51
|
Chicas-Sett R, Bautista-Ballesteros J, Celada-Alvarez F, Roldán S, Torregrosa A, Betancourt J, Burgos J, Farga D, Perez M, Carmona V, Tormo A, Benlloch J, Perez-Calatayud J. EP-2008: Robustness of the OARs recommendations made by GEC-ESTRO according to inter-observer variability. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)33259-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
52
|
Candela-Juan C, Vijande J, García-Martínez T, Niatsetski Y, Nauta G, Schuurman J, Ouhib Z, Ballester F, Perez-Calatayud J. Response to “Comment on ‘Comparison and uncertainty evaluation of different calibration protocols and ionization chambers for low-energy surface brachytherapy dosimetry’ ” [Med. Phys. 42
, 4954-4964 (2015)]. Med Phys 2016; 43:2007. [DOI: 10.1118/1.4942807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
53
|
Candela-Juan C, Niatsetski Y, van der Laarse R, Granero D, Ballester F, Perez-Calatayud J, Vijande J. Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions. Med Phys 2016; 43:1639. [DOI: 10.1118/1.4943381] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
54
|
Tornero-López AM, Torres del Río J, Ruiz C, Perez-Calatayud J, Guirado D, Lallena AM. Characterization of the PTW SourceCheck ionization chamber with the Valencia lodgment for 125 I seed verification. Phys Med 2015; 31:922-928. [DOI: 10.1016/j.ejmp.2015.07.142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 06/19/2015] [Accepted: 07/13/2015] [Indexed: 10/22/2022] Open
|
55
|
Palomo R, Pujades MC, Gimeno-Olmos J, Carmona V, Lliso F, Candela-Juan C, Vijande J, Ballester F, Perez-Calatayud J. Evaluation of lens absorbed dose with Cone Beam IGRT procedures. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2015; 35:N33-N41. [PMID: 26457404 DOI: 10.1088/0952-4746/35/4/n33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
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.
Collapse
|
56
|
Sett RC, Celada F, Roldan S, Soler A, Burgos J, Gimeno J, Perez-Calatayud J. Early Toxicity Outcomes: A Single 15-Gy Fraction High-Dose-Rate Brachytherapy as Pretreatment External Beam Radiation Therapy Boost in Prostate Cancer. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.1075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
57
|
Candela-Juan C, Vijande J, García-Martínez T, Niatsetski Y, Nauta G, Schuurman J, Ouhib Z, Ballester F, Perez-Calatayud J. Comparison and uncertainty evaluation of different calibration protocols and ionization chambers for low-energy surface brachytherapy dosimetry. Med Phys 2015; 42:4954-64. [PMID: 26233221 DOI: 10.1118/1.4927059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
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.
Collapse
|
58
|
Nuñez-Cumplido E, Perez-Calatayud J, Casares-Magaz O, Hernandez-Armas J. Influence of source batch S dispersion on dosimetry for prostate cancer treatment with permanent implants. Med Phys 2015; 42:4933-40. [PMID: 26233219 DOI: 10.1118/1.4926848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In clinical practice, specific air kerma strength (SK) value is used in treatment planning system (TPS) permanent brachytherapy implant calculations with (125)I and (103)Pd sources; in fact, commercial TPS provide only one SK input value for all implanted sources and the certified shipment average is typically used. However, the value for SK is dispersed: this dispersion is not only due to the manufacturing process and variation between different source batches but also due to the classification of sources into different classes according to their SK values. The purpose of this work is to examine the impact of SK dispersion on typical implant parameters that are used to evaluate the dose volume histogram (DVH) for both planning target volume (PTV) and