|
1
|
Wahabi JM, Wong JHD, Mahdiraji GA, Ung NM. Feasibility of determining external beam radiotherapy dose using LuSy dosimeter. J Appl Clin Med Phys 2024; 25:e14387. [PMID: 38778567 PMCID: PMC11163501 DOI: 10.1002/acm2.14387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 04/20/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
INTRODUCTION Radiation dose measurement is an essential part of radiotherapy to verify the correct delivery of doses to patients and ensure patient safety. Recent advancements in radiotherapy technology have highlighted the need for fast and precise dosimeters. Technologies like FLASH radiotherapy and magnetic-resonance linear accelerators (MR-LINAC) demand dosimeters that can meet their unique requirements. One promising solution is the plastic scintillator-based dosimeter with high spatial resolution and real-time dose output. This study explores the feasibility of using the LuSy dosimeter, an in-house developed plastic scintillator dosimeter for dose verification across various radiotherapy techniques, including conformal radiotherapy (CRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS). MATERIALS AND METHODS A new dosimetry system, comprising a new plastic scintillator as the sensing material, was developed and characterized for radiotherapy beams. Treatment plans were created for conformal radiotherapy, IMRT, VMAT, and SRS and delivered to a phantom. LuSy dosimeter was used to measure the delivered dose for each plan on the surface of the phantom and inside the target volumes. Then, LuSy measurements were compared against an ionization chamber, MOSFET dosimeter, radiochromic films, and dose calculated using the treatment planning system (TPS). RESULTS For CRT, surface dose measurement by LuSy dosimeter showed a deviation of -5.5% and -5.4% for breast and abdomen treatment from the TPS, respectively. When measuring inside the target volume for IMRT, VMAT, and SRS, the LuSy dosimeter produced a mean deviation of -3.0% from the TPS. Surface dose measurement resulted in higher TPS discrepancies where the deviations for IMRT, VMAT, and SRS were -2.0%, -19.5%, and 16.1%, respectively. CONCLUSION The LuSy dosimeter was feasible for measuring radiotherapy doses for various treatment techniques. Treatment delivery verification enables early error detection, allowing for safe treatment delivery for radiotherapy patients.
Collapse
Affiliation(s)
- Janatul Madinah Wahabi
- Department of Biomedical ImagingFaculty of MedicineUniversiti MalayaKuala LumpurMalaysia
- Radiotherapy and Oncology DepartmentNational Cancer InstitutePutrajayaMalaysia
| | - Jeannie Hsiu Ding Wong
- Department of Biomedical ImagingFaculty of MedicineUniversiti MalayaKuala LumpurMalaysia
- Universiti Malaya Research Imaging Centre (UMRIC), Faculty of MedicineUniversiti MalayaKuala LumpurMalaysia
| | | | - Ngie Min Ung
- Clinical Oncology UnitFaculty of MedicineUniversiti MalayaKuala LumpurMalaysia
| |
Collapse
|
|
2
|
Wahabi JM, Ung NM, Mahdiraji GA, Wong JHD. Development and characterisation of a plastic scintillator dosemeter in high-energy photon beams. RADIATION PROTECTION DOSIMETRY 2024; 200:264-273. [PMID: 38123475 DOI: 10.1093/rpd/ncad303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 10/22/2023] [Accepted: 11/15/2023] [Indexed: 12/23/2023]
Abstract
The radioluminescent (RL) dosemeter is excellent for real-time radiation measurement and can be used in various applications. A plastic scintillator is often the choice sensor because of its size and tissue equivalency. This study aims to characterise a novel plastic scintillator irradiated with high-energy photon beams. An RL dosimetry system was developed using the plastic scintillator. The RL dosimetry system was irradiated using a linear accelerator to characterise the dose linearity, dose rate, energy dependency and depth dose. The developed system showed a linear response toward the dose and dose rate. An energy dependency factor of 1.06 was observed. Depth dose measurement showed a mean deviation of 1.21% from the treatment planning system. The response and characteristics of the plastic scintillator show that it may be used as an alternative in an RL dosimetry system.
