Intra-individual comparison of prostate-specific membrane antigen positron emission tomography/computed tomography versus bone scan in detecting skeletal metastasis at prostate cancer diagnosis.

OBJECTIVES: To compare the diagnostic performance and radiological staging impact of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) compared to 99 Tc whole-body bone scan (WBBS) for the detection of skeletal metastasis in the primary staging of prostate cancer (PCa). PATIENTS AND METHODS: A prospective institutional database was retrospectively examined for patients who underwent both PSMA PET and WBBS within a 1 week interval for PCa primary staging. Lesions were categorised as 'negative', 'equivocal', or 'definite' based on nuclear medicine physician interpretation. Metastatic burden was characterised for each imaging modality according to three groups: (i) local disease (no skeletal metastases), (ii) oligometastatic disease (three or fewer skeletal metastases), or (iii) polymetastatic disease (more than three skeletal metastases). RESULTS: There were 667 patients included. The median (interquartile range) prostate-specific antigen level was 9.2 (6.2-16) ng/mL and 60% of patients were high risk according to a modified D'Amico risk classification. The overall distribution of skeletal metastasis detection changed across the two scans overall (P = 0.003), being maintained within high-risk (P = 0.030) and low-risk (P = 0.018) groups. PSMA PET/CT identified more definite skeletal metastases compared to WBBS overall (10.3% vs 7.3%), and according to risk grouping (high: 12% vs 9%, intermediate: 4% vs 1%). Upstaging was more common with PSMA PET/CT than WBBS (P = 0.001). The maximum standardised uptake value (SUVmax ) of the primary tumour was associated with upstaging of skeletal metastases on PSMA PET/CT (P = 0.025), while age was associated with upstaging on WBBS (P = 0.021). The SUVmax of the primary tumour and metastases were both higher according to extent of metastatic disease (P = 0.001 and P < 0.001, respectively). CONCLUSIONS: More skeletal metastases were detected with PSMA PET/CT than WBBS, resulting in a higher upstaging rate mostly in high-risk patients. The SUVmax of the primary tumour and metastases was associated with upstaging.

Bladder infusion versus standard catheter removal for trial of void: a systematic review and meta-analysis.

PURPOSE: To compare the efficacy and time-to-discharge of two methods of trial of void (TOV): bladder infusion versus standard catheter removal. METHODS: Electronic searches for randomized controlled trials (RCTs) comparing bladder infusion versus standard catheter removal were performed using multiple electronic databases from dates of inception to June 2020. Participants underwent TOV after acute urinary retention or postoperatively after intraoperative indwelling catheter (IDC) placement. Quality assessment and meta-analyses were performed, with odds ratio and mean time difference used as the outcome measures. RESULTS: Eight studies, comprising 977 patients, were included in the final analysis. Pooled meta-analysis demonstrated that successful TOV was significantly higher in the bladder infusion group compared to standard TOV (OR 2.41, 95% CI 1.53-3.8, p = 0.0005), without significant heterogeneity (I2=19%). The bladder infusion group had a significantly shorter time-to-decision in comparison to standard TOV (weighted mean difference (WMD)-148.96 min, 95% CI - 242.29, - 55.63, p = 0.002) and shorter time-to-discharge (WMD - 89.68 min, 95% CI - 160.55, - 18.88, p = 0.01). There was no significant difference in complication rates between the two groups. CONCLUSION: The bladder infusion technique of TOV may be associated with a significantly increased likelihood of successful TOV and reduced time to discharge compared to standard TOV practices.

A prospective, matched comparison of ultra-low and standard-dose computed tomography for assessment of renal colic.

