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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 192Ir 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 penelope2008MC 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 192Ir 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.

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.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.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%.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.

Ir-192 wires have been used in low-dose-rate brachytherapy for many years. Commercially available treatment planning systems approximate the dose rate distribution of the straight or curved wires applying the superposition principle using one of the following methods: (i) The wire is modeled as a set of point sources, (ii) the wire is modeled as a set of small straight segment wires, (iii) the values of the parameters and functions of the American Association of Physicists in Medicine (AAPM) Task Group 43 protocol are obtained for wire lengths between 3 and 7 cm assuming some simplifications. The dose rate distributions obtained using these methods for linear wires of different lengths and U-shaped wires present significant deviations compared to those obtained by Monte Carlo. In the present study we propose a new method to model 192Ir wires of any length and shape, named the Two Lengths based Segmented method. This method uses the formalism stated in the AAPM Task Group 43 protocol for two straight wires only, 0.5 and 1 cm, to obtain the dose rate distribution around wires of any length (down to 0.3 cm and up to 10 cm) improving on the results of the aforementioned ones. This method can easily be applied to dose calculations around other wires, such as Pd-103 ones.

The purposes of this study are: (i) to design field flattening filters for the Leipzig applicators of 2 and 3 cm of inner diameter with the source traveling parallel to the applicator contact surface, which are accessories of the microSelectron-HDR afterloader (Nucletron, Veenendaal, The Netherlands). These filters, made of tungsten, aim to flatten the heterogeneous dose distribution obtained with the Leipzig applicators. (ii) To estimate the dose rate distributions for these Leipzig+filter applicators by means of the Monte Carlo (MC) method. (iii) To experimentally verify these distributions for prototypes of these new applicators, and (iv) to obtain the correspondence factors to measure the output of the applicators by the user using an insert into a well chamber. The MC GEANT4 code has been used to design the filters and to obtain the dose rate distributions in liquid water for the two Leipzig+filter applicators. In order to validate this specific application and to guarantee that realistic source-applicator geometry has been considered, an experimental verification procedure was implemented in this study, in accordance with the updated recommendations of the American Association of Physicists in Medicine Task Group No. 43 U1 Report. Thermoluminescent dosimeters, radiochromic film, and a pin-point ionization chamber in a plastic [polymethylmethacrylate (PMMA)] phantom were used to verify the MC results for the two applicators of a microSelectron-HDR afterloader with the mHDR-v2 source. To verify the output of the Leipzig +filter applicators, correspondence factors were deduced for the well chambers HDR100-plus (Standard Imaging, Inc., Middleton, WI) and TM33004 (PTW, Freiburg, Germany) using a specific insert for both applicators. The doses measured in the PMMA phantom agree within experimental uncertainties with the dose obtained by the MC calculations. Percentage depth dose and off-axis profiles were obtained normalized at a depth of 3 mm along the central applicator axis in a cylindrical 20 x 20 cm water phantom. A table of output factors, normalized to 1 U of source air kerma strength at this depth, is presented. Correspondence factors were obtained for the two well chambers considered. The matrix data obtained in the MC simulation with a grid separation of 0.5 mm has been used to build a data set in a convenient format to model these distributions for routine use with a brachytherapy treatment planning system.

The H-type Leipzig applicators are accessories of the microSelectron-HDR system (Nucletron, Veenendaal, The Netherlands) for treatment of superficial malignancies. Recently, the dose rate distributions in liquid water for the whole set of applicators using both source models available for the microSelectron-HDR afterloaders have been obtained by means of the experimentally validated Monte Carlo (MC) code GEANT4. Also an output table (cGy/hU) at 3 mm depth on the applicator central axis was provided. The output verification of these applicators by the user, prior to their clinical use, present practical problems: small detectors such as thermoluminescent dosimeters or parallel-plate ionization chambers are not easily used for verification in a clinical environment as they require a rigid setup with the Leipzig applicator and a phantom. In contrast, well-type ionization chambers are readily available in radiotherapy departments. This study presents a technique based on the HDR1000Plus well chamber (Standar Imaging) measurements with a special insert, which allows the output verification of the H-type Leipzig applicators on a routine basis. This technique defines correspondence factors (CF) between the in water dose rate output of the Leipzig applicators (cGy/hU) obtained with MC and the reading on the well chamber with the special insert, normalized to themore » HDR calibration factor with the HDR insert and to the source strength. To commission the applicators (with the well chamber and the special insert used), the physicist should check if the CF value agrees with its tabulated values presented in this work. If the differences are within 5% the tabulated output values can be used in clinical dosimetry. This technique allows the output validation of the Leipzig applicators with a well chamber widely used for HDR Ir-192 source strength measurements. It can easily be adapted to other types of well chambers for HDR source output verification.« less

