1
|
Kinhikar R, Kaushik S, Tambe C, Kadam S, Kale S, Upreti R. Implementation and Challenges of International Atomic Energy Agency/American Association of Physicists in Medicine TRS 483 Formalism for Field Output Factors and Involved Uncertainties Determination in Small Fields for TomoTherapy. J Med Phys 2021; 46:162-170. [PMID: 34703100 PMCID: PMC8491308 DOI: 10.4103/jmp.jmp_11_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 11/04/2022] Open
Abstract
PURPOSE International Atomic Energy Agency published TRS-483 to address the issues of small field dosimetry. Our study calculates the output factor in the small fields of TomoTherapy using different detectors and dosimetric conditions. Furthermore, it estimates the various components of uncertainty and presents challenges faced during implementation. MATERIALS AND METHODS Beam quality TPR20,10(10) at the hypothetical field size of 10 cm × 10 cm was calculated from TPR20,10(S). Two ionization chambers based on the minimum field width required to satisfy the lateral charge particle equilibrium and one unshielded electron field diode (EFD) were selected. Output factor measurements were performed in various dosimetric conditions. RESULTS Beam quality TPR20,10(10) has a mean value of 0.627 ± 0.001. The maximum variation of output factor between CC01 chamber and EFD diode at the smallest field size was 11.80%. In source to surface setup, the difference between water and virtual water was up to 9.68% and 8.13%, respectively, for the CC01 chamber and EFD diode. The total uncertainty in the ionization chamber was 2.43 times higher compared to the unshielded EFD diode at the smallest field size. CONCLUSIONS Beam quality measurements, chamber selection procedure, and output factors were successfully carried out. A difference of up to 10% in output factor can occur if density scaling for electron density in virtual water is not considered. The uncertainty in output correction factors dominates, while positional and meter reading uncertainty makes a minor contribution to total uncertainty. An unshielded EFD diode is a preferred detector in small fields because of lower uncertainty in measurements compared to ionization chambers.
Collapse
Affiliation(s)
- Rajesh Kinhikar
- Department of Medical Physics, Tata Memorial Centre, Parel, Mumbai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra, India
| | - Suryakant Kaushik
- Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre Kharghar, Navi Mumbai, Maharashtra, India
| | | | - Sudarshan Kadam
- Department of Medical Physics, Tata Memorial Centre, Parel, Mumbai, India
| | - Shrikant Kale
- Department of Medical Physics, Tata Memorial Centre, Parel, Mumbai, India
| | - Rituraj Upreti
- Department of Medical Physics, Tata Memorial Centre, Parel, Mumbai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra, India
| |
Collapse
|
2
|
Mirzakhanian L, Bassalow R, Zaks D, Huntzinger C, Seuntjens J. IAEA-AAPM TRS-483-based reference dosimetry of the new RefleXion biology-guided radiotherapy (BgRT) machine. Med Phys 2021; 48:1884-1892. [PMID: 33296515 DOI: 10.1002/mp.14631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/10/2020] [Accepted: 11/18/2020] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The purpose of this study is to provide data for the calibration of the recent RefleXion TM biology-guided radiotherapy (BgRT) machine (Hayward, CA, USA) following the International Atomic Energy Agency (IAEA) and the American Association of Physicists in Medicine (AAPM) TRS-483 code of practice (COP) (Palmans et al. International Atomic Energy Agency, Vienna, 2017) and (Mirzakhanian et al. Med Phys, 2020). METHODS In RefleXion BgRT machine, reference dosimetry was performed using two methodologies described in TRS-483 and (Mirzakhanian et al. Med Phys, 2020) In the first approach (Approach 1), the generic beam quality correction factor k Q A , Q 0 f A , f ref was calculated using an accurate Monte Carlo (MC) model of the beam and of six ionization chamber types. The k Q A , Q 0 f A , f ref is a beam quality factor that corrects N D , w , Q 0 f ref (absorbed dose to water calibration coefficient in a calibration beam quality Q 0 ) for the differences between the response of the chamber in the conventional reference calibration field f ref with beam quality Q 0 at the standards laboratory and the response of the chamber in the user's A field f A with beam quality Q A . Field A represents the reference calibration field that does not fulfill msr conditions. In the second approach (Approach 2), a square equivalent field size was determined for field A of 10 × 2 cm 2 and 10 × 3 cm 2 . Knowing the equivalent field size, the beam quality specifier for the hypothetical 10 × 10 cm 2 field size was derived. This was used to calculate the beam quality correction factor analytically for the six chamber types using the TRS-398. (Andreo et al. Int Atom Energy Agency 420, 2001) Here, TRS-398 was used instead of TRS-483 since the beam quality correction values for the chambers used in this study are not tabulated in TRS-483. The accuracy of Approach 2 is studied in comparison to Approach 1. RESULTS Among the chambers, the PTW 31010 had the largest k Q A , Q 0 f A , f ref correction due to the volume averaging effect. The smallest-volume chamber (IBA CC01) had the smallest correction followed by the other microchambers Exradin-A14 and -A14SL. The equivalent square fields sizes were found to be 3.6 cm and 4.8 cm for the 10 × 2 cm 2 and 10 × 3 cm 2 field sizes, respectively. The beam quality correction factors calculated using the two approaches were within 0.27% for all chambers except IBA CC01. The latter chamber has an electrode made of steel and the differences between the correction calculated using the two approaches was the largest, that is, 0.5%. CONCLUSIONS In this study, we provided the k Q A , Q 0 f A , f ref values as a function of the beam quality specifier at the RefleXion BgRT setup ( TPR 20 , 10 ( S ) and % d d ( 10 , S ) x ) for six chamber types. We suggest using the first approach for calibration of the RefleXion BgRT machine. However, if the MC correction is not available for a user's detector, the user can use the second approach for estimating the beam quality correction factor to sufficient accuracy (0.3%) provided the chamber electrode is not made of high Z material.
