Linear relationship between absorbed radiation dose and pulse rate during fluoroscopy.

PURPOSE: To identify the relationship between fluoroscopy pulse rate and absorbed radiation dose. We compared absorbed radiation dose with common proxy measurements such as fluoroscopy time and C-arm reported dose. METHODS: Using a simulated patient model, 60 s fluoroscopy exposures were performed using pulse rates of 30, 8, 4, 2, and 1 pulse(s) per second. Each experiment was performed with both standard and low-dose settings using a GE OEC 9800 plus C-arm. Landauer nanoDot™ OSL dosimeters were used to measure the absorbed radiation dose. RESULTS: Fluoroscopy pulse rate and absorbed radiation dose demonstrated a linear correlation for both standard (R2 = 0.995, p < 0.001) and low-dose (R2 = 0.998, p < 0.001) settings. For any given pulse rate, using the low-dose setting reduced absorbed radiation dose by 58 ± 2.8%. Fluoroscopy time demonstrated a linear relationship with absorbed radiation dose for both standard (R2 = 0.996, p < 0.001) and low-dose (R2 = 0.991, p < 0.001) settings, but did not change with use of the low-dose setting. C-arm reported radiation dose correlated linearly with absorbed dose (R2 = 0.999) but consistently under-estimated measured values by an average of 49 ± 3.5%. Using a combination of 1 pulse-per-second and low-dose fluoroscopy, absorbed dose was reduced by 97.7 ± 0.1% compared to standard dose and 30 pulse-per-second settings. CONCLUSION: Absorbed radiation dose decreases linearly with fluoroscopy pulse rate during equivalent exposure times. Adjusting fluoroscopy pulse rate and utilizing low-dose settings significantly reduces overall absorbed radiation exposure by up to 98%.

Strong Conflict of Interest Policies are not Associated With Decreased Industry Payments to Academic Urology Departments.

OBJECTIVE: To identify whether institutions with strong conflicts of interest (COI) policies receive less industry payments than those with weaker policies. While industry-physician interactions can have collaborative benefits, financial COI can undermine preservation of the integrity of professional judgment and public trust. To address this concern, academic institutions have adopted COI policies. It is unclear whether the strength of COI policy correlates with industry payments in urology. MATERIALS AND METHODS: 131 US academic urology programs were surveyed on their COI policies, and graded according to the American Medical Student Association (AMSA) criteria. Strength of COI policy was compared against industry payments in the Center for Medicare and Medicaid Services Open Payments database. RESULTS: Fifty-seven programs responded to the survey, for a total response rate of 44%. There was no difference between COI policy groups on total hospital payments (P = .05), total department payments (P = .28), or dollars per payment (P = .57). On correlation analysis, there was a weak but statistically nonsignificant correlation between AMSA Industry Policy Survey Score and Open Payments payments (ρ = -0.14, P = .32). CONCLUSION: Strength of conflicts of interest policy in academic urology did not correlate to industry payments within the Open Payments database. Establishment of strong COI policy may create offsetting factors that mitigate the intended effects of the policy. Further studies will be required to develop the evidence base for policy design and implementation across various specialties.

Modeling the Incidence of Secondary Malignancy Related to Ionizing Radiation Use in the Management of Nephrolithiasis.

OBJECTIVE: To model the risk of secondary malignancy and associated mortality due to ionizing radiation from the evaluation and management of nephrolithiasis. METHODS: A PUBMED-based literature search was performed to identify model inputs, specifically annual incidence of nephrolithiasis sub-stratified by age and gender and radiation exposure associated with nephrolithiasis episodes. Estimates of age and gender specific radiation-induced malignancy and mortality rates were obtained from the BEIR VII Phase 2 report with dose extrapolation using the linear no-threshold model. RESULTS: Incidence of new diagnoses of nephrolithiasis ranged from 42/100,000 in males 20-30 years old to 248/100,000 in males 60-70 years old. Radiation exposure per nephrolithiasis episode was 37.3 mSv over a 2-year period. Data regarding average stone episodes per patient with nephrolithiasis was limited and conservatively estimated at 1.5. Modeled lifetime attributable risk of secondary malignancy and subsequent mortality in individual stone patients ranged from 0.096% and 0.085%, respectively, in males over the age of 70 to 0.59% and 0.39% in females 20-30 years old. In the USA, overall incidence of secondary malignancy and associated mortality related to nephrolithiasis management was calculated to be 862.7 and 545.3 cases/year, respectively. CONCLUSION: This model suggests that ionizing radiation from the management of nephrolithiasis carries a small but significant risk of causing secondary malignancy. This knowledge must be considered when using modalities that involve radiation in the diagnosis and therapeutic management of nephrolithiasis.

