Influence of the simultaneous calibration of multiple ring dosimeters on the individual absorbed dose.

Ring dosimeters for personal dosimetry are calibrated in accredited laboratories following ISO 4037-3 guidelines. The simultaneous irradiation of multiple dosimeters would save time, but has to be carefully studied, since the scattering conditions could change and influence the absorbed dose in nearby dosimeters. Monte Carlo simulations using PENELOPE-2014 were performed to explore the need to increase the uncertainty ofHp0.07in the simultaneous irradiation of three and five DXT-RAD 707H-2 (Thermo Scientific) ring dosimeters with beam qualities: N-30, N-80 and N-300. Results show that the absorbed dose in each dosimeter is compatible with each of the others and with the reference simulation (a single dosimeter), with a coverage probability of 95% (k= 2). Comparison with experimental data yielded consistent results with the same coverage probability. Therefore, five ring dosimeters can be simultaneously irradiated with beam qualities ranging, at least, between N-30 and N-300 with a negligible impact on the uncertainty ofHp0.07.

Determination of consensus k Q values for megavoltage photon beams for the update of IAEA TRS-398.

The IAEA is currently coordinating a multi-year project to update the TRS-398 Code of Practice for the dosimetry of external beam radiotherapy based on standards of absorbed dose to water. One major aspect of the project is the determination of new beam quality correction factors, k Q , for megavoltage photon beams consistent with developments in radiotherapy dosimetry and technology since the publication of TRS-398 in 2000. Specifically, all values must be based on, or consistent with, the key data of ICRU Report 90. Data sets obtained from Monte Carlo (MC) calculations by advanced users and measurements at primary standards laboratories have been compiled for 23 cylindrical ionization chamber types, consisting of 725 MC-calculated and 179 experimental data points. These have been used to derive consensus k Q values as a function of the beam quality index TPR20,10 with a combined standard uncertainty of 0.6%. Mean values of MC-derived chamber-specific [Formula: see text] factors for cylindrical and plane-parallel chamber types in 60Co beams have also been obtained with an estimated uncertainty of 0.4%.

Brachytherapy organ dose estimation using Monte Carlo simulations of realistic patient models.

Radiation Therapy Planning Systems (RTPS) currently used in hospitals contain algorithms based on deterministic simplifications that do not properly consider electrons lateral transport in the areas where there are changes of density, and as a result, erroneous dose predictions could be produced. According to this, the present work proposes the use of Monte Carlo method in brachytherapy planning systems, which could affect positively on the radiotherapy treatment planning, since it provides results that are more accurate and takes into account the in homogeneities density variations. This paper presents a Monte Carlo (MC) simulation of a brachytherapy prostate treatment with I-125 seeds, using the latest version of MCNP, v.6.1.1. To that, a 3D model of the anatomy of a real anonymized patient is created from the segmentation of Computed Tomography (CT) images. Treatment over this 3D model is simulated and the dose given to each organ is obtained. These doses are compared with those calculated by deterministic planning system used in hospital demonstrating the effectiveness of MC method in the planning of brachytherapy treatments, because of not only the results precision but also regarding the affordable computing times.

Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects.

The aim of this work is to analyse the scattered radiation produced by the mobile accelerator Mobetron 1000. To do so, detailed Monte Carlo simulations using two different codes, Penelope2008 and Geant4, were performed. Measurements were also done. To quantify the attenuation due to the internal structures, present in the accelerator head, on the scattered radiation produced, some of the main structural shielding in the Mobetron 1000 has been incorporated into the geometry simulation. Results are compared with measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation component due to low energy scattered electrons. This encouraged us to perform additional calculations to separate the role played by this component. Ambient dose equivalent, H*(10), outside of the operating room (OR) has been evaluated using Geant4. H*(10) has been measured inside and outside the OR, being its values compatible with those reported in the literature once the low energy electron component is removed. With respect to the role played by neutrons, estimations of neutron H*(10) using Geant4 together with H*(10) measurements has been performed for the case of the 12 MeV electron beam. The values obtained agree with the experimental values existing in the literature, being much smaller than those registered in conventional accelerators. This study is a useful tool for the clinical user to investigate the radiation protection issues arising with the use of these accelerators in ORs without structural shielding. These results will also enable to better fix the maximum number of treatments that could be performed while insuring adequate radiological protection of workers and public in the hospital.