Geographical, Historical and Archaeological Perspectives on the Production and Transmission of LandscapesLandscape Biographies€ 98,99ISBN:9789048517800Verschijningsdatum:07-05-2015Leverbaar: DirectUitvoering: PDFAantal paginas:336Redacteur:Jan Kolen, Rita Hermans, Hans RenesOok verkrijgbaar als:HardbackSerie:Landscape and Heritage StudiesPrint Flyeradd iconBestellenLandscape BiographiesLandscape Biographies explores the long and complex histories of landscapes from personal and social perspectives. As an essential part of human life-worlds, landscapes have the potential to absorb something of people's lives, works, and thoughts. But landscapes also shape their own life-histories at different timescales, transcending human life-cycles and generating their own temporalities and rhythms. It comes as no surprise, therefore, that the co-scripting of landscapes and people figures prominently in the (auto-)biographical works of writers and attracts the interest of geographers, archaeologists, historians, and anthropologists. This has even resulted in a new genre in landscape research, rapidly gaining in popularity, under the heading of 'landscape biography'. In Landscape Biographies, twenty geographers, archaeologists, historians, and anthropologists investigate the diverse ways in which landscapes and monuments have been constructed, transmitted, and transformed from prehistory up to the present, from Manhattan to Shanghai, from Iceland to Portugal, and from England to Estonia.

SamenvattingEr is vermoedelijk geen onderwerp in de geschiedenis waarover meer is geschreven dan de Republiek der Verenigde Nederlanden en de Hollandse Gouden Eeuw. Toch toont dit boek een heel ander land dan de vertrouwde koopmansnatie met haar steedse allure, propere huiselijkheid en idyllische landschapjes. Rob van der Laarse kantelt dit beeld door te kijken naar de manier waarop aristocratische families elkaar in alle gewesten beconcurreerden met monumentale huizen, voorname heerlijkheden en luisterrijke kunstcollecties. Op zoek naar de 'makers' van dit land raken we verzeild in een wereld van adel, hof en buitenplaats. De Nederlandse aanzienlijkheid werd beheerst door virtus, smaak en distinctie, ofwel door feodaliteit en classicisme. Arcadiërs van de Republiek is daarmee ook een duiding van een allang vergeten droom: het ideaal van een herboren Rome. In contrast met de vrijwel permanente staat van oorlog waarin de Republiek verkeerde, veranderde dit verlangen naar Arcadië het land in de mooiste tuin van Europa. Het boek dat onze kijk op de geschiedenis van de Republiek voorgoed zal veranderen

Auschwitz staat symbool voor heel de Europese erfenis van "de eeuw van de kampen". Uit de brokstukken hiervan dient de Europeaan een nieuwe toekomst te fabriceren, betoogt prof. dr. Robert van der Laarse. De auteur is hoofddocent cultureel erfgoed aan de Universiteit van Amsterdam. Dit artikel is een bewerking van de oratie die hij gisteren uitsprak bij de aanvaarding van het ambt van bijzonder hoogleraar erfgoed van de oorlog aan de Vrije Universiteit.

Acknowledging the paradigmatic impact of new digital techniques, this contribution questions the depoliticized conceptualization of landscape in modern landscape visualizations from a theoretical and historical perspective. Long after the earlier periods of formal gardening and landscaping, the present-day heritage focus on landscapes is looked upon as the real shift in the perception of landscapes, representing an appropriation by tourists and other groups of people without any historical connection to their history and nature.

Het gaat om een verzoek van en advies aan: Staatssecretaris van Volksgezondheid, Welzijn en Sport, mevr. Drs. M.L.L.E. Veldhuijzen van Zanten-Hyllner, kenmerk brief DMO/OHW-U-3086756, Directoraat Generaal Langdurige Zorg, Directie Maatschappelijke Ondersteuning, Afdeling OHW II (contactpersoon dhr. B. Bijl, email b.bijl@minvws.nl) adres Ministerie van VWS Parnassusplein 5 2511 VX Den Haag

In het voormalige doorvoerkamp Westerbork graven archeologen sindsdeze week naar sporen van het dagelijks leven. ‘De vraag dient zich aanvan wie Westerbork eigenlijk is.’ Door Ana van Es en Maarten Keulemans.

