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Murray L, Mason J, Henry AM, Hoskin P, Siebert FA, Venselaar J, Bownes P. Modelling second malignancy risks from low dose rate and high dose rate brachytherapy as monotherapy for localised prostate cancer. Radiother Oncol 2016; 120:293-9. [PMID: 27370205 DOI: 10.1016/j.radonc.2016.05.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND AND PURPOSE To estimate the risks of radiation-induced rectal and bladder cancers following low dose rate (LDR) and high dose rate (HDR) brachytherapy as monotherapy for localised prostate cancer and compare to external beam radiotherapy techniques. MATERIALS AND METHODS LDR and HDR brachytherapy monotherapy plans were generated for three prostate CT datasets. Second cancer risks were assessed using Schneider's concept of organ equivalent dose. LDR risks were assessed according to a mechanistic model and a bell-shaped model. HDR risks were assessed according to a bell-shaped model. Relative risks and excess absolute risks were estimated and compared to external beam techniques. RESULTS Excess absolute risks of second rectal or bladder cancer were low for both LDR (irrespective of the model used for calculation) and HDR techniques. Average excess absolute risks of rectal cancer for LDR brachytherapy according to the mechanistic model were 0.71 per 10,000 person-years (PY) and 0.84 per 10,000 PY respectively, and according to the bell-shaped model, were 0.47 and 0.78 per 10,000 PY respectively. For HDR, the average excess absolute risks for second rectal and bladder cancers were 0.74 and 1.62 per 10,000 PY respectively. The absolute differences between techniques were very low and clinically irrelevant. Compared to external beam prostate radiotherapy techniques, LDR and HDR brachytherapy resulted in the lowest risks of second rectal and bladder cancer. CONCLUSIONS This study shows both LDR and HDR brachytherapy monotherapy result in low estimated risks of radiation-induced rectal and bladder cancer. LDR resulted in lower bladder cancer risks than HDR, and lower or similar risks of rectal cancer. In absolute terms these differences between techniques were very small. Compared to external beam techniques, second rectal and bladder cancer risks were lowest for brachytherapy.
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Affiliation(s)
- Louise Murray
- Departments of Radiotherapy and Medical Physics, St James's Institute of Oncology, UK; University of Leeds, UK
| | - Joshua Mason
- Departments of Radiotherapy and Medical Physics, St James's Institute of Oncology, UK
| | - Ann M Henry
- Departments of Radiotherapy and Medical Physics, St James's Institute of Oncology, UK; University of Leeds, UK.
| | | | | | | | - Peter Bownes
- Departments of Radiotherapy and Medical Physics, St James's Institute of Oncology, UK
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Murray L, Henry A, Hoskin P, Siebert FA, Venselaar J. Second primary cancers after radiation for prostate cancer: a systematic review of the clinical data and impact of treatment technique. Radiother Oncol 2014; 110:213-28. [PMID: 24485765 PMCID: PMC3988985 DOI: 10.1016/j.radonc.2013.12.012] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 12/18/2013] [Accepted: 12/25/2013] [Indexed: 02/07/2023]
Abstract
The development of a radiation induced second primary cancer (SPC) is one the most serious long term consequences of successful cancer treatment. This review aims to evaluate SPC in prostate cancer (PCa) patients treated with radiotherapy, and assess whether radiation technique influences SPC. A systematic review of the literature was performed to identify studies examining SPC in irradiated PCa patients. This identified 19 registry publications, 21 institutional series and 7 other studies. There is marked heterogeneity in published studies. An increased risk of radiation-induced SPC has been identified in several studies, particularly those with longer durations of follow-up. The risk of radiation-induced SPC appears small, in the range of 1 in 220 to 1 in 290 over all durations of follow-up, and may increase to 1 in 70 for patients followed up for more than 10 years, based on studies which include patients treated with older radiation techniques (i.e. non-conformal, large field). To date there are insufficient clinical data to draw firm conclusions about the impact of more modern techniques such as IMRT and brachytherapy on SPC risk, although limited evidence is encouraging. In conclusion, despite heterogeneity between studies, an increased risk of SPC following radiation for PCa has been identified in several studies, and this risk appears to increase over time. This must be borne in mind when considering which patients to irradiate and which techniques to employ.