organs at risk (OARs). METHODS The authors have developed a new algorithm to compute dose distributions with different SK values for each source. Three different prostate volumes (20, 30, and 40 cm(3)) were considered and two typical commercial sources of different radionuclides were used. Using a conventional TPS, clinically accepted calculations were made for (125)I sources; for the palladium, typical implants were simulated. To assess the many different possible SK values for each source belonging to a class, the authors assigned an SK value to each source in a randomized process 1000 times for each source and volume. All the dose distributions generated for each set of simulations were assessed through the DVH distributions comparing with dose distributions obtained using a uniform SK value for all the implanted sources. The authors analyzed several dose coverage (V100 and D90) and overdosage parameters for prostate and PTV and also the limiting and overdosage parameters for OARs, urethra and rectum. RESULTS The parameters analyzed followed a Gaussian distribution for the entire set of computed dosimetries. PTV and prostate V100 and D90 variations ranged between 0.2% and 1.78% for both sources. Variations for the overdosage parameters V150 and V200 compared to dose coverage parameters were observed and, in general, variations were larger for parameters related to (125)I sources than (103)Pd sources. For OAR dosimetry, variations with respect to the reference D0.1cm(3) were observed for rectum values, ranging from 2% to 3%, compared with urethra values, which ranged from 1% to 2%. CONCLUSIONS Dose coverage for prostate and PTV was practically unaffected by SK dispersion, as was the maximum dose deposited in the urethra due to the implant technique geometry. However, the authors observed larger variations for the PTV V150, rectum V100, and rectum D0.1cm(3) values. The variations in rectum parameters were caused by the specific location of sources with SK value that differed from the average in the vicinity. Finally, on comparing the two sources, variations were larger for (125)I than for (103)Pd. This is because for (103)Pd, a greater number of sources were used to obtain a valid dose distribution than for (125)I, resulting in a lower variation for each SK value for each source (because the variations become averaged out statistically speaking).
Collapse
|
59
|
Hueso-González F, Vijande J, Ballester F, Perez-Calatayud J, Siebert FA. A simple analytical method for heterogeneity corrections in low dose rate prostate brachytherapy. Phys Med Biol 2015; 60:5455-69. [PMID: 26118956 DOI: 10.1088/0031-9155/60/14/5455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In low energy brachytherapy, the presence of tissue heterogeneities contributes significantly to the discrepancies observed between treatment plan and delivered dose. In this work, we present a simplified analytical dose calculation algorithm for heterogeneous tissue. We compare it with Monte Carlo computations and assess its suitability for integration in clinical treatment planning systems. The algorithm, named as RayStretch, is based on the classic equivalent path length method and TG-43 reference data. Analytical and Monte Carlo dose calculations using Penelope2008 are compared for a benchmark case: a prostate patient with calcifications. The results show a remarkable agreement between simulation and algorithm, the latter having, in addition, a high calculation speed. The proposed analytical model is compatible with clinical real-time treatment planning systems based on TG-43 consensus datasets for improving dose calculation and treatment quality in heterogeneous tissue. Moreover, the algorithm is applicable for any type of heterogeneities.