Collapse
Affiliation(s)
- Janatul M Wahabi
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
- Ministry of Health Malaysia, Putrajaya 62590, Malaysia
| | - N M Ung
- Clinical Oncology Unit, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | | | - Jeannie H D Wong
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| |
Collapse
|
|
3
|
Yada R, Maenaka K, Miyamoto S, Okada G, Sasakura A, Ashida M, Adachi M, Sato T, Wang T, Akasaka H, Mukumoto N, Shimizu Y, Sasaki R. Real-time in vivo dosimetry system based on an optical fiber-coupled microsized photostimulable phosphor for stereotactic body radiation therapy. Med Phys 2020; 47:5235-5249. [PMID: 32654194 DOI: 10.1002/mp.14383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 06/21/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022] Open
Abstract
PURPOSE To develop an in vivo dosimeter system for stereotactic body radiation therapy (SBRT) that can perform accurate and precise real-time measurements, using a microsized amount of a photostimulable phosphor (PSP), BaFBr:Eu2+ . METHODS The sensitive volume of the PSP was 1.26 × 10-5 cm3 . The dosimeter system was designed to apply photostimulation to the PSP after the decay of noise signals, in synchronization with the photon beam pulse of a linear accelerator (LINAC), to eliminate the noise signals completely using a time separation technique. The noise signals included stem signals, and radioluminescence signals generated by the PSP. In addition, the dosimeter system was built on a storage-type dosimeter that could read out a signal after an arbitrary preset number of photon beam pulses were incident. First, the noise and photostimulated luminescence (PSL) signal decay times were measured. Subsequently, we confirmed that the PSL signals could be exclusively read out within the photon beam pulse interval. Finally, using a water phantom, the basic characteristics of the dosimeter system were demonstrated under SBRT conditions, and the feasibility for clinical application was investigated. The reproducibility, dose linearity, dose-rate dependence, temperature dependence, and angular dependence were evaluated. The feasibility was confirmed by measurements at various dose gradients and using a representative treatment plan for a metastatic liver tumor. A clinical plan was created with a two-arc beam volumetric modulated arc therapy using a 10 MV flattening filter-free photon beam. For the water phantom measurements, the clinical plan was compiled into a plan with a fixed gantry angle of 0°. To evaluate the energy dependence during SBRT, the percent depth dose (PDD) was measured and compared with those calculated via Monte Carlo (MC) simulations. RESULTS All the PSL signals could be read out while eliminating the noise signals within the minimum pulse interval of the LINAC. Stable real-time measurements could be performed with a time resolution of 56 ms (i.e., number of pulses = 20). The dose linearity was good in the dose range of 0.01-100 Gy. The measurements agreed within 1% at dose rates of 40-2400 cGy/min. The temperature and angular dependence were also acceptable since these dependencies had only a negligible effect on the measurements in SBRT. At a dose gradient of 2.21 Gy/mm, the measured dose agreed with that calculated using a treatment planning system (TPS) within the measurement uncertainties due to the probe position. For measurements using a representative treatment plan, the measured dose agreed with that calculated using the TPS within 0.5% at the center of the beam axis. The PDD measurements agreed with the MC calculations to within 1% for field sizes <5 × 5 cm2 . CONCLUSION The in vivo dosimeter system developed using BaFBr:Eu2+ is capable of real-time, accurate, and precise measurement under SBRT conditions. The probe is smaller than a conventional dosimeter, has excellent spatial resolution, and can be valuable in SBRT with a steep dose distribution over a small field. The developed PSP dosimeter system appears to be suitable for in vivo SBRT dosimetry.