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Affiliation(s)
| | - Ann Henry
- St. James's Institute of Oncology, Leeds, UK.
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Murray L, Henry A, Hoskin P, Siebert FA, Venselaar J. Second primary cancers after radiation for prostate cancer: a review of data from planning studies. Radiat Oncol 2013; 8:172. [PMID: 23835163 PMCID: PMC3724744 DOI: 10.1186/1748-717x-8-172] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 06/23/2013] [Indexed: 11/29/2022] Open
Abstract
A review of planning studies was undertaken to evaluate estimated risks of radiation induced second primary cancers (RISPC) associated with different prostate radiotherapy techniques for localised prostate cancer. A total of 83 publications were identified which employed a variety of methods to estimate RISPC risk. Of these, the 16 planning studies which specifically addressed absolute or relative second cancer risk using dose-response models were selected for inclusion within this review. There are uncertainties and limitations related to all the different methods for estimating RISPC risk. Whether or not dose models include the effects of the primary radiation beam, as well as out-of-field regions, influences estimated risks. Regarding the impact of IMRT compared to 3D-CRT, at equivalent energies, several studies suggest an increase in risk related to increased leakage contributing to out-of-field RISPC risk, although in absolute terms this increase in risk may be very small. IMRT also results in increased low dose normal tissue irradiation, but the extent to which this has been estimated to contribute to RISPC risk is variable, and may also be very small. IMRT is often delivered using 6MV photons while conventional radiotherapy often requires higher energies to achieve adequate tissue penetration, and so comparisons between IMRT and older techniques should not be restricted to equivalent energies. Proton and brachytherapy planning studies suggest very low RISPC risks associated with these techniques. Until there is sufficient clinical evidence regarding RISPC risks associated with modern irradiation techniques, the data produced from planning studies is relevant when considering which patients to irradiate, and which technique to employ.
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Affiliation(s)
- Louise Murray
- St James’s Institute of Oncology, Beckett St, Leeds LS9 7TF, UK
- University of Leeds, Leeds, UK
| | - Ann Henry
- St James’s Institute of Oncology, Beckett St, Leeds LS9 7TF, UK
- University of Leeds, Leeds, UK
| | - Peter Hoskin
- Mount Vernon Cancer Centre, Northwood, London, UK
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Thomadsen B, DeWerd L, Ibbott G, Meigooni A, Mitch M, Rivard M, Stump K, Venselaar J. 93 TG-138 REPORT: UNCERTAINTIES IN PHOTON EMITTING BRACHYTHERAPY SOURCE DOSIMETRY. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)72060-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Zourari K, Ballester F, Baltas D, Papagiannis P, Pérez-Calatayud J, Venselaar J. 421 poster CALCULATION OF BRACHYTHERAPY BROAD BEAM TRANSMISSION FACTORS USING MC GENERATED MONOENERGETIC DATA*. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)70543-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Guedea F, Venselaar J, Hoskin P, Hellebust TP, Peiffert D, Londres B, Ventura M, Mazeron JJ, Limbergen EV, Pötter R, Kovacs G. Patterns of care for brachytherapy in Europe: Updated results. Radiother Oncol 2010; 97:514-20. [PMID: 20950878 DOI: 10.1016/j.radonc.2010.09.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 09/06/2010] [Indexed: 10/19/2022]
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Polo A, Salembier C, Venselaar J, Hoskin P. Review of intraoperative imaging and planning techniques in permanent seed prostate brachytherapy. Radiother Oncol 2010; 94:12-23. [PMID: 20074822 DOI: 10.1016/j.radonc.2009.12.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Revised: 11/28/2009] [Accepted: 12/21/2009] [Indexed: 11/26/2022]