Collapse
|
60
|
Ibanez-Rosello B, Bautista J, Candela-Juan C, Villaescusa J, Ballester F, Perez-Calatayud J. SU-E-T-691: Shielding Evaluation of a Treatment Room with An Electronic Brachytherapy System. Med Phys 2015. [DOI: 10.1118/1.4925054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
61
|
Candela-Juan C, Garcia-Martinez T, Niatsetski Y, Schuurman J, Nauta G, Vijande J, Ouhib Z, Ballester F, Perez-Calatayud J. SU-E-T-720: Surface Electronic Brachytherapy Dosimetry: Comparison and Uncertainty Evaluation of Different Calibration Protocols and Ionization Chambers. Med Phys 2015. [DOI: 10.1118/1.4925084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
62
|
Lliso F, Carmona V, Gimeno J, Candela-Juan C, Bautista J, Richart J, Perez-Calatayud J. SU-E-T-229: Craniospinal Radiotherapy Planning with VMAT, Two First Years Experience. Med Phys 2015. [DOI: 10.1118/1.4924590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
63
|
Abad D, Ruiz C, Candela-Juan C, Carmona V, Gimeno J, Lliso F, Ballester F, Perez-Calatayud J. EP-1386: Evaluation of ArcCHECK for pretreatment QA of VMAT for very small volumes in SRS and SBRT with FF and FFF beams. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)41378-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
64
|
Lliso F, Carmona V, Gimeno J, Candela C, Ruiz C, Perez-Calatayud J. EP-1564: TrueBeam RapidArc implementation of radiosurgery for benign lesions: first year experience. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)41556-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
65
|
Perez-Calatayud J. SP-0599: Commissioning and QA of skin electronic brachytherapy applicators. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40593-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
66
|
Perez-Calatayud J, Candela-Juan C, Vijande J, Ouhib Z, García-Martínez T, Niatsetski Y, Nauta G, Schuurman J, Ballester F. PD-0186: Dosimetric evaluation of the electronic brachytherapy system Esteya. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40184-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
67
|
Pons O, Ballester R, Hernandez M, Botella R, Ballesta A, Tormo A, Celada F, Rodriguez S, Santos M, Ballester F, Perez-Calatayud J. EP-1613: Depth determination of skin cancers treated with superficial barchytherapy: ultrasound vs. histopathology. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)41605-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
68
|
Chicas Sett R, Soler A, Fernandez J, Burgos J, Pons O, Roldan S, Celada F, Gimeno J, Tormo A, Perez-Calatayud J. PO-0723: Early toxicity outcomes: A single 15Gy fraction HDR brachytherapy as pre-treatment EBRT boost in prostate cancer. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40715-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
69
|
Candela-Juan C, Gimeno-Olmos J, Pujades M, Rivard M, Carmona V, Lliso F, Celada F, Ramírez-Coves J, Ballester F, Tormo A, Perez-Calatayud J. EP-1590: Shielding design and fetal dose evaluation of a breast cancer pregnant patient undergoing HDR Ir-192 brachytherapy. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)41582-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
70
|
Celada F, Chicas R, Soler A, Roldan S, Candela C, Gimeno J, Tormo A, Perez-Calatayud J. EP-1256: Salvage iodine-125 brachytherapy for local prostate cancer recurrence after radiotherapy. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)41248-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
71
|
Ballester-Sánchez R, Pons-Llanas O, Llavador-Ros M, Botella-Estrada R, Ballester-Cuñat A, Tormo-Micó A, Javier Celadá-Álvarez F, Rodríguez-Villalba S, Santos-Ortega M, Ballester-Pallarés F, Perez-Calatayud J. Depth determination of skin cancers treated with superficial brachytherapy: ultrasound vs. histopathology. J Contemp Brachytherapy 2015; 6:356-61. [PMID: 25834579 PMCID: PMC4300362 DOI: 10.5114/jcb.2014.47860] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 10/20/2014] [Accepted: 11/08/2014] [Indexed: 02/07/2023] Open
Abstract
PURPOSE The purpose of this study is to compare high frequency ultrasonography (HFUS) and histpathologic assessment done by punch biopsy in order to determine depth of basal cell carcinoma (BCC), in both superficial and nodular BCCs prior to brachytherapy treatment. MATERIAL AND METHODS This study includes 20 patients with 10 superficial and 10 nodular BCCs. First, punch biopsy was done to confirm the diagnosis and to measure tumour depth (Breslow rate). Subsequently, HFUS was done to measure tumour depth to search for correlation of these two techniques. RESULTS Neither clear tendency nor significance of the punch biopsy vs. HFUS depth determination is observed. Depth value differences with both modalities resulted patient dependent and then consequence of its uncertainty. Conceptually, HFUS should determine the macroscopic lesion (gross tumour volume - GTV), while punch biopsy is able to detect the microscopic extension (clinical target volume - CTV). Uncertainties of HFUS are difficult to address, while punch biopsy is done just on a small lesion section, not necessarily the deepest one. CONCLUSIONS According to the results, HFUS is less accurate at very shallow depths. Nodular cases present higher depth determination differences than superficial ones. In our clinical practice, we decided to prescribe at 3 mm depth when HFUS measurements give depth lesion values smaller than this value.