Collapse
Affiliation(s)
| | - Rostem Bassalow
- RefleXion Medical, 25841 Industrial Blvd, Hayward, California, 94545, USA
| | - Daniel Zaks
- RefleXion Medical, 25841 Industrial Blvd, Hayward, California, 94545, USA
| | - Calvin Huntzinger
- RefleXion Medical, 25841 Industrial Blvd, Hayward, California, 94545, USA
| | - Jan Seuntjens
- Medical Physics Unit, McGill University, Montreal, Quebec, H4A 3J1, Canada
| |
Collapse
|
3
|
Bouchard H. Reference dosimetry of modulated and dynamic photon beams. Phys Med Biol 2021; 65:24TR05. [PMID: 33438582 DOI: 10.1088/1361-6560/abc3fb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In the late 1980s, a new technique was proposed that would revolutionize radiotherapy. Now referred to as intensity-modulated radiotherapy, it is at the core of state-of-the-art photon beam delivery techniques, such as helical tomotherapy and volumetric modulated arc therapy. Despite over two decades of clinical application, there are still no established guidelines on the calibration of dynamic modulated photon beams. In 2008, the IAEA-AAPM work group on nonstandard photon beam dosimetry published a formalism to support the development of a new generation of protocols applicable to nonstandard beam reference dosimetry (Alfonso et al 2008 Med. Phys. 35 5179-86). The recent IAEA Code of Practice TRS-483 was published as a result of this initiative and addresses exclusively small static beams. But the plan-class specific reference calibration route proposed by Alfonso et al (2008 Med. Phys. 35 5179-86) is a change of paradigm that is yet to be implemented in radiotherapy clinics. The main goals of this paper are to provide a literature review on the dosimetry of nonstandard photon beams, including dynamic deliveries, and to discuss anticipated benefits and challenges in a future implementation of the IAEA-AAPM formalism on dynamic photon beams.
Collapse
Affiliation(s)
- Hugo Bouchard
- Département de physique, Université de Montréal, Complexe des sciences, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, Québec H2V 0B3, Canada. Centre de recherche du Centre hospitalier de l'Université de Montréal, 900 Rue Saint-Denis, Montréal, Québec H2X 0A9, Canada. Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1051 Rue Sanguinet, Montréal, Québec H2X 3E4, Canada
| |
Collapse
|
4
|
Lopes MDC, Santos T, Ventura T, Capela M. Application of the TRS 483 code of practice for reference and relative dosimetry in tomotherapy. Med Phys 2019; 46:5799-5806. [DOI: 10.1002/mp.13855] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/10/2019] [Accepted: 10/01/2019] [Indexed: 01/09/2023] Open
Affiliation(s)
| | - Tania Santos
- Medical Physics Department IPOCFG, E.P.E Coimbra Portugal
- Physics Department FCTUC University of Coimbra Coimbra Portugal
| | - Tiago Ventura
- Medical Physics Department IPOCFG, E.P.E Coimbra Portugal
| | - Miguel Capela
- Medical Physics Department IPOCFG, E.P.E Coimbra Portugal
| |
Collapse
|
5
|
Palmans H, Andreo P, Huq MS, Seuntjens J, Christaki KE, Meghzifene A. Dosimetry of small static fields used in external photon beam radiotherapy: Summary of TRS‐483, the IAEA–AAPM international Code of Practice for reference and relative dose determination. Med Phys 2018; 45:e1123-e1145. [DOI: 10.1002/mp.13208] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/24/2018] [Accepted: 07/30/2018] [Indexed: 12/18/2022] Open
Affiliation(s)
- Hugo Palmans
- Medical Radiation Science National Physical Laboratory Teddington TW11 0LWUK
- Department of Medical Physics EBG MedAustron GmbH A‐2700Wiener Neustadt Austria
| | - Pedro Andreo
- Department of Medical Physics and Nuclear Medicine Karolinska University Hospital SE‐17176Stockholm Sweden
| | - M. Saiful Huq
- Department of Radiation Oncology University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center Pittsburgh PA15232USA
| | - Jan Seuntjens
- Medical Physics Unit McGill University Montréal QCH3A 0G4Canada
| | - Karen E. Christaki
- Dosimetry and Medical Radiation Physics Section International Atomic Energy Agency A‐1400Vienna Austria
| | - Ahmed Meghzifene
- Dosimetry and Medical Radiation Physics Section International Atomic Energy Agency A‐1400Vienna Austria
| |
Collapse
|
6
|
Howitz S, Schwedas M, Wiezorek T, Zink K. Experimental and Monte Carlo-based determination of the beam quality specifier for TomoTherapyHD treatment units. Z Med Phys 2017; 28:142-149. [PMID: 29031915 DOI: 10.1016/j.zemedi.2017.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 08/08/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