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Essers M, Hol S, de Kruijf W, Venselaar J, Martens R, Raaijmakers E, Eekers D, van de Pol M. OVERALL ACCURACY OF INTRACRANIAL STEREOTACTIC TREATMENTS USING A VARIAN TRILOGY AND THE CMS TPS. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(12)73255-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Raaijmakers E, Jongste W, Smits B, Hol S, Venselaar J, van de Pol M, Eekers D, Essers M. EVALUATION OF ROUTINE MRI FROM REFERRING HOSPITALS FOR INTRACRANIAL STEREOTACTIC RADIOTHERAPY; CT-MR REGISTRATION ERRORS IN CMS FOCAL. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(12)73078-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Evers J, Davits R, Kupper N, Engelen A, Venselaar J. 58 oral: Influence of Hormonal Treatment on Quality of Life After Brachytherapy for Prostate Cancer. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(15)34315-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Guedea F, Venselaar J, Ventura M, Londres B, Van Limbergen E, Mazeron J, National coordinators P. 149 poster: Patterns of Care for Brachytherapy (PCB): Preliminary Results. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(15)34406-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Venselaar J, Ballester F, Baltas D, Gimeno J, Granero D, Papagiannis P, Perez-Calatayud J. Broad beam transmission data for the shielding of brachytherapy facilities. Brachytherapy 2008. [DOI: 10.1016/j.brachy.2008.02.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Siebert FA, De Brabandere M, Kirisits C, Kovacs G, Venselaar J. Seed imaging and reconstruction quality of different CT parameters and various seed models. Brachytherapy 2008. [DOI: 10.1016/j.brachy.2008.02.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Siebert FA, De Brabandere M, Kirisits C, Kovács G, Venselaar J. Phantom investigations on CT seed imaging for interstitial brachytherapy. Radiother Oncol 2007; 85:316-23. [PMID: 17884213 DOI: 10.1016/j.radonc.2007.04.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 04/13/2007] [Accepted: 04/23/2007] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND PURPOSE The Braphyqs group (BRAchytherapy PHYsics Quality System, the brachytherapy physicist's task group of GEC-ESTRO) investigated the quality of CT- and X-ray based seed reconstruction procedures using the Kiel-phantom. In this study systematic phantom investigations on CT post-planning and the results of a mailed multi-centre inter-comparison are presented. MATERIALS AND METHODS The phantom was equipped with a test configuration composed of 17 non-radioactive seeds. To investigate the quality of seed reconstruction CT measurements with varying CT parameters and different seed models were carried out. In a mailed multi-centre approach the phantom was sent to six European seed centres. The centres performed a typical CT- or X-ray based post-planning. The coordinates of the reconstructed sources were compared with the known positions in the phantom. RESULTS In the systematic study it was found for the used CT scanner and seed models that when the slice thickness or the table index (respectively, an appropriate pitch for helical scans) reaches 4 or 5mm the accuracy of the CT seed reconstruction decreases in longitudinal direction. No influences of scanned field of view, tube current, kV(p), or scan type (axial or spiral) on seed reconstruction accuracy were detected. This finding was confirmed by the multi-centre evaluation. It was demonstrated that the Kiel-phantom is a suitable quality assurance (QA) tool for the assessment of the seed reconstruction accuracy in post-implant procedures and that it is a feasible QA test tool for a mailed multi-centre approach. CONCLUSIONS QA of seed post-planning is necessary. A trend was observed that when the slice thickness and table index is 4 or 5mm the standard deviation of the reconstructed seeds increases for CT-based post-planning. Individual optimizations can be performed with dedicated phantoms.
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Affiliation(s)
- Frank-André Siebert
- University Hospital of Schleswig-Holstein, Clinic of Radiotherapy, Kiel, Germany.