Collapse
Affiliation(s)
- Ryuichi Yada
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Kazusuke Maenaka
- Department of Electrical Engineering and Computer Science, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan
| | - Shuji Miyamoto
- Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigoricho, Akogun, Hyogo, 678-1205, Japan
| | - Go Okada
- Co-creative Research Center of Industrial Science and Technology, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa, 924-0838, Japan
| | - Aki Sasakura
- Meisyo Kiko Co., Ltd, 148 Numa, Hikamicho, Tamba, Hyogo, 669-3634, Japan
| | - Motoi Ashida
- Meisyo Kiko Co., Ltd, 148 Numa, Hikamicho, Tamba, Hyogo, 669-3634, Japan
| | - Masashi Adachi
- Meisyo Kiko Co., Ltd, 148 Numa, Hikamicho, Tamba, Hyogo, 669-3634, Japan
| | - Tatsuhiko Sato
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Tianyuan Wang
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Hiroaki Akasaka
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Naritoshi Mukumoto
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Yasuyuki Shimizu
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Ryohei Sasaki
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| |
Collapse
|
|
4
|
Famulari G, Linares Rosales HM, Dupere J, Medich DC, Beaulieu L, Enger SA. Monte Carlo dosimetric characterization of a new high dose rate 169 Yb brachytherapy source and independent verification using a multipoint plastic scintillator detector. Med Phys 2020; 47:4563-4573. [PMID: 32686145 DOI: 10.1002/mp.14336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/02/2020] [Accepted: 06/08/2020] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A prototype 169 Yb source was developed in combination with a dynamic rotating platinum shield system (AIM-Brachy) to deliver intensity modulated brachytherapy (IMBT). The purpose of this study was to evaluate the dosimetric characteristics of the bare/shielded 169 Yb source using Monte Carlo (MC) simulations and perform an independent dose verification using a dosimetry platform based on a multipoint plastic scintillator detector (mPSD). METHODS The TG-43U1 dosimetric parameters were calculated for the source model using RapidBrachyMCTPS. Real-time dose rate measurements were performed in a water tank for both the bare/shielded source using a custom remote afterloader. For each dwell position, the dose rate was independently measured by the three scintillators (BCF-10, BCF-12, and BCF-60). For the bare source, dose rate was measured at distances up to 3 cm away from the source over a range of 7 cm along the catheter. For the shielded source, measurements were performed with the mPSD placed at 1 cm from the source at four different azimuthal angles ( 0 ∘ , 9 0 ∘ , 18 0 ∘ , and 27 0 ∘ ). RESULTS The dosimetric parameters were tabulated for the source model. For the bare source, differences between measured and calculated along-away dose rates were generally below 5-10%. Along the transverse axis, deviations were, on average (range), 3.3% (0.6-6.2%) for BCF-10, 1.7% (0.9-2.9%) for BCF-12, and 2.2% (0.3-4.4%) for BCF-60. The maximum dose rate reduction due to shielding at a radial distance of 1 cm was 88.8 ± 1.2%, compared to 83.5 ± 0.5% as calculated by MC. CONCLUSIONS The dose distribution for the bare/shielded 169 Yb source was independently verified using mPSD with good agreement in regions close to the source. The 169 Yb source coupled with the partial-shielding system is an effective technique to deliver IMBT.