OBJECTIVE: To determine the diagnostic accuracy of ultra-low-dose computed tomography (ULDCT) compared with standard-dose CT (SDCT) in the evaluation of patients with clinically suspected renal colic, in addition to secondary features (hydroureteronephrosis, perinephric stranding) and additional pathological entities (renal masses). PATIENTS AND METHODS: A prospective, comparative cohort study was conducted amongst patients presenting to the emergency department with signs and symptoms suggestive of renal or ureteric colic. Patients underwent both SDCT and ULDCT. Single-blinded review of the image sets was performed independently by three board-certified radiologists. RESULTS: Among 21 patients, the effective radiation dose was lower for ULDCT [mean (SD) 1.02 (0.16) mSv] than SDCT [mean (SD) 4.97 (2.02) mSv]. Renal and/or ureteric calculi were detected in 57.1% (12/21) of patients. There were no significant differences in calculus detection and size estimation between ULDCT and SDCT. A higher concordance was observed for ureteric calculi (75%) than renal calculi (38%), mostly due to greater detection of calculi of <3 mm by SDCT. Clinically significant calculi (≥3 mm) were detected by ULDCT with high specificity (97.6%) and sensitivity (100%) compared to overall detection (specificity 91.2%, sensitivity 58.8%). ULDCT and SDCT were highly concordant for detection of secondary features, while ULDCT detected less renal cysts of <2 cm. Inter-observer agreement for the ureteric calculi detection was 93.9% for SDCT and 87.8% for ULDCT. CONCLUSION: ULDCT performed similarly to SDCT for calculus detection and size estimation with reduced radiation exposure. Based on this and other studies, ULDCT should be considered as the first-line modality for evaluation of renal colic in routine practice.

Long Pulse-Width Setting Improves Holmium-YAG Laser Lithotripsy - Enhanced Fragmentation and Retropulsion Characteristics of Renal Calculi in a Novel In-Vivo Setting.

The aim of this novel in vivo study was to characterize the effect of short pulse-width versus long pulse-width Holmium-YAG laser lithotripter settings on retropulsion and fragmentation in a real-life setting. A prospective, crossover study was conducted at a tertiary teaching hospital in NSW, Australia. Patients who underwent flexible ureteroscopy with laser lithotripsy for renal calculi in 2018 were included. All patients underwent flexible ureteroscopy using a Flexor® 10.7/12 French ureteric access sheath (Cook Medical LLC, Bloomington, IN, USA) and lithotripsy with a 30W Holmium-YAG laser (Rocamed, Monaco). Thirty-two renal calculi were subjected to 1 min of laser treatment using both short and long pulse-width settings. Using 5-point, operator-assessed Likert scales, the level of retropulsion and fragmentation efficacy were assessed. There was significantly less retropulsion and improved stone fragmentation (p<0.001) using the long pulse-width compared to the short pulse-width setting. Regardless of stone size, in vivo renal calculi lithotripsy with a long pulse-width significantly improves the efficacy of lithotripter treatment.

Single use versus reusable digital flexible ureteroscopes: A prospective comparative study.

OBJECTIVES: To compare the performance and surgical outcomes of two different single-use digital flexible ureteroscopes with a reusable video flexible ureteroscope. METHODS: Patients undergoing retrograde flexible ureteroscopy at Nepean Hospital, Sydney, Australia, were included in this study. Three different flexible ureteroscopes were used in this study: (i) single-use digital LithoVue (Boston Scientific, Marlborough, MA, USA); (ii) single-use digital PU3022A (Pusen, Zhuhai, China); and (iii) reusable digital URF-V2 (Olympus, Tokyo, Japan). Visibility and maneuverability was rated on a 5-point Likert scale by the operating surgeon. Operative outcomes and complications were collected and analyzed. RESULTS: A total of 150 patients were included in the present study. Of these, 141 patients had ureteroscopy for stone treatment, four for endoscopic combined intrarenal surgery and five for diagnostic/tumor treatment. There were 55 patients in the LithoVue group, 31 in the PU3022A group and 64 patients in the Olympus URF-V2 group. The URF-V2 group had higher visibility scores than both the single-use scopes and higher maneuverability scores when compared with the PU3022A. The LithoVue had higher visibility and maneuverability scores when compared with the PU3022A. There were no differences in operative time, rates of relook flexible ureteroscopes, scope failure or complication rates observed. CONCLUSIONS: Single-use digital flexible ureteroscopes have visibility and maneuverability profiles approaching that of a reusable digital flexible ureteroscope. Single-use flexible ureteroscopes achieve similar clinical outcomes to the more expensive reusable versions.

A study on the effect of the internal exposure to (210)Po on the excretion of urinary proteins in rats.

This study was designed to assess the feasibility of a noninvasive urine specimen for the detection of proteins as indicators of internal exposure to ionizing radiation. Three groups of rats (five in each group) were intravenously injected with 1601 ± 376, 10,846 ± 591 and 48,467 ± 2812 Bq of (210)Po in citrate form. A sham-exposed control group of five rats was intravenously injected with sterile physiological saline. Daily urine samples were collected over 4 days following injection. Purification and pre-concentration of urinary proteins were carried out by ultrafiltration using a 3000 Da molecular weight cutoff membrane filter. The concentration of common urinary proteins, namely albumin, alpha-1-acid glycoprotein, immunoglobulins IgA and IgG, was measured by an enzyme-linked immunosorbent assay. Urinary excretion of albumin decreased dose-dependently (p < 0.05) 96 h post-injection relative to the control group. In contrast, no statistically significant effects were observed for other proteins tested. The dose-dependent decrease in urinary excretion of albumin observed in this study underscores the need for further research, which may lead to the discovery of new biomarkers that would reflect the changes in the primary target organs for deposition of (210)Po.