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Kirisits C, Siebert FA, Baltas D, De Brabandere M, Hellebust TP, Berger D, Venselaar J. Accuracy of volume and DVH parameters determined with different brachytherapy treatment planning systems. Radiother Oncol 2007; 84:290-7. [PMID: 17698231 DOI: 10.1016/j.radonc.2007.06.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 05/29/2007] [Accepted: 06/13/2007] [Indexed: 10/23/2022]
Abstract
PURPOSE To determine the uncertainties in dose volume histogram (DVH) analysis used in modern brachytherapy treatment planning systems (TPSs). MATERIALS AND METHODS A phantom with three different volumes was scanned with CT and MRI. An inter-observer analysis was based on contouring performed by 5 persons. The volume of a standard contour set was calculated using seven different TPSs. For five systems a typical brachytherapy dose distribution was used to compare DVH determination. RESULTS The inter-observer variability (1SD) was 13% for a small cylindrical volume, 5% for a large cylinder and 3% for a conical shape. A standardized volume for a 4mm CT scan contoured on seven different TPS varied by 7%, 2%, and 5% (1SD). Use of smaller slice thickness reduced the variations. A treatment plan with the sources between the large cylindrical shape and the cone showed variations for D(2cc) of 1% and 5% (1SD), respectively. Deviations larger than 10% were observed for a smaller source to cylinder surface distance of 5mm. CONCLUSIONS Modern TPSs minimize the volumetric and dosimetric calculation uncertainties. These are comparable to inter-observer contouring variations. However, differences in volume result from the methods of calculation in the first and last slice of a contoured structure. For this situation and in case of high dose gradients inside analyzed volumes, high uncertainties were observed. The use of DVH parameters in clinical practice should take into account the method of calculation and the possible uncertainties.
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Affiliation(s)
- Christian Kirisits
- Department of Radiotherapy, Medical University of Vienna, Vienna, Austria.
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Hoskin PJ, Venselaar J. Prostate brachytherapy in Europe: Growth, practice and guidelines. Radiother Oncol 2007; 83:1-2. [PMID: 17343937 DOI: 10.1016/j.radonc.2007.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
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Salembier C, Lavagnini P, Nickers P, Mangili P, Rijnders A, Polo A, Venselaar J, Hoskin P. Tumour and target volumes in permanent prostate brachytherapy: A supplement to the ESTRO/EAU/EORTC recommendations on prostate brachytherapy. Radiother Oncol 2007; 83:3-10. [PMID: 17321620 DOI: 10.1016/j.radonc.2007.01.014] [Citation(s) in RCA: 228] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 01/17/2007] [Accepted: 01/29/2007] [Indexed: 11/26/2022]
Abstract
The aim of this paper is to supplement the GEC/ESTRO/EAU recommendations for permanent seed implantations in prostate cancer to develop consistency in target and volume definition for permanent seed prostate brachytherapy. Recommendations on target and organ at risk (OAR) definitions and dosimetry parameters to be reported on post implant planning are given.
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Affiliation(s)
- Carl Salembier
- Department of Radiation Oncology, Europe Hospitals, Brussels, Belgium
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Guedea F, Ellison T, Venselaar J, Borras JM, Hoskin P, Poetter R, Heeren G, Nisin R, François G, Mazeron JJ, Limbergen EV, Ventura M, Taillet M, Cottier B. Overview of brachytherapy resources in Europe: A survey of patterns of care study for brachytherapy in Europe. Radiother Oncol 2007; 82:50-4. [PMID: 17150270 DOI: 10.1016/j.radonc.2006.11.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 11/17/2006] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND PURPOSE The Patterns of Care for Brachytherapy in Europe (PCBE) study is aimed at establishing a detailed information system on brachytherapy throughout Europe. MATERIALS AND METHODS The questionnaire was web-based and the analysis used data from each radiotherapy department with brachytherapy. There were three groups: Group I with 19 countries (15 initial European Community (EC) countries plus Iceland, Monaco, Norway and Switzerland -EC+4-), Group II with 10 countries (New European Community countries -NEC-) and Group III with 14 countries (Other European Countries -OEC-). RESULTS In the European area there are 36 of 43 countries (85%) which achieved data collection from at least 50% of centres, and were included in the analysis. The tumour site that had the largest number of treated patients was gynaecological tumours. Several variations have been found in the mean number of patients treated per consultant radiation oncologist and physicist; and in the proportion of brachytherapy patients with gynaecology, prostate and breast tumours, by country and by European area. The provided data showed that the average number of brachytherapy patients per centre increased by 10% between 1997 and 2002. CONCLUSIONS A European wide evaluation of brachytherapy practice using a web-based questionnaire is feasible and that there is considerable variation in both patterns of practice and available resources.