Correction factors for ionization chamber measurements with the 'Valencia' and 'large field Valencia' brachytherapy applicators.

Treatment of small skin lesions using HDR brachytherapy applicators is a widely used technique. The shielded applicators currently available in clinical practice are based on a tungsten-alloy cup that collimates the source-emitted radiation into a small region, hence protecting nearby tissues. The goal of this manuscript is to evaluate the correction factors required for dose measurements with a plane-parallel ionization chamber typically used in clinical brachytherapy for the 'Valencia' and 'large field Valencia' shielded applicators. Monte Carlo simulations have been performed using the PENELOPE-2014 system to determine the absorbed dose deposited in a water phantom and in the chamber active volume with a Type A uncertainty of the order of 0.1%. The average energies of the photon spectra arriving at the surface of the water phantom differ by approximately 10%, being 384 keV for the 'Valencia' and 343 keV for the 'large field Valencia'. The ionization chamber correction factors have been obtained for both applicators using three methods, their values depending on the applicator being considered. Using a depth-independent global chamber perturbation correction factor and no shift of the effective point of measurement yields depth-dose differences of up to 1% for the 'Valencia' applicator. Calculations using a depth-dependent global perturbation factor, or a shift of the effective point of measurement combined with a constant partial perturbation factor, result in differences of about 0.1% for both applicators. The results emphasize the relevance of carrying out detailed Monte Carlo studies for each shielded brachytherapy applicator and ionization chamber.

Calibration of a thermoluminescent dosimeter worn over lead aprons in fluoroscopy guided procedures.

Fluoroscopy guided interventional procedures provide remarkable benefits to patients. However, medical staff working near the scattered radiation field may be exposed to high cumulative equivalent doses, thus requiring shielding devices such as lead aprons and thyroid collars. In this situation, it remains an acceptable practice to derive equivalent doses to the eye lenses or other unprotected soft tissues with a dosimeter placed above these protective devices. Nevertheless, the radiation backscattered by the lead shield differs from that generated during dosimeter calibration with a water phantom. In this study, a passive personal thermoluminescent dosimeter (TLD) was modelled by means of the Monte Carlo (MC) code Penelope. The results obtained were validated against measurements performed in reference conditions in a secondary standard dosimetry laboratory. Next, the MC model was used to evaluate the backscatter correction factor needed for the case where the dosimeter is worn over a lead shield to estimate the personal equivalent dose H p (0.07) to unprotected soft tissues. For this purpose, the TLD was irradiated over a water slab phantom with a photon beam representative of the result of a fluoroscopy beam scattered by a patient. Incident beam angles of 0° and 60°, and lead thicknesses between the TLD and phantom of 0.25 and 0.5 mm Pb were considered. A backscatter correction factor of 1.23 (independent of lead thickness) was calculated comparing the results with those faced in reference conditions (i.e., without lead shield and with an angular incidence of 0°). The corrected dose algorithm was validated in laboratory conditions with dosimeters irradiated over a thyroid collar and angular incidences of 0°, 40° and 60°, as well as with dosimeters worn by interventional radiologists and cardiologists. The corrected dose algorithm provides a better approach to estimate the equivalent dose to unprotected soft tissues such as eye lenses. Dosimeters that are not shielded from backscatter radiation might underestimate personal equivalent doses when worn over a lead apron and, therefore, should be specifically characterized for this purpose.

VoxelMages: a general-purpose graphical interface for designing geometries and processing DICOM images for PENELOPE.

The design and construction of geometries for Monte Carlo calculations is an error-prone, time-consuming, and complex step in simulations describing particle interactions and transport in the field of medical physics. The software VoxelMages has been developed to help the user in this task. It allows to design complex geometries and to process DICOM image files for simulations with the general-purpose Monte Carlo code PENELOPE in an easy and straightforward way. VoxelMages also allows to import DICOM-RT structure contour information as delivered by a treatment planning system. Its main characteristics, usage and performance benchmarking are described in detail.

Technical Note: Dosimetry of Leipzig and Valencia applicators without the plastic cap.