Reference dosimetry by means of clinical linear accelerators in high-energy photon fields requires the determination of the beam quality specifier TPR20,10, which characterizes the relative particle flux density of the photon beam. The measurement of TPR20,10 has to be performed in homogenous photon beams of size 10×10cm2 with a focus-detector distance of 100cm. These requirements cannot be fulfilled by TomoTherapy treatment units from Accuray. The TomoTherapy unit provides a flattening-filter-free photon fan beam with a maximum field width of 40cm and field lengths of 1.0cm, 2.5cm and 5.0cm at a focus-isocenter distance of 85cm. For the determination of the beam quality specifier from measurements under nonstandard reference conditions Sauer and Palmans proposed experiment-based fit functions. Moreover, Sauer recommends considering the impact of the flattening-filter-free beam on the measured data. To verify these fit functions, in the present study a Monte Carlo based model of the treatment head of a TomoTherapyHD unit was designed and commissioned with existing beam data of our clinical TomoTherapy machine. Depth dose curves and dose profiles were in agreement within 1.5% between experimental and Monte Carlo-based data. Based on the fit functions from Sauer and Palmans the beam quality specifier TPR20,10 was determined from field sizes 5×5cm2, 10×5cm2, 20×5cm2 and 40×5cm2 based on dosimetric measurements and Monte Carlo simulations. The mean value from all experimental values of TPR20,10 resulted in TPR20,10¯=0.635±0.4%. The impact of the non-homogenous field due to the flattening-filter-free beam was negligible for field sizes below 20×5cm2. The beam quality specifier calculated by Monte Carlo simulations was TPR20,10=0.628 and TPR20,10=0.631 for two different calculation methods. The stopping power ratio water-to-air sw,aΔ directly depends on the beam quality specifier. The value determined from all experimental TPR20,10 data was sw,aΔ=1.126±0.1%, which is in excellent agreement with the value directly calculated by Monte Carlo simulations. The agreement is a good indication that the equations proposed by Sauer and Palmans are able to calculate the beam quality specifier under reference conditions from measurements in arbitrary photon field sizes with high accuracy and are applicable for the TomoTherapyHD treatment unit.
Collapse
Affiliation(s)
- Simon Howitz
- University Hospital Jena, Department of Radiation Oncology, Germany; Institute for Medical Physics and Radiation Protection IMPS, University of Applied Science - THM, Giessen, Germany; Philipps-University, Marburg, Germany.
| | - Michael Schwedas
- University Hospital Jena, Department of Radiation Oncology, Germany
| | - Tilo Wiezorek
- University Hospital Jena, Department of Radiation Oncology, Germany
| | - Klemens Zink
- Institute for Medical Physics and Radiation Protection IMPS, University of Applied Science - THM, Giessen, Germany; University Medical Center Giessen-Marburg, Department of Radiation Oncology, Germany; Frankfurt Institute for Advanced Studies (FIAS), Frankfurt, Germany
| |
Collapse
|
7
|
Lechner W, Kuess P, Georg D, Palmans H. Equivalent (uniform) square field sizes of flattening filter free photon beams. ACTA ACUST UNITED AC 2017; 62:7694-7713. [DOI: 10.1088/1361-6560/aa83f5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
8
|
Design and implementation of a "cheese" phantom-based Tomotherapy TLD dose intercomparison. Strahlenther Onkol 2015; 191:855-61. [PMID: 26087907 DOI: 10.1007/s00066-015-0850-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND The unique beam-delivery technique of Tomotherapy machines (Accuray Inc., Sunnyvale, Calif.) necessitates tailored quality assurance. This requirement also applies to external dose intercomparisons. Therefore, the aim of the 2014 SSRMP (Swiss Society of Radiobiology and Medical Physics) dosimetry intercomparison was to compare two set-ups with different phantoms. MATERIALS AND METHODS A small cylindrical Perspex phantom, which is similar to the IROC phantom (Imaging and Radiation Oncology Core, Houston, Tex.), and the "cheese" phantom, which is provided by the Tomotherapy manufacturer to all institutions, were used. The standard calibration plans for the TomoHelical and TomoDirect irradiation techniques were applied. These plans are routinely used for dose output calibration in Tomotherapy institutions. We tested 20 Tomotherapy machines in Germany and Switzerland. The ratio of the measured (Dm) to the calculated (Dc) dose was assessed for both phantoms and irradiation techniques. The Dm/Dc distributions were determined to compare the suitability of the measurement set-ups investigated. RESULTS The standard deviations of the TLD-measured (thermoluminescent dosimetry) Dm/Dc ratios for the "cheese" phantom were 1.9 % for the TomoHelical (19 measurements) and 1.2 % (11 measurements) for the TomoDirect irradiation techniques. The corresponding ratios for the Perspex phantom were 2.8 % (18 measurements) and 1.8 % (11 measurements). CONCLUSION Compared with the Perspex phantom-based set-up, the "cheese" phantom-based set-up without individual planning was demonstrated to be more suitable for Tomotherapy dose checks. Future SSRMP dosimetry intercomparisons for Tomotherapy machines will therefore be based on the "cheese" phantom set-up.