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Affiliation(s)
- Ferran Guedea
- Department of Radiation Oncology, Institut Català d'Oncologia - IDIBELL, L'Hospitalet del Llobregat, Barcelona, Spain.
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Abstract
In this work, the dose rate distribution of a new Ir-192 high dose rate source (Flexisource used in the afterloading Flexitron system, Isodose Control, Veenendaal, The Netherlands) is studied by means of Monte Carlo techniques using the GEANT4 code. The dosimetric parameters of the Task Group No. 43 Report (TG43) formalism and two-dimensional rectangular look-up tables have been obtained.
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Affiliation(s)
- D Granero
- Physics Section, Radiation Oncology Department, "La Fe" University Hospital, Avd. Campanar 21, E46009 Valencia, Spain
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Casal E, Perez-Calatayud J, Granero D, Ballester F, Cases R, Venselaar J. SU-FF-T-329: Monte Carlo Dosimetric Study of the Flexisource Ir-192 HDR Source. Med Phys 2006. [DOI: 10.1118/1.2241251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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21
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Siebert FA, De Brabandere M, Kirisits C, Venselaar J. Quality assurance of seed implants using CT/MRI phantoms. Brachytherapy 2006. [DOI: 10.1016/j.brachy.2006.03.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Granero D, Pérez-Calatayud J, Ballester F, Bos AJJ, Venselaar J. Broad-beam transmission data for new brachytherapy sources, Tm-170 and Yb-169. Radiat Prot Dosimetry 2006; 118:11-5. [PMID: 16030058 DOI: 10.1093/rpd/nci322] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The characteristics of the radionuclides (170)Tm and (169)Yb are highly interesting for their use as high dose-rate brachytherapy sources. The introduction of brachytherapy equipment containing these sources will lead to smaller required thicknesses of the materials used in radiation protection barriers compared with the use of conventional sources such as (192)Ir and (137)Cs. The purpose of this study is to determine the required thicknesses of protection material for the design of the protecting walls. Using the Monte Carlo method, transmission data were derived for broad-beam geometries through lead and concrete barriers, from which the first half value layer and tenth value layer are obtained. In addition, the dose reduction in a simulated patient was studied to determine whether transmission in the patient is a relevant factor in radiation protection calculations.
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Affiliation(s)
- Domingo Granero
- Department of Atomic, Molecular and Nuclear Physics, University of Valencia and IFIC, C/Dr Moliner 50, E46100 Burjassot, Spain
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Abstract
Although the relevance and importance of quality assurance and quality control in radiotherapy is generally accepted, only recently, methods for monitor unit (MU) calculation and verification have been addressed in recognized recommendations, published by the European Society of Therapeutic Radiation Oncology (ESTRO) and by the Netherlands Commission on Radiation Dosimetry (Dutreix A, Bjärngard BE, Bridier A, Mijnheer B, Shaw JE, Svensson H. Monitor unit calculation for high-energy photon beams. Physics for clinical radiotherapy. ESTRO Booklet No. 3. Leuven: Garant, 1997; Netherlands Commission on Radiation Dosimetry (NCS). Determination and use of scatter correction factors of megavoltage photon beams. NCS report 12. Deift: NCS, 1998). Both documents are based on the same principles: (i) the separation of the output factor into a head and a volume (or phantom) scatter component; (ii) the use of a so-called mini-phantom to measure and verify the head scatter component; and (iii) the recommendation to use a single reference depth of 10 cm for all photon beam qualities. However, there are substantial differences between the approach developed in the IAEA-ESTRO task group and the NCS approach for MU calculations, which might lead to confusion and/or misinterpretation if both reports are used simultaneously or if data from the NCS report is applied in the algorithms of the ESTRO report without careful consideration. The aim of the present paper is to discuss and to clearly point out these differences (e.g. field size definitions, phantom scatter parameters, etc.). Additionally, corresponding quantities in the two reports are related where possible and several aspects concerning the use of a mini-phantom (e.g. size, detector position, composition) are addressed.
