Thomas Leippold

Optimization of the artificial urinary sphincter: modelling and experimental validation

The artificial urinary sphincter should be long enough to prevent strangulation effects of the urethral tissue and short enough to avoid the improper dissection of the surrounding tissue. To optimize the sphincter length, the empirical three-parameter urethra compression model is proposed based on the mechanical properties of the urethra: wall pressure, tissue response rim force and sphincter periphery length. In vitro studies using explanted animal or human urethras and different artificial sphincters demonstrate its applicability. The pressure of the sphincter to close the urethra is shown to be a linear function of the bladder pressure. The force to close the urethra depends on the sphincter length linearly. Human urethras display the same dependences as the urethras of pig, dog, sheep and calf. Quantitatively, however, sow urethras resemble best the human ones. For the human urethras, the mean wall pressure corresponds to (−12.6 ± 0.9) cmH2O and (−8.7 ± 1.1) cmH2O, the rim length to (3.0 ± 0.3) mm and (5.1 ± 0.3) mm and the rim force to (60 ± 20) mN and (100 ± 20) mN for urethra opening and closing, respectively. Assuming an intravesical pressure of 40 cmH2O, and an external pressure on the urethra of 60 cmH2O, the model leads to the optimized sphincter length of (17.3 ± 3.8) mm.

Sacral magnetic stimulation in non-inflammatory chronic pelvic pain syndrome

To prospectively evaluate sacral magnetic high‐frequency stimulation as a treatment option for patients with non‐inflammatory chronic pelvic pain syndrome (CPPS, category IIIB).

Prostate biopsy in Switzerland: a representative survey on how Swiss urologists do it.

Objective. The procedure of prostate biopsy is often performed but has not been standardized. Therefore, a survey of all urologists in Switzerland was carried out to investigate indications, patient preparation and technique with regard to transrectal prostate biopsy. Material and methods. A questionnaire was mailed to all 178 urologists working in Switzerland, either as self-employed urologists (SEUs) or as employed urologists at a hospital (EUHs), i.e. a teaching centre. Results. The questionnaire was returned by 133 urologists (75%). Eighty-seven of the respondents (65%) are SEUs and 46 (35%) work as EUHs. If digital rectal examination (DRE) raises suspicion of cancer, 129 urologists perform a biopsy. A serum prostate-specific antigen (PSA) level of 4 ng/ml is used as a cut-off value by 84% of respondents (SEUs 83%, EUHs 87%). A fluoroquinolone antibiotic is prescribed by 126 of the respondents. Fifty-nine percent of respondents (SEUs 52%, EUHs 72%) are offering periprostatic injection of a local anaesthetic drug. At the initial biopsy, 24% of respondents (SEUs 30%, EUHs 13%) obtain six cores, 45% (SEUs 37%, EUHs 61%) 8–10 and 17% (SEUs 18%, EUHs 15%) ≥12. The subsequent procedure performed after two negative biopsy sessions varies considerably. Conclusions. This survey provides an insight into the practice pattern of urologists in Switzerland concerning prostate biopsy. For almost all urologists, a positive DRE is an indication for prostate biopsy. The majority use a serum PSA level of 4 ng/ml as a cut-off value. A fluoroquinolone is the antibiotic of choice. Periprostatic nerve block is the commonest form of anaesthesia. Most urologists take 8–10 cores per biopsy.

Exposure of Treating Physician to Radiation during Prostate Brachytherapy Using Iodine-125 Seeds Dose Measurements on Both Hands with Thermoluminescence Dosimeters