Collapse
|
9
|
Van Gestel D, Van den Weyngaert D, De Kerf G, De Ost B, Vanderveken O, Van Laer C, Specenier P, Geussens Y, Wouters K, Meulemans E, Cheung KJ, Grégoire V, Vermorken JB. Helical tomotherapy in head and neck cancer: a European single-center experience. Oncologist 2015; 20:279-90. [PMID: 25673104 PMCID: PMC4350799 DOI: 10.1634/theoncologist.2014-0337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/18/2014] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND We report on a retrospective analysis of 147 patients with early and locoregionally advanced squamous cell head and neck cancer (SCCHN) treated with helical tomotherapy (HT). PATIENTS AND METHODS Included were patients with SCCHN of the oral cavity (OC), oropharynx (OP), hypopharynx (HP), or larynx (L) consecutively treated in one radiotherapy center in 2008 and 2009. The prescribed HT dose was 60-66 Gy in the postoperative setting (group A) and 66-70 Gy when given as primary treatment (group B). HT was given alone, concurrent with systemic therapy (ST), that is, chemotherapy, biotherapy, or both, and with or without induction therapy (IT). Acute and late toxicities are reported using standard criteria; locoregional failure/progression (LRF), distant metastases (DM), and second primary tumors (SPT) were documented, and event-free survival (EFS) and overall survival (OS) were calculated from the start of HT. RESULTS Group A patients received HT alone in 22 cases and HT + ST in 20 cases; group B patients received HT alone in 17 cases and HT + ST in 88 cases. Severe (grade ≥ 3) acute mucosal toxicity and swallowing problems increased with more additional ST. After a median follow-up of 44 months, grade ≥2 late toxicity after HT + ST was approximately twice that of HT alone for skin, subcutis, pharynx, and larynx. Forty percent had grade ≥2 late xerostomia, and 29% had mucosal toxicity. At 3 years, LRF/DM/SPT occurred in 7%/7%/17% and 25%/13%/5% in groups A and B, respectively, leading to a 3-year EFS/OS of 64%/74% and 56%/63% in groups A and B, respectively. CONCLUSION The use of HT alone or in combination with ST is feasible and promising and has a low late fatality rate. However, late toxicity is nearly twice as high when ST is added to HT.
Collapse
Affiliation(s)
- Dirk Van Gestel
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Danielle Van den Weyngaert
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Geert De Kerf
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Bie De Ost
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Olivier Vanderveken
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Carl Van Laer
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Pol Specenier
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Yasmyne Geussens
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Kristien Wouters
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Els Meulemans
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Kin Jip Cheung
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Vincent Grégoire
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| | - Jan B Vermorken
- Department of Radiotherapy, University Radiotherapy Antwerp UZA/ZNA, Antwerp, Belgium; Department of Otolaryngology and Head and Neck Surgery, Department of Medical Oncology, Scientific Coordination and Biostatistics, and Data-Management Multidisciplinair Oncologisch Centrum Antwerpen, Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Iridium Kankernetwerk, Campus Nikolaas, Sint Niklaas, Belgium; Radiation Oncology Department and Centre for Molecular Imaging and Experimental Radiotherapy, St-Luc University Hospital, Brussels, Belgium
| |
Collapse
|
10
|
Thomas SJ, Aspradakis MM, Byrne JP, Chalmers G, Duane S, Rogers J, Thomas RAS, Tudor GSJ, Twyman N. Reference dosimetry on TomoTherapy: an addendum to the 1990 UK MV dosimetry code of practice. Phys Med Biol 2014; 59:1339-52. [DOI: 10.1088/0031-9155/59/6/1339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
11
|
Palmans H. Determination of the beam quality index of high-energy photon beams under nonstandard reference conditions. Med Phys 2012; 39:5513-9. [DOI: 10.1118/1.4745565] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
12
|
Sterpin E, Mackie TR, Vynckier S. Monte Carlo computed machine-specific correction factors for reference dosimetry of TomoTherapy static beam for several ion chambers. Med Phys 2012; 39:4066-72. [DOI: 10.1118/1.4722752] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
13
|
Gago-Arias A, Rodríguez-Romero R, Sánchez-Rubio P, Miguel González-Castaño D, Gómez F, Núñez L, Palmans H, Sharpe P, Pardo-Montero J. Correction factors for A1SL ionization chamber dosimetry in TomoTherapy: Machine-specific, plan-class, and clinical fields. Med Phys 2012; 39:1964-70. [DOI: 10.1118/1.3692181] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
14
|
De Ost B, Schaeken B, Vynckier S, Sterpin E, Van den Weyngaert D. Reference dosimetry for helical tomotherapy: Practical implementation and a multicenter validation. Med Phys 2011; 38:6020-6. [DOI: 10.1118/1.3651496] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
|
15
|