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Affiliation(s)
- D Georg
- Department of Radiotherapy and Radiobiology, AKH Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
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Venselaar J, Welleweerd H. Application of a test package in an intercomparison of the photon dose calculation performance of treatment planning systems used in a clinical setting. Radiother Oncol 2001; 60:203-13. [PMID: 11439215 DOI: 10.1016/s0167-8140(01)00304-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Testing the performance of treatment planning systems by using the AAPM Task Group 23 test package is a useful approach, but has its limitations. To be able to include technical developments, such as the asymmetric collimator, it was decided to remeasure the AAPM data set on more modern radiotherapy equipment, to extend the test geometries, and to evaluate the use of the new package. MATERIALS AND METHODS A coherent set of beam data of 6, 10 and 18 MV photon beams was measured on two modern linear accelerators. These data served as input data in seven commercially available treatment planning systems, which were clinically in use in different radiotherapy departments. Next, a test package was measured which included a missing tissue geometry and fields with asymmetrical collimator setting, with and without a wedge. RESULTS The absolute dose prediction from the different treatment planning systems in which the measured beam data were entered, was compared for all test points with the results of direct measurements. The criteria of acceptability were exceeded by some systems in cases of irregular field geometry and missing tissue geometry. The majority of the systems had difficulties with accurate dose calculation for asymmetrically wedged fields. CONCLUSIONS The application of the new test package did not introduce insuperable difficulties and was highly appreciated by the participating centres. Most systems performed reasonably well for the majority of the beam geometries, with the exception of asymmetrically wedged beams. The extended test package is available for other users or user groups for the purpose of commissioning new treatment planning systems, or new releases of existing systems.
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Affiliation(s)
- J Venselaar
- Department of Radiotherapy, Dr B. Verbeeten Institute, P.O. Box 90120, 5000 LA, The, Tilburg, Netherlands
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Abstract
BACKGROUND AND PURPOSE To design a consistent set of criteria for acceptability of photon beam dose calculations of treatment planning systems. The set should be applicable in combination with a test package used for evaluation of a treatment planning system, such as the ones proposed by the AAPM Task Group 23 or by the Netherlands Commission on Radiation Dosimetry. RESULTS Tolerances have been defined for the accuracy with which a treatment planning system should be able to calculate the dose in different parts of a photon beam: the central beam axis and regions with large and small dose gradients. For increasing complexity of the geometry, wider tolerances are allowed, varying between 2 and 5%. For the evaluation of a large number of data points an additional quantity, the confidence limit, has been introduced, which combines the influence of systematic and random deviations. The proposed tolerances have been compared with other recommendations for a number of clinically relevant examples, showing considerable differences, which are partly due to the way the complexity of the geometry is taken into account. Furthermore differences occur if criteria for acceptability of dose calculations are related either to the local dose value or to a normalized dose value. CONCLUSIONS Although it is acknowledged that the general aim must be to have good agreement between dose calculation and the actual dose value, e.g. within 2% or 2 mm, current day algorithms and their implementation into commercial treatment planning systems result often in larger deviations. A high accuracy can at present only be achieved in relatively simple cases. The new set of tolerances and the quantity confidence limit have proven to be useful tools for the acceptance of photon beam dose calculation algorithms of treatment planning systems.