Background and Purpose:Only sparse reports have been made about radiation exposure of the treating physician during prostate seed implantation. Therefore, thermoluminescence dosimeter (TLD) measurements on the index fingers and the backs of both hands were conducted.Material and Methods:Stranded iodine-125 seeds with a mean apparent activity of 27.4 MBq per seed were used. During application, the treating physician manipulated the loaded needle with the index fingers, partially under fluoroscopic control. Four physicians with varying experience treated 24 patients. The radiation exposure was determined with TLD-100 chips attached to the index fingertips and the backs of hands. Radiation exposure was correlated with the physician’s experience.Results:The average brachytherapy duration by the most experienced physician was 19.2 min (standard deviation σ = 1.2 min; novices: 34.8 min [σ = 10.2 min]). The mean activity was 1,703 MBq (σ = 123 MBq), applied with 16.3 needles (σ = 2.5 needles; novices: 1,469 MBq [σ = 229 MBq]; 16.8 needles [σ = 2.3 needles]). The exposure of the finger of the “active hand” and the back of the hand amounted to 1.31 mSv (σ = 0.54 mSv) and 0.61 mSv (σ = 0.23 mSv), respectively (novices: 2.07 mSv [σ = 0.86 mSv] and 1.05 mSv [σ = 0.53 mSv]).Conclusion:If no other radiation exposure needs to be considered, an experienced physician can perform about 400 applications per year without exceeding the limit of 500 mSv/year; for novices, the corresponding figure is about 200.Hintergrund und Ziel:Zur Strahlenexposition des applizierenden Arztes bei der Brachytherapie mit Iod-125-Seeds, insbesondere an den Fingern, existieren kaum Informationen. Mit TLD (Thermolumineszenzdosimeter) wurden deshalb Dosismessungen an den die Nadel führenden Zeigefingern und den Handrücken jeweils beider Hände durchgeführt (Abbildung 2) und mit der Erfahrung des Applizierenden korreliert.Material und Methodik:Es wurden Iod-125-Seedketten mit einer mittleren scheinbaren Aktivität von 27,4 MBq pro Seed verwendet (Tabelle 1). Während der Applikation manipulierte der Arzt die beladenen Nadeln mit den Zeigefingern, teilweise unter Durchleuchtung (Abbildung 1). Vier Ärzte mit unterschiedlicher Erfahrung behandelten 24 Patienten. Die Strahlenbelastung wurde mit TLD-100-Chips gemessen, welche auf beide Zeigefinger und die Handrücken aufgeklebt wurden (Abbildung 2).Ergebnisse:Eine Applikation des Arztes mit der größten Erfahrung dauerte durchschnittlich 19,2 min (Standardabweichung σ = 1,2 min), wobei er im Mittel 1 703 MBq (σ = 123 MBq) in 16,3 Nadeln (σ = 2,5 Nadeln) verwendete. Ein unerfahrener Operateur benötigte für eine Applikation von durchschnittlich 1 469 MBq (σ = 229 MBq) mit 16,8 Nadeln (σ = 2,3 Nadeln) im Mittel 34,8 min (σ = 10,2 min) (Abbildungen 3 und 4). Die beim erfahrenen Arzt gemessene mittlere Strahlenexposition des stärker belaste- ten Fingers betrug 1,31 mSv (σ = 0,54 mSv), jene des Handrückens 0,61 mSv (σ = 0,23 mSv). Die korrespondierenden Werte des unerfahrenen Operateurs lagen bei 2,07 mSv (σ = 0,86 mSv) bzw. 1,05 mSv (σ = 0,53 mSv) (Abbildungen 5, 6a und 6b.Schlussfolgerung:Ohne Berücksichtigung anderer Strahlenexpositionen kann ein erfahrener Arzt pro Jahr etwa 400, ein unerfahrener Arzt etwa 200 Applikationen durchführen, ohne den Dosisgrenzwert von 500 mSv/Jahr zu überschreiten.

Topological methods for the comparison of structures using LDR-brachytherapy of the prostate as an example

The dose coverage of low dose rate (LDR)-brachytherapy for localized prostate cancer is monitored 4-6 weeks after intervention by contouring the prostate on computed tomography and/or magnetic resonance imaging sets. Dose parameters for the prostate (V100, D90 and D80) provide information on the treatment quality. Those depend strongly on the delineation of the prostate contours. We therefore systematically investigated the contouring process for 21 patients with five examiners. The prostate structures were compared with one another using topological procedures based on Boolean algebra. The coincidence number C(V) measures the agreement between a set of structures. The mutual coincidence C(i, j) measures the agreement between two structures i and j, and the mean coincidence C(i) compares a selected structure i with the remaining structures in a set. All coincidence parameters have a value of 1 for complete coincidence of contouring and 0 for complete absence. The five patients with the lowest C(V) values were discussed, and rules for contouring the prostate have been formulated. The contouring and assessment were repeated after 3 months for the same five patients. All coincidence parameters have been improved after instruction. This shows objectively that training resulted in more consistent contouring across examiners.

MP12-10 RADIATION EXPOSURE TO MEDICAL STAFF IN THE UROLOGY OPERATING THEATRE – A PROSPECTIVE STUDY

INTRODUCTION AND OBJECTIVES: Fluoroscopic screening is essential in urological standard surgery. However, there is only limited and inconsistent data available on the level of radiation exposure to the medical staff in the operating theatre, thus raising concerns about immediate and late effects of exposure to X-rays. METHODS: In this prospective analysis, cumulative radiation doses were measured in a three months period from January to March 2013 in the urology operating theatre. All surgical procedures requiring fluoroscopic screening (Uroskop Access, Siemens) were included. Dosimeters (Dosilab ) were attached to the surgeon’s forehead and to the ring finger of the left hand. Radiation exposure of anesthesia staff was captured by a dosimeter that was placed on the surface of the respirator. In addition, general patient exposure in the areas outside the X-ray field was measured by a dosimeter positioned laterally of the patient’s pelvis. RESULTS: A total of 108 surgical procedures, among them 41 ureterorenoscopies, 34 ureteral stent insertions, and 33 not further specified procedures, were evaluated. The surgeon’s cumulative exposure to radiation during the entire study period and as measured via finger ring dosimeter was 6.2 mSv, at the forehead (cornea level) 1.1 mSv were measured. The general cumulative patient exposure amounted to 0.3 mSv. At the anesthesia work place, which is in about 3 meters distance from the fluoroscope, no radiation exposure was detected (0.0 mSv). CONCLUSIONS: Despite the regular need of fluoroscopic screening for diagnostic and therapeutic procedures in the urology operating theatre, cumulative radiation exposure to the surgeon’s cornea and fingers reached only one-hundredth of the maximum permissible annual dose. For the anesthesia staff as well as for the patient, no significant increase in cumulative dose was detected as compared to the natural background radiation. However, a responsible handling of the radiation source is an immediate requirement.