PURPOSE: High dose rate (HDR) brachytherapy for treatment of small skin lesions using the Leipzig and Valencia applicators is a widely used technique. These applicators are equipped with an attachable plastic cap to be placed during fraction delivery to ensure electronic equilibrium and to prevent secondary electrons from reaching the skin surface. The purpose of this study is to report on the dosimetric impact of the cap being absent during HDR fraction delivery, which has not been explored previously in the literature. METHODS: geant4 Monte Carlo simulations (version 10.0) have been performed for the Leipzig and Valencia applicators with and without the plastic cap. In order to validate the Monte Carlo simulations, experimental measurements using radiochromic films have been done. RESULTS: Dose absorbed within 1 mm of the skin surface increases by a factor of 1500% for the Leipzig applicators and of 180% for the Valencia applicators. Deeper than 1 mm, the overdosage flattens up to a 10% increase. CONCLUSIONS: Differences of treating with or without the plastic cap are significant. Users must check always that the plastic cap is in place before any treatment in order to avoid overdosage of the skin. Prior to skin HDR fraction delivery, the timeout checklist should include verification of the cap placement.

Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions.

PURPOSE: The aims of this study were (i) to design a new high-dose-rate (HDR) brachytherapy applicator for treating surface lesions with planning target volumes larger than 3 cm in diameter and up to 5 cm in size, using the microSelectron-HDR or Flexitron afterloader (Elekta Brachytherapy) with a (192)Ir source; (ii) to calculate by means of the Monte Carlo (MC) method the dose distribution for the new applicator when it is placed against a water phantom; and (iii) to validate experimentally the dose distributions in water. METHODS: The penelope2008 MC code was used to optimize dwell positions and dwell times. Next, the dose distribution in a water phantom and the leakage dose distribution around the applicator were calculated. Finally, MC data were validated experimentally for a (192)Ir mHDR-v2 source by measuring (i) dose distributions with radiochromic EBT3 films (ISP); (ii) percentage depth-dose (PDD) curve with the parallel-plate ionization chamber Advanced Markus (PTW); and (iii) absolute dose rate with EBT3 films and the PinPoint T31016 (PTW) ionization chamber. RESULTS: The new applicator is made of tungsten alloy (Densimet) and consists of a set of interchangeable collimators. Three catheters are used to allocate the source at prefixed dwell positions with preset weights to produce a homogenous dose distribution at the typical prescription depth of 3 mm in water. The same plan is used for all available collimators. PDD, absolute dose rate per unit of air kerma strength, and off-axis profiles in a cylindrical water phantom are reported. These data can be used for treatment planning. Leakage around the applicator was also scored. The dose distributions, PDD, and absolute dose rate calculated agree within experimental uncertainties with the doses measured: differences of MC data with chamber measurements are up to 0.8% and with radiochromic films are up to 3.5%. CONCLUSIONS: The new applicator and the dosimetric data provided here will be a valuable tool in clinical practice, making treatment of large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal.

Evaluation of lens absorbed dose with Cone Beam IGRT procedures.

The purpose of this work is to evaluate the absorbed dose to the eye lenses due to the cone beam computed tomography (CBCT) system used to accurately position the patient during head-and-neck image guided procedures. The on-board imaging (OBI) systems (v.1.5) of Clinac iX and TrueBeam (Varian) accelerators were used to evaluate the imparted dose to the eye lenses and some additional points of the head. All CBCT scans were acquired with the Standard-Dose Head protocol from Varian. Doses were measured using thermoluminescence dosimeters (TLDs) placed in an anthropomorphic phantom. TLDs were calibrated at the beam quality used to reduce their energy dependence. Average dose to the lens due to the OBI systems of the Clinac iX and the TrueBeam were 0.71 ± 0.07 mGy/CBCT and 0.70 ± 0.08 mGy/CBCT, respectively. The extra absorbed dose received by the eye lenses due to one CBCT acquisition with the studied protocol is far below the 500 mGy threshold established by ICRP for cataract formation (ICRP 2011 Statement on Tissue Reactions). However, the incremental effect of several CBCT acquisitions during the whole treatment should be taken into account.

Comparison and uncertainty evaluation of different calibration protocols and ionization chambers for low-energy surface brachytherapy dosimetry.