Could Use of a Flexible and Navigable Suction Ureteral Access Sheath Be a Potential Game-changer in Retrograde Intrarenal Surgery? Outcomes at 30 Days from a Large, Prospective, Multicenter, Real-world Study by the European Association of Urology Urolithiasis Section.

BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate the stone-free status (SFS) rate and complications after flexible ureteroscopy (fURS) for treatment of renal stones using a flexible and navigable suction (FANS) ureteral access sheath. METHODS: Data for adults undergoing fURS in 25 centers worldwide were prospectively collected (August 2023 to January 2024). Exclusion criteria were abnormal renal anatomy and ureteral stones. All patients had computed tomography scans before and within 30 d after fURS with a FANS ureteral access sheath. SFS was defined as follows: grade A, zero fragments; grade B, a single fragment ≤2 mm; grade C, a single fragment 2.1-4 mm; and grade D, single/multiple fragments >4 mm. Data for continuous variables are presented as the median and interquartile range (IQR). Multivariable logistic regression was performed to evaluate predictors of grade A SFS. KEY FINDINGS AND LIMITATIONS: The study enrolled 394 patients (59.1% male) with a median age of 49 yr (IQR 36-61). The median stone volume was 1260 mm3 (IQR 706-1800). Thulium fiber laser (TFL) was used in 45.9% of cases and holmium laser in the rest. The median lasing time was 18 min (IQR 11-28) and the median operative time was 49 min (IQR 37-70). One patient required a blood transfusion and 3.3% of patients had low-grade fever. No patient developed sepsis. Low-grade ureteral injury occurred in eight patients (2%). The grade A SFS rate was 57.4% and the grade A + B SFS rate was 97.2%, while 2.8% of patients had grade C or D SFS. Eleven patients underwent repeat fURS. Multivariable analysis revealed that a stone volume of 1501-3000 mm3 (odds ratio 0.50) and of >3000 mm3 (odds ratio 0.29) were significantly associated with lower probability of grade A SFS, while TFL use was associated with higher SFS probability (odds ratio 1.83). Limitations include the lack of a comparative group. CONCLUSIONS AND CLINICAL IMPLICATIONS: fURS using a FANS ureteral access sheath resulted in a high SFS rate with negligible serious adverse event and reintervention rates. PATIENT SUMMARY: We looked at 30-day results for patients undergoing telescopic laser treatment for kidney stones using a special type of vacuum-assisted sheath to remove stone fragments. We found a high stone-free rate with minimal complications.

Distinct roles for motor cortical and thalamic inputs to striatum during motor skill learning and execution.

The acquisition and execution of motor skills are mediated by a distributed motor network, spanning cortical and subcortical brain areas. The sensorimotor striatum is an important cog in this network, yet the roles of its two main inputs, from motor cortex and thalamus, remain largely unknown. To address this, we silenced the inputs in rats trained on a task that results in highly stereotyped and idiosyncratic movement patterns. While striatal-projecting motor cortex neurons were critical for learning these skills, silencing this pathway after learning had no effect on performance. In contrast, silencing striatal-projecting thalamus neurons disrupted the execution of the learned skills, causing rats to revert to species-typical pressing behaviors and preventing them from relearning the task. These results show distinct roles for motor cortex and thalamus in the learning and execution of motor skills and suggest that their interaction in the striatum underlies experience-dependent changes in subcortical motor circuits.

The basal ganglia control the detailed kinematics of learned motor skills.

The basal ganglia are known to influence action selection and modulation of movement vigor, but whether and how they contribute to specifying the kinematics of learned motor skills is not understood. Here, we probe this question by recording and manipulating basal ganglia activity in rats trained to generate complex task-specific movement patterns with rich kinematic structure. We find that the sensorimotor arm of the basal ganglia circuit is crucial for generating the detailed movement patterns underlying the acquired motor skills. Furthermore, the neural representations in the striatum, and the control function they subserve, do not depend on inputs from the motor cortex. Taken together, these results extend our understanding of the basal ganglia by showing that they can specify and control the fine-grained details of learned motor skills through their interactions with lower-level motor circuits.