Cowper's Gland Syringocele.

Cowper's gland syringoceles are rare cystic dilations of the Cowper's gland duct. They are typically diagnosed in childhood but occasionally occur in adults. We report the case of a 28-year-old man who presented with a painful perineal and inferior scrotal mass and was found to have a large Cowper's gland syringocele extending into the scrotum associated with a scrotal abscess. Treatment consisted of surgical excision. The magnetic resonance imaging findings of this case are described.

Single Pulse-per-second Setting Reduces Fluoroscopy Time During Ureteroscopy.

OBJECTIVE: To evaluate the effect of 1 pulse-per-second (pps) fluoroscopy on fluoroscopy time and surgeon radiation exposure during ureteroscopy. MATERIALS AND METHODS: A retrospective review of a single endourologist's operative records was performed over a 12-month period. Adult patients undergoing ureteroscopy were included. At the 6-month point, the switch from continuous "low-dose" to 1 pps "low-dose" fluoroscopy was made. Surgeon radiation exposure was measured using 1 dosimeter placed at the torso under the lead apron and 1 dosimeter overlying the chest outside the lead apron. RESULTS: A total of 84 and 70 patients underwent ureteroscopy using continuous and 1 pps fluoroscopy, respectively. No differences were identified between the 2 groups with regard to patient age (P = .96), sex (P = .26), body mass index (P = .95), stone multiplicity (P = .31), bilateral ureteroscopy (P = .07), pre-stenting (P = .99), staged (P = .84) or failed (P = .99) primary ureteroscopy, ureteral access sheath utilization (P = .10), or case duration (P = .54). Patients in the 1 pps cohort had a larger median stone burden (P = .04). The median fluoroscopy time was reduced from 77 (interquartile range: 54-115) to 16 seconds (interquartile range: 13-24) using 1 pps fluoroscopy (P < .001). Monthly surgeon radiation exposure was reduced by 64%, from 6.8 ± 8.3 to 1.8 ± 2.7 mRad deep dose equivalent (P = .11), from 120.6 ± 101.4 to 49.2 ± 66.6 mRad lens dose equivalent (P = .10), and from 116.2 ± 97.8 to 47.6 ± 64.0 mRad shallow dose equivalent (P = .11). Reversion to continuous fluoroscopy was never required during the study period. CONCLUSION: Single pps fluoroscopy is feasible, significantly reduces fluoroscopy time, and lowers surgeon radiation exposure by 64%.

Appearance of Pyelitis Emphysematosa on Computed Tomography.

Pyelitis emphysematosa is a gas-forming infection characterized by gas located within the wall of the collecting system and renal pelvis. There are only 2 reported cases of pyelitis emphysematosa in the literature, neither of which occurred in the era of cross-sectional imaging. Here we present a case of pyelitis emphysematosa occurring in an elderly female with congenital left renal atrophy and chronic right hydronephrosis secondary to ureteropelvic junction obstruction.

Biopsy Perineural Invasion in Prostate Cancer Patients Who Are Candidates for Active Surveillance by Strict and Expanded Criteria.

OBJECTIVE: To evaluate the association of biopsy perineural invasion (PNI) with adverse pathologic findings on radical prostatectomy in patients who would have been candidates for active surveillance (AS). METHODS: Using a prospectively populated database of 3084 men who underwent open radical prostatectomy, candidates for AS by strict (Johns Hopkins) and expanded (University of Toronto) criteria were identified. The presence of adverse pathologic features at radical prostatectomy was compared between those men with and without biopsy PNI. RESULTS: Of 596 men who met strict criteria for AS, 16 (3%) had biopsy PNI. In the strict AS cohort, there were no differences in adverse pathologic features at radical prostatectomy between those with and without PNI. Of 1197 men who were candidates for AS by expanded criteria, 102 (9%) had biopsy PNI. Men with biopsy PNI in the expanded AS cohort were more likely to have extraprostatic extension (P < .001) and pathologic upgrading (P = .01) at prostatectomy. In addition, those with PNI had larger dominant nodules (P < .001), and cancer comprised a greater percentage of their prostate glands (P < .001). There was no difference in the proportion with a positive margin between the 2 groups (P = .77). CONCLUSION: Biopsy PNI was rare in patients who met strict criteria for AS. Among those men who met expanded criteria, PNI was associated with adverse pathologic findings upon prostatectomy. The presence of biopsy PNI may have a role in further risk stratifying patients who meet expanded criteria for AS.