PURPOSE: A surface electronic brachytherapy (EBT) device is in fact an x-ray source collimated with specific applicators. Low-energy (<100 kVp) x-ray beam dosimetry faces several challenges that need to be addressed. A number of calibration protocols have been published for x-ray beam dosimetry. The media in which measurements are performed are the fundamental difference between them. The aim of this study was to evaluate the surface dose rate of a low-energy x-ray source with small field applicators using different calibration standards and different small-volume ionization chambers, comparing the values and uncertainties of each methodology. METHODS: The surface dose rate of the EBT unit Esteya (Elekta Brachytherapy, The Netherlands), a 69.5 kVp x-ray source with applicators of 10, 15, 20, 25, and 30 mm diameter, was evaluated using the AAPM TG-61 (based on air kerma) and International Atomic Energy Agency (IAEA) TRS-398 (based on absorbed dose to water) dosimetry protocols for low-energy photon beams. A plane parallel T34013 ionization chamber (PTW Freiburg, Germany) calibrated in terms of both absorbed dose to water and air kerma was used to compare the two dosimetry protocols. Another PTW chamber of the same model was used to evaluate the reproducibility between these chambers. Measurements were also performed with two different Exradin A20 (Standard Imaging, Inc., Middleton, WI) chambers calibrated in terms of air kerma. RESULTS: Differences between surface dose rates measured in air and in water using the T34013 chamber range from 1.6% to 3.3%. No field size dependence has been observed. Differences are below 3.7% when measurements with the A20 and the T34013 chambers calibrated in air are compared. Estimated uncertainty (with coverage factor k = 1) for the T34013 chamber calibrated in water is 2.2%-2.4%, whereas it increases to 2.5% and 2.7% for the A20 and T34013 chambers calibrated in air, respectively. The output factors, measured with the PTW chambers, differ by less than 1.1% for any applicator size when compared to the output factors that were measured with the A20 chamber. CONCLUSIONS: Measurements using both dosimetric protocols are consistent, once the overall uncertainties are considered. There is also consistency between measurements performed with both chambers calibrated in air. Both the T34013 and A20 chambers have negligible stem effect. Any x-ray surface brachytherapy system, including Esteya, can be characterized using either one of these calibration protocols and ionization chambers. Having less correction factors, lower uncertainty, and based on measurements, performed in closer to clinical conditions, the TRS-398 protocol seems to be the preferred option.

Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities.

In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for (192)Ir and (60)Co HDR applications to account for several different bunker layouts.For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by (192)Ir and (60)Co will reduce the lead thickness by a factor of five for (192)Ir and ten for (60)Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers.The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.

Monte Carlo dosimetric study of the medium dose rate CSM40 source.

The (137)Cs medium dose rate (MDR) CSM40 source model (Eckert & Ziegler BEBIG, Germany) is in clinical use but no dosimetric dataset has been published. This study aims to obtain dosimetric data for the CSM40 source for its use in clinical practice as required by the American Association of Physicists in Medicine (AAPM) and the European Society for Radiotherapy and Oncology (ESTRO). Penelope2008 and Geant4 Monte Carlo codes were used to characterize this source dosimetrically. It was located in an unbounded water phantom with composition and mass density as recommended by AAPM and ESTRO. Due to the low photon energies of (137)Cs, absorbed dose was approximated by collisional kerma. Additional simulations were performed to obtain the air-kerma strength, sK. Mass-energy absorption coefficients in water and air were consistently derived and used to calculate collisional kerma. Results performed with both radiation transport codes showed agreement typically within 0.05%. Dose rate constant, radial dose function and anisotropy function are provided for the CSM40 and compared with published data for other commercially available (137)Cs sources. An uncertainty analysis has been performed. The data provided by this study can be used as input data and verification in the treatment planning systems.

Transposition of iliac vessels in implantation of right living donor kidneys.