Zeverino M, Agostinelli S, Pupillo F, Taccini G. Determination of the correction factors for different ionization chambers used for the calibration of the helical tomotherapy static beam. Radiother Oncol 2011; 100:424-8. [DOI: 10.1016/j.radonc.2011.08.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 08/26/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
|
16
|
Georg D, Knöös T, McClean B. Current status and future perspective of flattening filter free photon beams. Med Phys 2011; 38:1280-93. [PMID: 21520840 DOI: 10.1118/1.3554643] [Citation(s) in RCA: 218] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Flattening filters (FFs) have been considered as an integral part of the treatment head of a medical accelerator for more than 50 years. The reasons for the longstanding use are, however, historical ones. Advanced treatment techniques, such as stereotactic radiotherapy or intensity modulated radiotherapy have stimulated the interest in operating linear accelerators in a flattening filter free (FFF) mode. The current manuscript reviews treatment head physics of FFF beams, describes their characteristics and the resulting potential advantages in their medical use, and closes with an outlook. METHODS A number of dosimetric benefits have been determined for FFF beams, which range from increased dose rate and dose per pulse to favorable output ratio in-air variation with field size, reduced energy variation across the beam, and reduced leakage and out-of-field dose, respectively. Finally, the softer photon spectrum of unflattened beams has implications on imaging strategies and radiation protection. RESULTS The dosimetric characteristics of FFF beams have an effect on treatment delivery, patient comfort, dose calculation accuracy, beam matching, absorbed dose determination, treatment planning, machine specific quality assurance, imaging, and radiation protection. When considering conventional C-arm linacs in a FFF mode, more studies are needed to specify and quantify the clinical advantages, especially with respect to treatment plan quality and quality assurance. CONCLUSIONS New treatment units are already on the market that operate without a FF or can be operated in a dedicated clinical FFF mode. Due to the convincing arguments of removing the FF, it is expected that more vendors will offer dedicated treatment units for advanced photon beam therapy in the near future. Several aspects related to standardization, dosimetry, treatment planning, and optimization need to be addressed in more detail in order to facilitate the clinical implementation of unflattened beams.
Collapse
Affiliation(s)
- Dietmar Georg
- Department of Radiotherapy, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, A-1090 Vienna, Austria.
| | | | | |
Collapse
|
17
|
Perichon N, Garcia T, François P, Lourenço V, Lesven C, Bordy JM. Calibration of helical tomotherapy machine using EPR/alanine dosimetry. Med Phys 2011; 38:1168-77. [DOI: 10.1118/1.3553407] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
18
|
Langen KM, Papanikolaou N, Balog J, Crilly R, Followill D, Goddu SM, Grant W, Olivera G, Ramsey CR, Shi C. QA for helical tomotherapy: Report of the AAPM Task Group 148a). Med Phys 2010; 37:4817-53. [DOI: 10.1118/1.3462971] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
|
19
|
Ceberg C, Johnsson S, Lind M, Knöös T. Prediction of stopping-power ratios in flattening-filter free beams. Med Phys 2010; 37:1164-8. [PMID: 20384253 DOI: 10.1118/1.3314074] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE In recent years, there has been an increasing interest in flattening-filter free (FFF) beams. However, since the removal of the flattening filter will affect both the mean and the variance of the energy spectrum, current beam-quality specifiers may not be adequate for reference dosimetry in such beams. The purpose of this work was to investigate an alternative, more general beam-quality specifier. METHODS The beam-quality specifier used in this work was a combination of the kerma-weighted mean and the coefficient of variation of the linear attenuation coefficient in water. These parameters can in theory be determined from narrow-beam transmission measurements using a miniphantom "in-air," which is a measurement condition well suited also to small and nonstandard fields. The relation between the Spencer-Attix stopping-power ratios and this novel beam-quality specifier was described by a simple polynomial. For reference, the authors used Monte Carlo calculated spectra and stopping-power data for nine different beams, with and without flattening filter. RESULTS The polynomial coefficients were obtained by least-squares optimization. For all beams included in this investigation, the average of the differences between the predicted and the Monte Carlo calculated stopping-power ratios was 0.02 +/- 0.17% (1 SD) (including TomoTherapy and CyberKnife example beams). CONCLUSIONS An alternative dual-parameter beam-quality specifier was investigated. The evaluation suggests that it can be used successfully to predict stopping-power ratios in FFF as well as conventional beams, regardless of filtration.