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Affiliation(s)
- J Venselaar
- Department of Radiotherapy, Dr. B. Verbeeten Institute, P.O. Box 90120, 5000 LA, Tilburg, The Netherlands
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Heeren G, Barrett A, Baumann M, Dutreix A, Huyskens D, Lartgau E, Mijnheer B, Venselaar J, Svensson H. 20. Setting the pace for strengthening radiotherapy in Europe: the estro esquire project. Rep Pract Oncol Radiother 2001. [DOI: 10.1016/s1507-1367(01)70390-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Rodrigus P, Venselaar J, De Winter K. 66 The influence of dose rate changes on the late morbidity in patients with stage IIB and IIIB uterine cervix cancer. Radiother Oncol 2001. [DOI: 10.1016/s0167-8140(01)80072-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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van Kleffens H, Venselaar J, Heukelom S, Jager N, Mijnheer B, van der Laarse R, van Gasteren H, Westermann C. Dependence of the tray transmission factor on collimator setting and source-surface distance. Med Phys 2000; 27:2117-23. [PMID: 11011741 DOI: 10.1118/1.1288240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
When blocks are placed on a tray in megavoltage x-ray beams, generally a single correction factor for the attenuation by the tray is applied for each photon beam quality. In this approach, the tray transmission factor is assumed to be independent of field size and source-surface distance (SSD). Analysis of a set of measurements performed in beams of 13 different linear accelerators demonstrates that there is, however, a slight variation of the tray transmission factor with field size and SSD. The tray factor changes about 1.5% for collimator settings varying between 4x4 cm and 40 x 40 cm for a 1 cm thick PMMA tray and approximately 3% for a 2 cm thick PMMA tray. The variation with field size is smaller if the source-surface distance is increased. The dependence on the collimator setting is not different, within the experimental uncertainty of about 0.5% (1 s.d.), for the nominal accelerating potentials and accelerator types applied in this study. It is shown that the variation of the tray transmission factor with field size and source-surface distance can easily be taken into account in the dose calculation by considering the volume of the irradiated tray material and the position of the tray in the beam. A relation is presented which can be used to calculate the numerical value of the tray transmission factor directly. These calculated values can be checked with only a few measurements using a cylindrical beam coaxial miniphantom.
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Affiliation(s)
- H van Kleffens
- Department of Radiotherapy, University Medical Center, Utrecht, The Netherlands.
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Venselaar J, Heukelom S, Jager N, Mijnheer B, van der Laarse R, van Gasteren H, van Kleffens H, Westermann C. Response to “Comment on ‘The effect of electron contamination on scatter correction factors for photon beam dosimetry’ ” [Med. Phys. 27, 616 (2000)]. Med Phys 2000. [DOI: 10.1118/1.598901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Venselaar J, Heukelom S, Jager N, Mijnheer B, van der Laarse R, van Gasteren H, van Kleffens H, Westermann C. Effect of electron contamination on scatter correction factors for photon beam dosimetry. Med Phys 1999; 26:2099-106. [PMID: 10535626 DOI: 10.1118/1.598725] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Physical quantities for use in megavoltage photon beam dose calculations which are defined at the depth of maximum absorbed dose are sensitive to electron contamination and are difficult to measure and to calculate. Recently, formalisms have therefore been presented to assess the dose using collimator and phantom scatter correction factors, Sc and Sp, defined at a reference depth of 10 cm. The data can be obtained from measurements at that depth in a miniphantom and in a full scatter phantom. Equations are presented that show the relation between these quantities and corresponding quantities obtained from measurements at the depth of the dose maximum. It is shown that conversion of Sc and Sp determined at a 10 cm depth to quantities defined at the dose maximum such as (normalized) peak scatter factor, (normalized) tissue-air ratio, and vice versa is not possible without quantitative knowledge of the electron contamination. The difference in Sc at dmax resulting from this electron contamination compared with Sc values obtained at a depth of 10 cm in a miniphantom has been determined as a multiplication factor, Scel, for a number of photon beams of different accelerator types. It is shown that Scel may vary up to 5%. Because in the new formalisms output factors are defined at a reference depth of 10 cm, they do not require Scel data. The use of Sc and Sp values, defined at a 10 cm depth, combined with relative depth-dose data or tissue-phantom ratios is therefore recommended. For a transition period the use of the equations provided in this article and Scel data might be required, for instance, if treatment planning systems apply Sc data normalized at d(max).
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Affiliation(s)
- J Venselaar
- Department of Radiotherapy, Dr. B. Verbeetan Institute, Tilburg, The Netherlands.
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