68Ga-PSMA PET/CT versus CT and bone scan for investigation of PSA failure post radical prostatectomy.

OBJECTIVE: To evaluate the use of Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography (68Ga-PSMA PET/CT), compared with conventional CT abdomen/pelvis (CTAP) and whole body single photon emission CT bone scan (BS), for detection of local or distant metastasis following biochemical failure/recurrence in post-prostatectomy patients. METHODS: We conducted a review of our prospectively maintained, institutional database to identify 384 patients with post-prostatectomy biochemical failure/recurrence who underwent PSMA PET/CT, CTAP and BS from February 2015 to August 2017 in Nepean Hospital, tertiary referral centre. The results of the three imaging modalities were analysed for their ability to detect local recurrence and distant metastases. PSMA PET/CT and CTAP imaging were separately performed on the same day and the BS was performed within several days (mostly in 24 h). Difference in detection rates was determined between the modalities and the Chi square test was used to determine significance. RESULTS: A total of 384 patients were identified with a median prostate-specific antigen (PSA) of 0.465 ng/mL (interquartile range =0.19-2.00 ng/mL). Overall, PSMA PET/CT was positive for 245 (63.8%) patients whereas CTAP and BS were positive in 174 patients (45.3%). A total of 98 patients (25.5%) had local or distant metastasis detected on PSMA only, while 20 patients (5.2%) had recurrences detected on CTAP but not on PSMA PET/CT. CONCLUSION: The use of PSMA PET/CT has a higher detection rate of predicted local or distant metastasis compared to CTAP and BS in the staging of patients with biochemical recurrences after radical prostatectomy.

Comparison of the thermal and histopathological effects of bipolar and monopolar electrosurgical resection of the prostate in a canine model.

OBJECTIVES: To compare the thermal and histopathological effects of two commercially available bipolar systems and conventional monopolar transurethral resection of the prostate (TURP) in a canine model. Bipolar TURP is an alternative to monopolar electrosurgery for treating benign prostatic hyperplasia and has several potential clinical advantages, including the ability to use normal saline irrigation, enhanced haemostasis and less collateral thermal damage. MATERIAL AND METHODS: In all, 12 adult male beagles were studied. After midline laparotomy and exposure of the bladder and prostate, two fibre-optic thermosensors were placed to record tissue temperatures; one sensor was placed into the substance of the prostate 2 cm from the urethra and the second in the prostatic-rectal groove on the capsular surface of the prostate to measure temperatures in the region of the neurovascular bundles. Through a midline cystotomy, antegrade TURP was performed using two different bipolar systems (Gyrus PlasmaKinetic and Vista, both from Gyrus-ACMI Corporation, Maple Grove, MN, USA) or a monopolar device (Force(TM) 2, Valleylab, Boulder, CO, USA). TURP was performed in each lateral lobe using 24 F resection loops. The dogs were humanely killed acutely and the prostates excised for histopathological assessment. RESULTS: When comparing intraprostatic temperature data, the mean (sem) temperature changes recorded for the monopolar group were significantly higher than in either the Gyrus or Vista bipolar groups, at 24.2 (3.9) degrees C vs 8.1 (1.5) degrees C and 6.8 (1.8) degrees C, respectively (P < 0.001). No measurable temperature elevations were recorded near the neurovascular bundles with any of the electrosurgery devices. The depth of thermal damage was greatest in the monopolar group at 0.59 (0.27) mm compared with the Gyrus and Vista groups at 0.07 (0.08) mm and 0.15 (0.02) mm, respectively (P < 0.001). CONCLUSION: Bipolar TURP generated significantly less heat and histopathological evidence of thermal damage compared with monopolar TURP in the present canine model.

A Systematic Review and Meta-Analysis of Pelvic Drain Insertion After Robot-Assisted Radical Prostatectomy.