Collapse
|
72
|
Pujades MC, Granero D, Vijande J, Ballester F, Perez-Calatayud J, Papagiannis P, Siebert FA. Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2014; 34:741-753. [PMID: 25222942 DOI: 10.1088/0952-4746/34/4/741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
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.
Collapse
|
73
|
Gimeno J, Pujades M, García T, Carmona V, Lliso F, Palomo R, Candela-Juan C, Richart J, Perez-Calatayud J. Commissioning and initial experience with a commercial software for in vivo volumetric dosimetry. Phys Med 2014; 30:954-9. [DOI: 10.1016/j.ejmp.2014.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/12/2014] [Accepted: 06/10/2014] [Indexed: 11/29/2022] Open
|
74
|
Granero D, Perez-Calatayud J, Vijande J, Ballester F, Rivard MJ. Limitations of the TG-43 formalism for skin high-dose-rate brachytherapy dose calculations. Med Phys 2014; 41:021703. [PMID: 24506594 DOI: 10.1118/1.4860175] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In skin high-dose-rate (HDR) brachytherapy, sources are located outside, in contact with, or implanted at some depth below the skin surface. Most treatment planning systems use the TG-43 formalism, which is based on single-source dose superposition within an infinite water medium without accounting for the true geometry in which conditions for scattered radiation are altered by the presence of air. The purpose of this study is to evaluate the dosimetric limitations of the TG-43 formalism in HDR skin brachytherapy and the potential clinical impact. METHODS Dose rate distributions of typical configurations used in skin brachytherapy were obtained: a 5 cm × 5 cm superficial mould; a source inside a catheter located at the skin surface with and without backscatter bolus; and a typical interstitial implant consisting of an HDR source in a catheter located at a depth of 0.5 cm. Commercially available HDR(60)Co and (192)Ir sources and a hypothetical (169)Yb source were considered. The Geant4 Monte Carlo radiation transport code was used to estimate dose rate distributions for the configurations considered. These results were then compared to those obtained with the TG-43 dose calculation formalism. In particular, the influence of adding bolus material over the implant was studied. RESULTS For a 5 cm × 5 cm(192)Ir superficial mould and 0.5 cm prescription depth, dose differences in comparison to the TG-43 method were about -3%. When the source was positioned at the skin surface, dose differences were smaller than -1% for (60)Co and (192)Ir, yet -3% for (169)Yb. For the interstitial implant, dose differences at the skin surface were -7% for (60)Co, -0.6% for (192)Ir, and -2.5% for (169)Yb. CONCLUSIONS This study indicates the following: (i) for the superficial mould, no bolus is needed; (ii) when the source is in contact with the skin surface, no bolus is needed for either (60)Co and (192)Ir. For lower energy radionuclides like (169)Yb, bolus may be needed; and (iii) for the interstitial case, at least a 0.1 cm bolus is advised for (60)Co to avoid underdosing superficial target layers. For (192)Ir and (169)Yb, no bolus is needed. For those cases where no bolus is needed, its use might be detrimental as the lack of radiation scatter may be beneficial to the patient, although the 2% tolerance for dose calculation accuracy recommended in the AAPM TG-56 report is not fulfilled.
Collapse
|
75
|
Carmona-Meseguer V, Garcia-Martinez T, Palomo-Llinares R, Candela-Juan C, Richart-Sancho J, Gimeno-Olmos J, Lliso-Valverde F, Granero D, Ballester F, Perez-Calatayud J. SU-E-T-343: Valencia Applicator Commissioning Using a Micro-Chamber Array. Med Phys 2014. [DOI: 10.1118/1.4888676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|