BACKGROUND: The rate of right laparoscopic living-donor nephrectomy (RLLDN) is low among kidney transplantations due to the short renal vein and presumed higher risk of thrombosis. Our objective was to describe a surgical technique to compensate for the shorter veins of these grafts. METHODS: Between January 2004 and July 2010, we prospectively collected data from all transplantations using RLLDN-harvested kidneys at our center. Recipient iliac vein transposition was performed in all patients. We reviewed the indications, surgical techniques, and postoperative courses. RESULTS: The 43 included cases showed a 2.1 +/- 0.6 cm, average length of the right renal vein as measured on abdominal computed tomography (CT). The mean extraction and implantation times were 109 +/- 33 and 124 +/- 31 minutes, respectively; the mean warm ischemia time was 151 +/- 29 seconds. Two recipients required postsurgical blood transfusions. In 97.6% of cases, there was immediate urine flow. Postoperative echo-Doppler revealed good arterial and venous flows in all patients. No venous thromboses were detected. The recipients' average hospital stay was 8 +/- 5 days. With a mean follow-up of 57 months, 86% of recipients maintain a glomerular filtration rate (GFR) >50 mL/min and creatinine levels <1.5 mg/dL. CONCLUSIONS: Transposition of the recipient iliac vein during implantation is a good technical solution to compensate for the short length of the right renal vein. The use of iliac vein transposition allowed us to perform safe implants of RLLDN-harvested kidneys with good short-term and long-term results.

SU-E-T-316: New Design of the Valencia Applicators to Reduce Radiation Leakage.

PURPOSE: The Valencia applicators are designed to treat skin lesions with the microSelectron-HDR afterloader. Although the radiation is highly directed to the treatment area, radiation might leak through the backside of the applicator. Recently, the manufacturer has introduced a new applicator design to reduce such radiation leakage. This new design consists mainly in the addition of about 4 mm of tungsten in the backside of the applicator making it thicker. The purpose of this study is to evaluate by means of the Monte Carlo method the radiation leakage of this new design and to evaluate whether this modification affects the dose rate distributions in the treatment area. METHODS: The complete geometry of the new applicators has been introduced in the Monte Carlo code GEANT4. The applicators have been located on the surface of a cylindrical water phantom following a methodology similar to the used in the original study of the Valencia applicators by Granero et al [Med.Phys 2008;35:495-503]. Kerma in the water phantom and kerma in air outside the phantom have been evaluated to estimate the radiation leakage of the new designed Valencia applicators. RESULTS: The Monte Carlo simulations of the new applicators show that the radiation leakage has been reduced significantly from the previous design. The largest radiation leakage of this design is now about 30% of the dose at the prescription point and about 10% at 1 cm from the backside of the applicators. The dose rate distributions in the area of treatment have not changed. CONCLUSIONS: In this study the radiation leakage of the new design of the Valencia applicators has been obtained. The radiation leakages have been largely reduced from the previous design without compromising dose rate distributions in the treatment area.

SU-E-T-467: Monte Carlo Dosimetric Study of the New Flexisource Co-60 High Dose Rate Source.

PURPOSE: Recently, a new HDR 60Co brachytherapy source, Flexisource Co-60, has been developed (Nucletron B.V.). This study aims to obtain quality dosimetric data for this source for its use in clinical practice as required by AAPM and ESTRO. METHODS: Penelope2008 and GEANT4 Monte Carlo codes were used to dosimetrically characterize this source. Water composition and mass density was that recommended by AAPM. Due to the high energy of the 60Co, dose for small distances cannot be approximated by collisional kerma. Therefore, we have considered absorbed dose to water for r<0.75 cm and collisional kerma from 0.75 0.8 cm and up to 2% closer to the source. Using Penelope2008 and GEANT4, an average of Î> = 1.085±0.003 cGy/(h U) (with k = 1, Type A uncertainties) was obtained. Dose rate constant, radial dose function and anisotropy functions for the Flexisource Co-60 are compared with published data for other Co-60 sources. CONCLUSIONS: Dosimetric data are provided for the new Flexisource Co-60 source not studied previously in the literature. Using the data provided by this study in the treatment planning systems, it can be used in clinical practice. This project has been funded by Nucletron BV.