Collapse
Affiliation(s)
- Crister Ceberg
- Department of Medical Radiation Physics, Lund University, Box 117, SE-221 00 Lund, Sweden.
| | | | | | | |
Collapse
|
20
|
Practical Aspects of Implementation of Helical Tomotherapy for Intensity-modulated and Image-guided Radiotherapy. Clin Oncol (R Coll Radiol) 2010; 22:294-312. [DOI: 10.1016/j.clon.2010.02.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 01/13/2010] [Accepted: 02/09/2010] [Indexed: 12/31/2022]
|
21
|
Sauer OA. Determination of the quality index (Q) for photon beams at arbitrary field sizes. Med Phys 2009; 36:4168-72. [DOI: 10.1118/1.3197062] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
22
|
Bailat CJ, Buchillier T, Pachoud M, Moeckli R, Bochud FO. An absolute dose determination of helical tomotherapy accelerator, TomoTherapy High-Art II. Med Phys 2009; 36:3891-6. [DOI: 10.1118/1.3176951] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
23
|
Zhao YL, Mackenzie M, Kirkby C, Fallone BG. Monte Carlo evaluation of a treatment planning system for helical tomotherapy in an anthropomorphic heterogeneous phantom and for clinical treatment plans. Med Phys 2008; 35:5366-74. [DOI: 10.1118/1.3002316] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
24
|
Zhao YL, Mackenzie M, Kirkby C, Fallone BG. Monte Carlo calculation of helical tomotherapy dose delivery. Med Phys 2008; 35:3491-500. [PMID: 18777909 DOI: 10.1118/1.2948409] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Helical tomotherapy delivers intensity modulated radiation therapy using a binary multileaf collimator (MLC) to modulate a fan beam of radiation. This delivery occurs while the linac gantry and treatment couch are both in constant motion, so the beam describes, from a patient/phantom perspective, a spiral or helix of dose. The planning system models this continuous delivery as a large number (51) of discrete gantry positions per rotation, and given the small jaw/fan width setting typically used (1 or 2.5 cm) and the number of overlapping rotations used to cover the target (pitch often <0.5), the treatment planning system (TPS) potentially employs a very large number of static beam directions and leaf opening configurations to model the modulated fields. All dose calculations performed by the system employ a convolution/superposition model. In this work the authors perform a full Monte Carlo (MC) dose calculation of tomotherapy deliveries to phantom computed tomography (CT) data sets to verify the TPS calculations. All MC calculations are performed with the EGSnrc-based MC simulation codes, BEAMnrc and DOSXYZnrc. Simulations are performed by taking the sinogram (leaf opening versus time) of the treatment plan and decomposing it into 51 different projections per rotation, as does the TPS, each of which is segmented further into multiple MLC opening configurations, each with different weights that correspond to leaf opening times. Then the projection is simulated by the summing of all of the opening configurations, and the overall rotational treatment is simulated by the summing of all of the projection simulations. Commissioning of the source model was verified by comparing measured and simulated values for the percent depth dose and beam profiles shapes for various jaw settings. The accuracy of the MLC leaf width and tongue and groove spacing were verified by comparing measured and simulated values for the MLC leakage and a picket fence pattern. The validated source and MLC configuration were then used to simulate a complex modulated delivery from fixed gantry angle. Further, a preliminary rotational treatment plan to a delivery quality assurance phantom (the "cheese" phantom) CT data set was simulated. Simulations were compared with measured results taken with an A1SL ionization chamber or EDR2 film measurements in a water tank or in a solid water phantom, respectively. The source and MLC MC simulations agree with the film measurements, with an acceptable number of pixels passing the 2%/1 mm gamma criterion. 99.8% of voxels of the MC calculation in the planning target volume (PTV) of the preliminary plan passed the 2%/2 mm gamma value test. 87.0% and 66.2% of the voxels in two organs at risk (OARs) passed the 2%/2 mm tests. For a 3%/3 mm criterion, the PTV and OARs show 100%, 93.2%, and 86.6% agreement, respectively. All voxels passed the gamma value test with a criterion of 5%/3 mm. The Tomo-Therapy TPS showed comparable results.