Collapse
Affiliation(s)
- Gabriel Famulari
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada
| | - Haydee M Linares Rosales
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, QC, G1R 2J6, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec-Université Laval, QC, G1R 2J6, Canada
| | - Justine Dupere
- Department of Physics, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - David C Medich
- Department of Physics, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Luc Beaulieu
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, QC, G1R 2J6, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec-Université Laval, QC, G1R 2J6, Canada
| | - Shirin A Enger
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada.,Department of Oncology, McGill University, Montreal, QC, H4A 3J1, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, H3H 2R9, Canada
| |
Collapse
|
|
5
|
Linares Rosales HM, Duguay-Drouin P, Archambault L, Beddar S, Beaulieu L. Optimization of a multipoint plastic scintillator dosimeter for high dose rate brachytherapy. Med Phys 2019; 46:2412-2421. [PMID: 30891803 DOI: 10.1002/mp.13498] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 01/16/2019] [Accepted: 02/18/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE This study is devoted to optimizing and characterizing the response of a multipoint plastic scintillator detector (mPSD) for application to in vivo dosimetry in high dose rate (HDR) brachytherapy. METHODS An exhaustive analysis was carried out in order to obtain an optimized mPSD design that maximizes the scintillation light collection produced by the interaction of ionizing photons. More than 20 prototypes of mPSD were built and tested in order to determine the appropriate order of scintillators relative to the photodetector (distal, center, or proximal) as well as their length as a function of the scintillation light emitted. The available detecting elements are the BCF-60, BCF-12, and BCF-10 scintillators (Saint Gobain Crystals, Hiram, OH, USA), separated from each other by segments of Eska GH-4001 clear optical fibers (Mitsubishi Rayon Co., Ltd., Tokyo, Japan). The contribution of each scintillator to the total spectrum was determined by irradiations in the low energy range (<120 keV). For the best mPSD design, a numerical optimization was done in order to select the optical components [dichroic mirrors, filters, and photomultipliers tubes (PMTs)] that best match the light emission profile. Calculations were performed taking into account the measured scintillation spectrum and light yield, the manufacturer-reported transmission and attenuation of the optical components, and the experimentally characterized PMT noise. The optimized dosimetric system was used for HDR brachytherapy measurements. The system was independently controlled from the 192 Ir source via LabVIEW and read simultaneously using an NI-DAQ board. Dose measurements as a function of distance from the source were carried out according to TG-43U1 recommendations. The system performance was quantified in terms of signal to noise ratio (SNR) and signal to background ratio (SBR). RESULTS For best overall light-yield emission, it was determined that BCF-60 should be placed at the distal position, BCF-12 in the center, and BCF-10 at the proximal position with respect to the photodetector. This configuration allowed for optimized light transmission through the collecting fiber and avoided inter-scintillator excitation and self-absorption effects. The optimal scintillator length found was of 3, 6, and 7 mm for BCF-10, BCF- 12, and BCF-60, respectively. The optimized luminescence system allowed for signal deconvolution using a multispectral approach, extracting the dose to each element while taking into account the Cerenkov stem effect. Differences between the mPSD measurements and TG-43U1 remain below 5% in the range of 0.5 to 6.5 cm from the source. The dosimetric system can properly differentiate the scintillation signal from the background for a wide range of dose rate conditions; the SNR was found to be above 5 for dose rates above 22 mGy/s while the minimum SBR measured was 1.8 at 6 mGy/s. CONCLUSION Based on the spectral response at different conditions, an mPSD was constructed and optimized for HDR brachytherapy dosimetry. It is sensitive enough to allow multiple simultaneous measurements over a clinically useful distance range, up to 6.5 cm from the source. This study constitutes a baseline for future applications enabling real-time dose measurements and source position reporting over a wide range of dose rate conditions.
