on EANM adult guidance on injected activities, and making reference to bed overlap and the concept of MBq.min bed${}^{-<!--\; ???\; -->1}$ kg${}^{-<!--\; ???\; -->1}$, we use published data on image quality from PET/MR systems to update the paediatric dosage card for PET/MR and extended axial field of view (≥ 25 cm) PET/CT systems. However, this communication does not cover the expansion of paediatric dosing for the half-body and total-body scanners that have recently come to market. In analogy to the existing EANM dosage card, new parameters for the EANM paediatric dosage card were developed (class B, baseline value: 10.7 MBq, minimum recommended activity 10 MBq). The recommended administered activities for the systems considered in this communication range from 11 MBq [${}^{18}$F]FDG for a child with a weight of 3 kg to 149 MBq [${}^{18}$F]FDG for a paediatric patient weight of 68 kg, assuming a scan of 3 min per bed position. The mean effective dose over all ages (1 year and older) is 2.85 mSv. With this, recommendations for paediatric dosing are given for systems that have not been considered previously.