In contrast to other European countries 19 th century-court architecture in the Netherlands has not left a strong imprint on public memory. Just as most historical cities, most palaces in the Netherlands were restored in 17 th century Dutch Classicist Style, suggesting that after the Golden Age nothing happened. This article shows that such an impression is misleading. Focusing on the new monarchy of the Restoration era (1813-1848) it becomes clear that the first Orange kings William I and II started impressive building campaigns in both the Southern and Northern Netherlands, comparable to those of the 17 th century. Prince Frederick Henry and the Anglo-Dutch King-Stadtholder William III. Remarkably, in the early 19 th century the most magnificent palaces in neoclassicist style - except for Soestdijk - were built by the prince royal in and around Brussels. Nevertheless, the Belgian revolution of 1830 ended the role of the Orange dynasty in Brussels, after which royal and princely palaces, summer houses, and art collections were appropriated by the new Belgian monarchy. Although most of them are still in use, their origin has been completely forgotten. Strangely, this also happened to King William II's new palaces of the 1830s and 1840s in Windsor Tudor Style. This so-called William II Gothic was very popular at the time, but from the 1870s no longer fashionable in Protestant court circles after having been appropriated by Roman-Catholic architects for church building. The King was influenced by the memory of his Oxford college days, as can still be seen in the Gothic Hall of his Kneuterdijk Palace in The Hague, designed by himself as a Painting Gallery modelled after the hall of Christ Church College. A much larger project, however, the so-called Zorgvliet Palace at his huge private domain Williams Park between his The Hague palaces and the beach of Scheveningen, had a different origin. With the help of the English architect Ashton, the King made plans for a residential palace that would surpass his lost Brussels palaces and compete with the royal 'court scapes' of Versailles, Windsor and Potsdam. Connected by kinship and marriage to the Hohenzollern, William II shared the Prussian longing for castellated palaces as developed by Schinkel for his sisters, brothers and nephews in Germany. Nevertheless, palace building was stopped abruptly after the liberal revolution of 1848, when the Orange court lost its political power and almost went bankrupt because of overspending. After William II's death in 1849 the court had to sell its magnificent art collection, and William III - who disliked Roman Catholics and the Gothic Revival - sold most of his father's palaces. For almost three decades palaces in the Netherlands were only built by the king's relatives, such as his uncle Prince Frederick who owned the famous estate Muskau at the German-Polish Border as well as the Dutch estate The Horsten near The Hague. With the help of the Prussian architect Wentzel and the Muskauer landscape designer Petzold, Frederick introduced the Schinkel Style in the Netherlands. Nevertheless, enriched by the inheritance of his brother Prince Henry grand duke of Luxembourg, William III started a last royal building campaign in the 1870s, supporting the Baroque Revival of his favourite Eberson. Just as in the case of his father, his new plan for a residential castle at Zorgvliet failed, however, and after the king's death in 1890 the royal domains in and around The Hague were sold to the city government and some private investors. Ironically, near Lord Portland's former summer house Zorgvliet or Catshuis (used today as the official residence of the Prime Minister), the Carnegy Foundation built the famous Peace Palace in French Neo-Renaissance Style in the early 20 th century, which could be seen as the final outcome of the royal dream of a Williams Park Court., Bulletin KNOB, Bulletin KNOB 109 (2010) 5

The separation of the total scatter correction factor Sc, p in a collimator scatter component, Sc, and a phantom scatter component, Sp, has proven to be an useful concept in megavoltage photon beam dose calculations in situations which differ from the standard treatment geometry. A clinically applicable method to determine Sc is described. Measurements are carried out with an ionization chamber, placed at a depth beyond the range of contaminant electrons, in a narrow cylindrical polystyrene phantom with a diameter of 4 cm of which the axis coincides with the beam axis. Sc, p is measured in a full-scatter phantom and Sp can be derived from Sc, p and Sc. In order to obtain a reliable separation, i.e. excluding the influence of contaminant electrons, measurements of Sc, p have been carried out at depths of 5 cm for photon beams with a quality index (QI) up to and including 0.75 and a depth of 10 cm with QI larger than 0.75. These depths are in accordance with recommendations given in recent dosimetry protocols. The consistency of the method was checked by comparing calculated and measured values of Sc, p for a set of blocked fields for a range of photon beam energies from 60Co up to 25 MV showing a maximum deviation of 2%. The method can easily be implemented in existing procedures for the calculation of the number of monitor units to deliver a specified dose to a target volume.