Collapse
Affiliation(s)
- Ying-Li Zhao
- Department of Medical Physics, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | | | | | | |
Collapse
|
25
|
Alfonso R, Andreo P, Capote R, Huq MS, Kilby W, Kjäll P, Mackie TR, Palmans H, Rosser K, Seuntjens J, Ullrich W, Vatnitsky S. A new formalism for reference dosimetry of small and nonstandard fields. Med Phys 2008; 35:5179-86. [DOI: 10.1118/1.3005481] [Citation(s) in RCA: 415] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
|
26
|
Muzik J, Soukup M, Alber M. Comparison of fixed-beam IMRT, helical tomotherapy, and IMPT for selected cases. Med Phys 2008; 35:1580-92. [PMID: 18491552 DOI: 10.1118/1.2890085] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A growing number of advanced intensity modulated treatment techniques is becoming available. In this study, the specific strengths and weaknesses of four techniques, static and dynamic multileaf collimator (MLC), conventional linac-based IMRT, helical tomotherapy (HT), and spot-scanning proton therapy (IMPT) are investigated in the framework of biological, EUD-based dose optimization. All techniques were implemented in the same in-house dose optimization tool. Monte Carlo dose computation was used in all cases. All dose-limiting, normal tissue objectives were treated as hard constraints so as to facilitate comparability. Five patient cases were selected to offer each technique a chance to show its strengths: a deep-seated prostate case (for 15 MV linac-based IMRT), a pediatric case (for IMPT), an extensive head-and-neck case (for HT), a lung tumor (for HT), and an optical neurinoma (for noncoplanar linac-based IMRT with a miniMLC). The plans were compared by dose statistics and equivalent uniform dose metrics. All techniques delivered results that were comparable with respect to target coverage and the most dose-limiting normal tissues. Static MLC IMRT struggled to achieve sufficient target coverage at the same level of dose homogeneity in the lung case. IMPT gained the greatest advantage when lung sparing was important, but did not significantly reduce the risk of nearby organs. Tomotherapy and dynamic MLC IMRT showed mostly the same performance. Despite the apparent conceptual differences, all four techniques fare equally well for standard patient cases. The absence of relevant differences is in part due to biological optimization, which offers more freedom to shape the dose than do, e.g., dose volume histogram constraints. Each technique excels for certain classes of highly complex cases, and hence the various modalities should be viewed as complementary, rather than competing.
Collapse
Affiliation(s)
- Jan Muzik
- Abteilung für Medizinische Physik, Universitätsklinikum Tübingen, Tübingen, Germany.
| | | | | |
Collapse
|
27
|
Xiong G, Rogers DWO. Relationship between %dd(10)x and stopping-power ratios for flattening filter free accelerators: A Monte Carlo study. Med Phys 2008; 35:2104-9. [DOI: 10.1118/1.2905028] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
28
|
Broggi S, Mauro Cattaneo G, Molinelli S, Maggiulli E, Del Vecchio A, Longobardi B, Perna L, Fazio F, Calandrino R. Results of a two-year quality control program for a helical tomotherapy unit. Radiother Oncol 2008; 86:231-41. [DOI: 10.1016/j.radonc.2007.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 10/31/2007] [Accepted: 11/02/2007] [Indexed: 10/22/2022]
|
29
|
Dose painting with IMPT, helical tomotherapy and IMXT: A dosimetric comparison. Radiother Oncol 2008; 86:30-4. [PMID: 18061294 DOI: 10.1016/j.radonc.2007.11.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 10/31/2007] [Accepted: 11/02/2007] [Indexed: 11/21/2022]
|
30
|
Achterberg N, Müller RG. Multibeam tomotherapy: a new treatment unit devised for multileaf collimation, intensity-modulated radiation therapy. Med Phys 2007; 34:3926-42. [PMID: 17985638 DOI: 10.1118/1.2779129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A fully integrated system for treatment planning, application, and verification for automated multileaf collimator (MLC) based, intensity-modulated, image-guided, and adaptive radiation therapy (IMRT, IGRT and ART, respectively) is proposed. Patient comfort, which was the major development goal, will be achieved through a new unit design and short treatment times. Our device for photon beam therapy will consist of a new dual energy linac with five fixed treatment heads positioned evenly along one plane but one electron beam generator only. A minimum of moving parts increases technical reliability and reduces motion times to a minimum. Motion is allowed solely for the MLCs, the robotic patient table, and the small angle gantry rotation of +/- 36 degrees. Besides sophisticated electron beam guidance, this compact setup can be built using existing modules. The flattening-filter-free treatment heads are characterized by reduced beam-on time and contain apertures restricted in one dimension to the area of maximum primary fluence output. In the case of longer targets, this leads to a topographic intensity modulation, thanks to the combination of "step and shoot" MLC delivery and discrete patient couch motion. Owing to the limited number of beam directions, this multislice cone beam serial tomotherapy is referred to as "multibeam tomotherapy." Every patient slice is irradiated by one treatment head at any given moment but for one subfield only. The electron beam is then guided to the next head ready for delivery, while the other heads are preparing their leaves for the next segment. The "Multifocal MLC-positioning" algorithm was programmed to enable treatment planning and optimize treatment time. We developed an overlap strategy for the longitudinally adjacent fields of every beam direction, in doing so minimizing the field match problem and the effects of possible table step errors. Clinical case studies show for the same or better planning target volume coverage, better organ-at-risk sparing, and comparable mean integral dose to the normal tissue a reduction in treatment time by more than 50% to only a few minutes in comparison to high-quality 3-D conformal and IMRT treatments. As a result, it will be possible to incorporate features for better patient positioning and image guidance, while sustaining reasonable overall treatment times at the same time. The virtual multibeam tomotherapy design study TOM'5-CT contains a dedicated electron beam CT (TOM'AGE) and an objective optical topometric patient positioning system (TOPOS). Thanks to the wide gantry bore of 120 cm and slim gantry depths of 70 cm, patients can be treated very comfortably, in all cases tumor-isocentrically, as well as with noncoplanar beam arrangements as in stereotactic radiosurgery with a couch rotation of up to +/- 54 degrees. The TOM'5 treatment unit on which this theoretical concept is based has a stand-alone depth of 40 cm and an outer diameter of 245 cm; the focus-isocenter distance of the heads is 100 cm with a field size of 40 cm x 7 cm and 0.5 cm leaves, which operate perpendicular to the axis of table motion.