Sangrado diferido después de nefrectomía parcial. Manejo mediante embolización selectiva / Delayed Bleeding after Partial Nephrectomy. Management with Selective Embolization

Introducción: El sangrado después de una nefrectomía parcial es una complicación con posibles consecuencias graves. Puede ser inmediato o diferido y su incidencia es baja. La causa más frecuente del sangrado diferido es el pseudoaneurisma arterial. La embolización supraselectiva vascular es una opción terapéutica posible que ha demostrado buenos resultados. Objetivo: Evaluar la evolución y el tratamiento del sangrado diferido en nuestra serie de pacientes con nefrectomías parciales. Material y métodos: Realizamos un estudio retrospectivo de nuestra base de datos de nefrectomías parciales. Identificamos los pacientes que presentaron sangrado diferido (después del alta). Se revisó la historia clínica, analizando datos sobre la presentación, el diagnóstico, el tratamiento y la evolución de los pacientes. Resultados: De nuestra serie de nefrectomías parciales tres pacientes presentaron sangrado diferido (1,3%). La clínica se inició después de 17 a 25 días de la cirugía por la aparición de hematuria o dolor lumbar. El diagnóstico se realizó mediante ecografía, TAC abdominal y angiografía renal. En todos los pacientes se diagnosticó un pseudoaneurisma arterial complicado, siendo sometidos a cateterismo arterial renal con embolización selectiva del mismo. La evolución fue correcta en todos los pacientes con control inmediato del sangrado. Documentamos un seguimiento posterior favorable de 61 a 92 meses. Conclusiones: La embolización selectiva vascular es el tratamiento de elección del pseudoaneurisma renal sintomático después de nefrectomía parcial en el paciente hemodinámicamente estable (AU)

Introduction: Bleeding after partial nephrectomy can be immediate or delayed and may have severe consequences. The incidence of this complication is low. The most frequent cause of delayed bleeding is arterial pseudoaneurysm. Superselective embolization is a feasible therapeutic option that has shown good results. Objective: To evaluate treatment and outcomes of delayed bleeding in our series of patients with partial nephrectomy. Material and methods: We performed a retrospective study of our database of partial nephrectomies. Patients who developed delayed bleeding (after discharge) were identified. Clinical histories were reviewed and data on presentation, diagnosis, treatment and outcomes were analyzed. Results: Among our series of patients undergoing partial nephrectomy, three developed delayed bleeding (1.3%). Symptom onset occurred 17 to 25 days after surgery and consisted of hematuria or lumbar pain. Diagnosis was provided through ultrasound, abdominal computed tomography and renal angiography. In all three patients, a complicated pseudoaneurysm was diagnosed and all patients underwent renal artery catheterization with selective renal artery embolization. In all patients, immediate control of bleeding was achieved. Outcome after a follow-up of 61 to 92 months was favorable. Conclusions: Selective vascular embolization is the treatment of choice of renal pseudoaneurysm after partial nephrectomy in hemodynamically stable patients (AU)

[Delayed bleeding after partial nephrectomy. Management with selective embolization]. / Sangrado diferido después de nefrectomía parcial. Manejo mediante embolización selectiva.

INTRODUCTION: Bleeding after partial nephrectomy can be immediate or delayed and may have severe consequences. The incidence of this complication is low. The most frequent cause of delayed bleeding is arterial pseudoaneurysm. Superselective embolization is a feasible therapeutic option that has shown good results. OBJECTIVE: To evaluate treatment and outcomes of delayed bleeding in our series of patients with partial nephrectomy. MATERIAL AND METHODS: We performed a retrospective study of our database of partial nephrectomies. Patients who developed delayed bleeding (after discharge) were identified. Clinical histories were reviewed and data on presentation, diagnosis, treatment and outcomes were analyzed. RESULTS: Among our series of patients undergoing partial nephrectomy, three developed delayed bleeding (1.3%). Symptom onset occurred 17 to 25 days after surgery and consisted of hematuria or lumbar pain. Diagnosis was provided through ultrasound, abdominal computed tomography and renal angiography. In all three patients, a complicated pseudoaneurysm was diagnosed and all patients underwent renal artery catheterization with selective renal artery embolization. In all patients, immediate control of bleeding was achieved. Outcome after a follow-up of 61 to 92 months was favorable. CONCLUSIONS: Selective vascular embolization is the treatment of choice of renal pseudoaneurysm after partial nephrectomy in hemodynamically stable patients.

Charmonium spectroscopy above thresholds.

We present a systematic and self-consistent analysis of four-quark charmonium states and applied it to study compact four-quark systems and meson-meson molecules. Our results are robust and should serve to clarify the situation of charmonium spectroscopy above the threshold production of charmed mesons.