Purpose: To perform a systematic review and meta-analysis and to assess the clinical benefit of prophylactic pelvic drain (PD) placement after robot-assisted laparoscopic prostatectomy (RALP) with pelvic lymph node dissection (PLND) in patients with localized prostate cancer. Materials and Methods: An electronic search of databases, including Scopus, Medline, and EMbase, was conducted for articles that considered postoperative outcomes with PD placement and without PD (no drain) placement after RALP. The primary outcome was rate of symptomatic lymphocele (requiring intervention) and secondary outcomes were complications as described by the Clavien-Dindo classification system. Quality assessment was performed using the Modified Cochrane Risk of Bias Tool for Quality Assessment. Results: Six relevant articles comprising 1783 patients (PD = 1253; ND = 530) were included. Use of PD conferred no difference in symptomatic lymphocoele rate (risk difference 0.01; 95% confidence interval [CI] -0.007 to 0.027), with an overall incidence of 2.2% (95% CI 0.013-0.032). No difference in low-grade (I-II; risk difference 0.035, 95% CI -0.065 to 0.148) or high-grade (III-V; risk difference -0.003, 95% CI -0.05 to 0.044) complications was observed between PD and ND groups. Low-grade (I-II) complications were 11.8% (95% CI 0-0.42) and 7.3% (95% CI 0-0.26), with similar rates of high-grade (III-V) complications, being 4.1% (95% CI 0.008-0.084) and 4.3% (95% CI 0.007-0.067) for PD and ND groups, respectively. Conclusion: PD insertion after RALP with extended PLND did not confer significant benefits in prevention of symptomatic lymphocoele or postoperative complications. Based on these results, PD insertion may be safely omitted in uncomplicated cases after consideration of clinical factors.

Anti-adhesive coating and clearance of device associated uropathogenic Escherichia coli cystitis.

PURPOSE: A previous study showed decreased uropathogen adherence using a novel anti-fouling coating consisting of mussel adhesive protein mimics conjugated to poly(ethylene glycol). We assessed the ability of methoxy polyethylene glycol-dihydroxyphenylalanine (Nerites Corp. Ltd., Madison, Wisconsin) coated ureteral stents to resist bacterial adherence, infection development and encrustation in a rabbit model of uropathogenic Escherichia coli cystitis. MATERIALS AND METHODS: Sof-Flex stent curls that were uncoated and coated with 3 coatings, including Surphys 002, 008 and 009, respectively, and uncoated Percuflex Plus stents were inserted transurethrally into the bladder of 50 male New Zealand White rabbits (Charles River Laboratories, Montreal, Quebec, Canada), followed by instillation of uropathogenic E. coli strain GR12 (10(7) cfu). Urine was examined for bacteria on days 0, 1, 3 and 7, and for cytokine levels on day 7. On day 7 the animals were sacrificed. Stent curls and bladders were harvested for analysis. In a parallel experiment stents were challenged in vitro for 7 days with GR12 in human urine. RESULTS: Surphys 009 coated devices showed decreased urine and stent bacterial counts compared to those in controls. Eight of 10 rabbits in the Surphys 009 group had sterile urine by day 3 vs 1 in each control group (p = 0.013), while stent adherent organisms were decreased by more than 75%. While no statistical differences were found in encrustation and bladder inflammation across the groups, immune scoring was lowest in the uncoated Sof-Flex control and Surphys 009 groups (p = 0.030). CONCLUSIONS: Surphys 009 strongly resisted bacterial attachment, resulting in improved infection clearance over that of uncoated devices. However, this did not translate to decreased encrustation, which appeared to be independent of infection in this model.

Percutaneous nephrolithotomy made easier: a practical guide, tips and tricks.

Percutaneous nephrolithotomy (PCNL) plays an integral role in managing large renal stones. Establishing percutaneous renal access is the most crucial step in the procedure and requires a thorough understanding of renal, retroperitoneal and thoracic anatomy to minimize the risk of complications. Moreover, access to fluoroscopy and the proper equipment are critical to ensuring complete stone removal. In this review we describe the technique of PCNL used in a high-volume endourology centre, where the urologist is involved in all aspects of the procedure.

A Rare Case of Ureteral IgG4 Disease Masquerading as Urothelial Carcinoma.

The present paper described a rare case of ureteral IgG4-related disease (IgG4-RD) that mimicked urothelial carcinoma. An otherwise healthy patient presented with computed tomography, ureteroscopic, and biopsy findings that were suspicious of urothelial carcinoma. The patient received a right nephroureterectomy. Histopathology showed ureteral IgG4-RD, without evidence of urothelial carcinoma. Accurate diagnosis of this rare entity should be based on clinical, biochemical, and histopathological findings.

ENCAPSULATED 3,4,3-LI(1,2-HOPO) IN CHITOSAN NANOPARTICLES FOR DECORPORATION VIA INHALATION.