Exposure of Treating Physician to Radiation during Prostate Brachytherapy Using Iodine-125 Seeds@@@Strahlenexposition des applizierenden Arztes bei der Brachytherapie mit Iod-125-Seeds. Dosismessungen an beiden Händen mit Thermolumineszenzdosimetern: Dose Measurements on Both Hands with Thermoluminescence Dosimeters

Background and Purpose:Only sparse reports have been made about radiation exposure of the treating physician during prostate seed implantation. Therefore, thermoluminescence dosimeter (TLD) measurements on the index fingers and the backs of both hands were conducted.Material and Methods:Stranded iodine-125 seeds with a mean apparent activity of 27.4 MBq per seed were used. During application, the treating physician manipulated the loaded needle with the index fingers, partially under fluoroscopic control. Four physicians with varying experience treated 24 patients. The radiation exposure was determined with TLD-100 chips attached to the index fingertips and the backs of hands. Radiation exposure was correlated with the physician’s experience.Results:The average brachytherapy duration by the most experienced physician was 19.2 min (standard deviation σ = 1.2 min; novices: 34.8 min [σ = 10.2 min]). The mean activity was 1,703 MBq (σ = 123 MBq), applied with 16.3 needles (σ = 2.5 needles; novices: 1,469 MBq [σ = 229 MBq]; 16.8 needles [σ = 2.3 needles]). The exposure of the finger of the “active hand” and the back of the hand amounted to 1.31 mSv (σ = 0.54 mSv) and 0.61 mSv (σ = 0.23 mSv), respectively (novices: 2.07 mSv [σ = 0.86 mSv] and 1.05 mSv [σ = 0.53 mSv]).Conclusion:If no other radiation exposure needs to be considered, an experienced physician can perform about 400 applications per year without exceeding the limit of 500 mSv/year; for novices, the corresponding figure is about 200.Hintergrund und Ziel:Zur Strahlenexposition des applizierenden Arztes bei der Brachytherapie mit Iod-125-Seeds, insbesondere an den Fingern, existieren kaum Informationen. Mit TLD (Thermolumineszenzdosimeter) wurden deshalb Dosismessungen an den die Nadel führenden Zeigefingern und den Handrücken jeweils beider Hände durchgeführt (Abbildung 2) und mit der Erfahrung des Applizierenden korreliert.Material und Methodik:Es wurden Iod-125-Seedketten mit einer mittleren scheinbaren Aktivität von 27,4 MBq pro Seed verwendet (Tabelle 1). Während der Applikation manipulierte der Arzt die beladenen Nadeln mit den Zeigefingern, teilweise unter Durchleuchtung (Abbildung 1). Vier Ärzte mit unterschiedlicher Erfahrung behandelten 24 Patienten. Die Strahlenbelastung wurde mit TLD-100-Chips gemessen, welche auf beide Zeigefinger und die Handrücken aufgeklebt wurden (Abbildung 2).Ergebnisse:Eine Applikation des Arztes mit der größten Erfahrung dauerte durchschnittlich 19,2 min (Standardabweichung σ = 1,2 min), wobei er im Mittel 1 703 MBq (σ = 123 MBq) in 16,3 Nadeln (σ = 2,5 Nadeln) verwendete. Ein unerfahrener Operateur benötigte für eine Applikation von durchschnittlich 1 469 MBq (σ = 229 MBq) mit 16,8 Nadeln (σ = 2,3 Nadeln) im Mittel 34,8 min (σ = 10,2 min) (Abbildungen 3 und 4). Die beim erfahrenen Arzt gemessene mittlere Strahlenexposition des stärker belaste- ten Fingers betrug 1,31 mSv (σ = 0,54 mSv), jene des Handrückens 0,61 mSv (σ = 0,23 mSv). Die korrespondierenden Werte des unerfahrenen Operateurs lagen bei 2,07 mSv (σ = 0,86 mSv) bzw. 1,05 mSv (σ = 0,53 mSv) (Abbildungen 5, 6a und 6b.Schlussfolgerung:Ohne Berücksichtigung anderer Strahlenexpositionen kann ein erfahrener Arzt pro Jahr etwa 400, ein unerfahrener Arzt etwa 200 Applikationen durchführen, ohne den Dosisgrenzwert von 500 mSv/Jahr zu überschreiten.