Geothermal application of spectral gamma ray logging in the South Kansas Subsurface, USA.

Spectral gamma ray (SGR) is a logging tool that allows computation of the radioactive heat produced through radioactive decay of uranium, thorium and potassium within rocks. Radioactive heat-producing rocks are common targets for geothermal exploration. Gamma rays have longer half-length life in comparison to other radiations generated during radioactive decay. This characteristic allows the gamma rays to permeate far enough through the media to be measured by a logging tool. Radioactive heat production in this study was computed using spectral gamma ray and density logs. High-temperature geothermal reservoirs could provide heat that could be used to produce electricity from steam turbines. To provide domestic hot water, space heating, or process hot water, both low- and high-temperature geothermal systems could be used. This article is a case study illustrating subsurface radioactive heat production (A) calculated using well log data recorded in 48 wells located at 16 counties in the South Kansas State, USA. The results show that radioactive heat production (A) varies from approximately 0.1 to more than 10 µW/m3, whereas the average arithmetic mean is 1.15 µW/m3 and the average standard deviation is 0.57 µW/m3, which varies with lithology. The high measurements of radioactive heat production (A) in the studied rocks are predominantly related to the respective increase in uranium content in both shale and carbonate formations that could be future geothermal targets.

The role of voiding cystourethrography in asymptomatic unilateral isolated ureteropelvic junction obstruction: A retrospective study.

INTRODUCTION: The presence of concomitant vesicoureteric reflux (VUR) and ureteropelvic junction obstruction (UPJO) is uncommon. Nevertheless, the reported VUR coexisting with asymptomatic unilateral isolated hydronephrosis (AUIH) requiring pyeloplasty for correction of UPJO was of low grade and mostly resolved during conservative follow-up. Therefore, VCUG may be not indicated in these children except if voiding symptoms, urinary tract infection (UTI), dilated ureters, or bladder and ureteric abnormalities are suspected. OBJECTIVES: The aim was to evaluate the need for VCUG in infants <1 year old with AUIH for whom a dismembered pyeloplasty was indicated for correction of UPJO. METHODS: Ninety-six children <1 year old with pyeloplasty carried out from January 2012 to March 2014 were retrospectively included. Children with voiding symptoms or dilated ureter, duplex system, fused kidneys, bilateral dilatation, or any bladder abnormality on ultrasound were excluded. Anderson-Hynes pyeloplasty was performed through a flank incision. Preoperative VCUG was analyzed in relation to outcome and any UTI during follow-up. The Student t test, Mann-Whitney U test, or Fisher exact test were used to compare variables. RESULTS: Five children had concomitant VUR with UPJO. Most of the children were circumcised during the first postnatal week. The remaining few children were circumcised at the time of pyeloplasty. Side, grade of detected VUR, and complications (18.75%) (postoperative or during follow-up) are presented in the Table. Outcomes in children with and without VUR were not different. Dismembered pyeloplasty was successful in children with VUR and with no complications except for non-febrile UTI in one child only. Ureters were still not dilated at the last follow-up. DISCUSSION: The required imaging in infants with AUIH is still a subject of debate. As we expected, there was a low incidence of associated VUR in the present study. They were of low grade without any complications during follow-up and without affecting the outcome. The present study has its limitations, including the retrospective nature and short follow-up. However, as at least 2 years of follow-up were documented without any harm or ureteric dilation, VUR will mostly resolve. The present study is strengthened by inclusion of infants only. CONCLUSIONS: Our data suggest that VCUG is not indicated in infants with AUIH requiring pyeloplasty for correction of UPJO. VCUG will not affect the treatment decision, operative outcome, or postoperative complications. VCUG may be indicated in case of suspected voiding symptoms, UTI, dilated ureters, or bladder and ureteric abnormalities.

Dismembered Pyeloplasty in Infants 6 Months Old or Younger With and Without External Trans-anastomotic Nephrostent: A Prospective Randomized Study.

OBJECTIVE: To compare the outcome of dismembered pyeloplasty in infants with and without external nephro-ureteric stent (ENUS) for treatment of congenital ureteropelvic junction obstruction. METHODS: This is a parallel, randomized comparative study between October 2013 and September 2014. Thirty infants ≤6 months old with ureteropelvic junction obstruction indicated for dismembered pyeloplasty were randomly assigned (block randomization, closed envelope method) into two groups: group A (stentless) and group B (ENUS). Infants with solitary kidney, gross pyuria, huge pelvis, vesicoureteric reflux, or other renal anomalies were excluded. Operative data, complications, and ultrasonographic and nuclear scintigraphy criteria were compared after at least 18 months of follow-up using Student t, Mann-Whitney U, Kruskal-Wallis, chi-square, and Fisher exact tests when appropriate. Occurrence of urinary leakage was the primary outcome. RESULTS: Included patients completed the study with intention-to-treat analysis. All children had normal renal function. The mean operative time was 85.3 ± 6.3 (60-90) minutes in group A and 92.6 ± 15.3 (70-120) minutes in group B (P = .2). Although there was a significant postoperative improvement in each group in split renal function and anterior-posterior renal pelvis diameter, there was no significant difference between both groups. The mean hospital stay for group A and group B was 5.9 ± 2 (4-10) days versus 3.5 ± 0.8 (2-5) days, respectively (P < .001). Postoperative urinary leakage was reported only in group A (40%). All complications were managed by double J insertion. Auxiliary interventions were higher in group A. The overall success rate was 93.4%. Redo pyeloplasty was performed in one case in each group. CONCLUSION: ENUS significantly reduces hospital stay and complications. It saves the infant hazards of auxiliary interventions under general anesthesia for management of leakage or double J removal if placed at time of pyeloplasty.