3,4,3-LI(1,2-HOPO) has been identified as an excellent alternative for DTPA for decorporating actinides, such as Pu and Am, after internal contamination. Efforts have been focused on its application through oral administration. When 3,4,3-LI(1,2-HOPO) was encapsulated with biocompatible, biodegradable nanoparticles made of chitosan, its release from the nanoparticles to lung fluid, observed in in vitro experiments, exhibited an extended release profile. These observations were very encouraging, as this nanomedicine could lead to a reduction in the dosing frequency required to achieve the decorporation efficacy of unformulated 3,4,3-LI(1,2-HOPO) itself. In vivo release tests as well as actinide decorporation experiments, using an inhalation exposure animal model, will follow.

Transitional-cell carcinoma recurrence rate after nephroureterectomy in patients who undergo open excision of bladder cuff v transurethral incision of the ureteral orifice.

BACKGROUND AND PURPOSE: The gold standard treatment for upper-tract transitional-cell carcinoma is radical nephroureterectomy, but management of the distal ureter is not standardized. Two treatment options to detach the distal ureter are open cystotomy (OC) and excision of a bladder cuff or transurethral incision of the ureteral orifice (TUIUO). We compared the clinico-pathologic outcomes of these two techniques. PATIENTS AND METHODS: Hospital records were reviewed on all 51 patients who had undergone open or laparoscopic nephroureterectomy at our institution between 1 January 1990 and 30 June 2005. Patient demographics, intraoperative parameters, and pathology data were collected. The mean follow-up was 23.2 months (range 4.5-75 months) and 22.1 months (range 1-50 months) for the OC and TUIUO groups, respectively. There were no significant differences in sex, age at operation, American Society Anesthesiologists risk score, previous transitional-cell tumors, pathologic tumor grade and stage, or metastatic disease status in the two groups. RESULTS: Five patients had an unplanned incomplete ureterectomy. The bladder recurrence rates were similar in the OC group (22.2%; 6/27) and the TUIUO group (26.3%; 5/19). There were no pelvic recurrences in either group. Four of the five patients who had an incomplete ureterectomy had tumor recurrences, three in the form of metastatic disease. CONCLUSION: Management of the distal ureter by TUIUO in appropriate patients offers the same rate of bladder recurrence as OC. Incomplete ureterectomy results in a significantly higher rate of recurrence, often associated with the development of metastatic disease.

Antegrade percutaneous endopyelotomy.

Ureteropelvic junction obstruction (UPJO) is a well-known pathologic condition with several potential associated urologic complications. The treatment for UPJO has evolved dramatically during the past two decades with the advent of minimally invasive treatment options. This has resulted in shorter hospital stays, reduced postoperative pain, and quicker convalescence compared with the gold standard, open pyeloplasty. Antegrade (percutaneous) endopyelotomy is one of the many minimally invasive treatment options for this disorder. In this article, we review the technical aspects, outcomes, and current role of antegrade endopyelotomy in the treatment of UPJO.

GHSI EMERGENCY RADIONUCLIDE BIOASSAY LABORATORY NETWORK - SUMMARY OF THE SECOND EXERCISE.

The Global Health Security Initiative (GHSI) established a laboratory network within the GHSI community to develop collective surge capacity for radionuclide bioassay in response to a radiological or nuclear emergency as a means of enhancing response capability, health outcomes and community resilience. GHSI partners conducted an exercise in collaboration with the WHO Radiation Emergency Medical Preparedness and Assistance Network and the IAEA Response and Assistance Network, to test the participating laboratories (18) for their capabilities in in vitro assay of biological samples, using a urine sample spiked with multiple high-risk radionuclides (90Sr, 106Ru, 137Cs, and 239Pu). Laboratories were required to submit their reports within 72 h following receipt of the sample, using a pre-formatted template, on the procedures, methods and techniques used to identify and quantify the radionuclides in the sample, as well as the bioassay results with a 95% confidence interval. All of the participating laboratories identified and measured all or some of the radionuclides in the sample. However, gaps were identified in both the procedures used to assay multiple radionuclides in one sample, as well as in the methods or techniques used to assay specific radionuclides in urine. Two-third of the participating laboratories had difficulties in determining all the radionuclides in the sample. Results from this exercise indicate that challenges remain with respect to ensuring that results are delivered in a timely, consistent and reliable manner to support medical interventions. Laboratories within the networks are encouraged to work together to develop and maintain collective capabilities and capacity for emergency bioassay, which is an important component of radiation emergency response.