Collapse
Affiliation(s)
- Nils Achterberg
- Strahlenklinik, Universitätsklinikum Erlangen, Universitätstrasse 27, 91054 Erlangen, Germany.
| | | |
Collapse
|
31
|
Abstract
Tomotherapy is the delivery of intensity modulated radiation therapy using rotational delivery of a fan beam in the manner of a CT scanner. In helical tomotherapy the couch and gantry are in continuous motion akin to a helical CT scanner. Helical tomotherapy is inherently capable of acquiring CT images of the patient in treatment position and using this information for image guidance. This review documents technological advancements of the field concentrating on the conceptual beginnings through to its first clinical implementation. The history of helical tomotherapy is also a story of technology migration from academic research to a university-industrial partnership, and finally to commercialization and widespread clinical use.
Collapse
MESH Headings
- Equipment Design
- History, 20th Century
- History, 21st Century
- Radiotherapy Planning, Computer-Assisted/history
- Radiotherapy Planning, Computer-Assisted/instrumentation
- Radiotherapy Planning, Computer-Assisted/methods
- Radiotherapy, Conformal/history
- Radiotherapy, Conformal/instrumentation
- Radiotherapy, Conformal/methods
- Tomography, X-Ray Computed/history
- Tomography, X-Ray Computed/instrumentation
- Tomography, X-Ray Computed/methods
Collapse
Affiliation(s)
- T R Mackie
- University of Wisconsin, Madison, WI 53706, USA.
| |
Collapse
|
32
|
Thomas SD, Mackenzie M, Field GC, Syme AM, Fallone BG. Patient specific treatment verifications for helical tomotherapy treatment plans. Med Phys 2006; 32:3793-800. [PMID: 16475779 DOI: 10.1118/1.2134929] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We performed two-dimensional treatment verifications for ten patients planned and treated with helical tomotherapy. The treatment verification consisted of a film measurement as well as point dose measurements made with an ion chamber. The agreement between the calculated and the measured film dose distributions was evaluated with the gamma index calculated for three sets of criteria (2 mm and 2%, 4 mm and 3%, and 3 mm and 5%) as recommended in the literature. Good agreement was found between measured and calculated distributions without any need of normalization of the dose data but with dose map registration using reference marks. In this case, 69.8 +/- 17.2%, 92.6 +/- 9.0%, and 93.4 +/- 8.5% passed the 2 mm and 2%, 4 mm and 3%, and 3 mm and 5% criteria, respectively. Agreement was excellent when both normalization and manual registration of the dose maps was employed. In this case 91.2 +/- 5.6%, 99.0 +/- 1.4%, and 99.5 +/- 0.8% passed the 2 mm and 2%, 4 mm and 3%, and 3 mm and 5% criteria, respectively. The mean percent discrepancy for the point dose measurements was -0.5 +/- 1.1%, -2.4 +/- 3.7%, -1.1 +/- 7.3% for the high dose, low dose, and critical structure point, respectively. Three criteria for a satisfactory treatment verification in the high dose regions of a plan were established. For the un-normalized reference mark registered data 80% of pixels must pass the 3 mm and 5% criteria. For the normalized and manually registered data, 80% must pass the 2 mm and 2% criteria, and the point dose measurement must be within 2% of the calculated dose. All low dose region/critical structure point dose measurements were evaluated on a patient by patient basis. The criteria we recommend can be useful for the routine evaluation of treatment plans for tomotherapy systems.
Collapse
Affiliation(s)
- S D Thomas
- Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada
| | | | | | | | | |
Collapse
|