Ir-192 wires have been used in low-dose-rate brachytherapy for many years. Commercially available treatment planning systems approximate the dose rate distribution of the straight or curved wires applying the superposition principle using one of the following methods: (i) The wire is modeled as a set of point sources, (ii) the wire is modeled as a set of small straight segment wires, (iii) the values of the parameters and functions of the American Association of Physicists in Medicine (AAPM) Task Group 43 protocol are obtained for wire lengths between 3 and 7 cm assuming some simplifications. The dose rate distributions obtained using these methods for linear wires of different lengths and U-shaped wires present significant deviations compared to those obtained by Monte Carlo. In the present study we propose a new method to model 192Ir wires of any length and shape, named the Two Lengths based Segmented method. This method uses the formalism stated in the AAPM Task Group 43 protocol for two straight wires only, 0.5 and 1 cm, to obtain the dose rate distribution around wires of any length (down to 0.3 cm and up to 10 cm) improving on the results of the aforementioned ones. This method can easily be applied to dose calculations around other wires, such as Pd-103 ones.

The purposes of this study are: (i) to design field flattening filters for the Leipzig applicators of 2 and 3 cm of inner diameter with the source traveling parallel to the applicator contact surface, which are accessories of the microSelectron-HDR afterloader (Nucletron, Veenendaal, The Netherlands). These filters, made of tungsten, aim to flatten the heterogeneous dose distribution obtained with the Leipzig applicators. (ii) To estimate the dose rate distributions for these Leipzig+filter applicators by means of the Monte Carlo (MC) method. (iii) To experimentally verify these distributions for prototypes of these new applicators, and (iv) to obtain the correspondence factors to measure the output of the applicators by the user using an insert into a well chamber. The MC GEANT4 code has been used to design the filters and to obtain the dose rate distributions in liquid water for the two Leipzig+filter applicators. In order to validate this specific application and to guarantee that realistic source-applicator geometry has been considered, an experimental verification procedure was implemented in this study, in accordance with the updated recommendations of the American Association of Physicists in Medicine Task Group No. 43 U1 Report. Thermoluminescent dosimeters, radiochromic film, and a pin-point ionization chamber in a plastic [polymethylmethacrylate (PMMA)] phantom were used to verify the MC results for the two applicators of a microSelectron-HDR afterloader with the mHDR-v2 source. To verify the output of the Leipzig +filter applicators, correspondence factors were deduced for the well chambers HDR100-plus (Standard Imaging, Inc., Middleton, WI) and TM33004 (PTW, Freiburg, Germany) using a specific insert for both applicators. The doses measured in the PMMA phantom agree within experimental uncertainties with the dose obtained by the MC calculations. Percentage depth dose and off-axis profiles were obtained normalized at a depth of 3 mm along the central applicator axis in a cylindrical 20 x 20 cm water phantom. A table of output factors, normalized to 1 U of source air kerma strength at this depth, is presented. Correspondence factors were obtained for the two well chambers considered. The matrix data obtained in the MC simulation with a grid separation of 0.5 mm has been used to build a data set in a convenient format to model these distributions for routine use with a brachytherapy treatment planning system.

Purpose: Estimation of deviations between planned and delivered dose in Pulsed Doserate (PDR) brachytherapy for prostate cancer. Methods: A boost of 28.8 Gy is given with PDR brachytherapy in addition to 46 Gy delivered with External Beam RT. Brachytherapy is given in 24 pulses of 120 cGy, with an interpulse period time of 2.0 hours, resulting in a treatment time of over 46 hours. For 31 patients, additional CT‐scans were made apart from the Treatment Planning CT, i.e., one at 24 hours after start of PDR treatment and one shortly before finishing PDR treatment. On the second and third CT, the brachytherapy catheters were newly reconstructed and the treating physician delineated the PTV and organs at risk. Dwell positions and dwell times as used for the original Treatment Plan were imported into the newly reconstructed catheters and the dose distribution was recalculated. Plan comparison parameters were prostate V100 and D90 and rectum and bladder D2cc. Results: Averaged over 3 CT scans and all patients, the prostate V100 decreased 1.2% and D90 decreased 2.7%. For rectum, D2cc was within the tolerance dose (96 cGy/pulse) for all patients on the planning CT, but exceeded the tolerance dose on scan #2 in 7/31 patients with maximally 46% and in scan #3 in 5/25 patients with maximally 29%. Also for bladder D2cc was within the tolerance dose (120 cGy/pulse) for all patients on the planning CT. Here, the tolerance dose was exceeded on scan #2 in 2/31 patients with maximally 14% and in scan #3 in 3/25 patients with maximally 28%. Conclusions: In PDR prostate brachytherapy the relatively long treatment time has no clinically relevant deteriorating effect on the dosimetric quality of the treatment. PTV dose hardly deviates from planned dose, while OAR tolerance doses are rarely exceeded and only in small volumes. © 2012, American Association of Physicists in Medicine. All rights reserved.