Collapse
Affiliation(s)
- Haydee M Linares Rosales
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, Québec City, QC, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec - Université Laval, Québec City, QC, Canada
| | - Patricia Duguay-Drouin
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, Québec City, QC, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec - Université Laval, Québec City, QC, Canada
| | - Louis Archambault
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, Québec City, QC, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec - Université Laval, Québec City, QC, Canada
| | - Sam Beddar
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77003, USA
| | - Luc Beaulieu
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer, Université Laval, Québec City, QC, Canada.,Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, CHU de Québec - Université Laval, Québec City, QC, Canada
| |
Collapse
|
|
6
|
Jennings MW, Rutten TP, Ottaway DJ. Evaluation of the signal quality of an inexpensive CMOS camera towards imaging a high-resolution plastic scintillation detector array. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2017.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
|
7
|
Beaulieu L, Beddar S. Review of plastic and liquid scintillation dosimetry for photon, electron, and proton therapy. Phys Med Biol 2016; 61:R305-R343. [DOI: 10.1088/0031-9155/61/20/r305] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
|
8
|
Small field correction factors for the IBA Razor. Phys Med 2016; 32:1025-9. [DOI: 10.1016/j.ejmp.2016.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/09/2016] [Accepted: 07/07/2016] [Indexed: 11/17/2022] Open
|
|
9
|
Tyler MK, Liu PZY, Lee C, McKenzie DR, Suchowerska N. Small field detector correction factors: effects of the flattening filter for Elekta and Varian linear accelerators. J Appl Clin Med Phys 2016; 17:223-235. [PMID: 27167280 PMCID: PMC5690940 DOI: 10.1120/jacmp.v17i3.6059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 01/12/2016] [Accepted: 01/11/2016] [Indexed: 11/24/2022] Open
Abstract
Flattening filter‐free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization chambers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney. Small field correction factors were generated for both FF and FFF beams. Diode measured detector response was compared with a recently published mathematical relation to predict diode response corrections in small fields. The effect of flattening filter removal on detector response was quantified using a ratio of relative detector responses in FFF and FF fields for the same field size. The removal of the flattening filter was found to have a small but measurable effect on ionization chamber response with maximum deviations of less than ±0.9% across all field sizes measured. Solid‐state detectors showed an increased dependence on the flattening filter of up to ±1.6%. Measured diode response was within ±1.1% of the published mathematical relation for all fields up to 30 mm, independent of linac type and presence or absence of a flattening filter. For 6 MV beams, detector correction factors between FFF and FF beams are interchangeable for a linac between FF and FFF modes, providing that an additional uncertainty of up to ±1.6% is accepted. PACS number(s): 87.55.km, 87.56.bd, 87.56.Da
Collapse
|
|
10
|
Boivin J, Beddar S, Guillemette M, Beaulieu L. Systematic evaluation of photodetector performance for plastic scintillation dosimetry. Med Phys 2015; 42:6211-20. [DOI: 10.1118/1.4931979] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Jonathan Boivin
- Département de Physique, de Génie physique et d'Optique, et Centre de recherche sur le cancer, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio‐Oncologie et Axe oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Québec G1R 2J6, Canada
| | - Sam Beddar
- Department of Radiation Physics, University of Texas, MD Anderson Cancer Center, Houston, Texas 77030
| | - Maxime Guillemette
- Département de Physique, de Génie physique et d'Optique, Université Laval, Québec, Québec G1V 0A6, Canada and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Québec G1V 4G5, Canada
| | - Luc Beaulieu
- Département de Physique, de Génie physique et d'Optique, et Centre de recherche sur le cancer, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio‐Oncologie et Axe oncologie du Centre de recherche du CHU de Québec, CHU de Québec, Québec, Québec G1R 2J6, Canada
| |
Collapse
|
|
11
|
O'Keeffe S, McCarthy D, Woulfe P, Grattan MWD, Hounsell AR, Sporea D, Mihai L, Vata I, Leen G, Lewis E. A review of recent advances in optical fibre sensors for in vivo dosimetry during radiotherapy. Br J Radiol 2015; 88:20140702. [PMID: 25761212 PMCID: PMC4628446 DOI: 10.1259/bjr.20140702] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/19/2015] [Accepted: 03/10/2015] [Indexed: 11/05/2022] Open
Abstract
This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry. This means that the sensor can be placed directly inside a patient, for example, for brachytherapy treatments, the optical fibres could be placed in the tumour itself or into nearby critical tissues requiring monitoring, via the same applicators or needles used for the treatment delivery thereby providing real-time dosimetric information. The article outlines the principal sensor design systems along with some of the main strengths and weaknesses associated with the development of these techniques. The successful demonstration of these sensors in a range of different clinical environments is also presented.
Collapse
Affiliation(s)
- S O'Keeffe
- Optical Fibre Sensors Research Centre, Department of Electronic and Computer Engineering, University of Limerick, Limerick, Ireland
| | - D McCarthy
- Optical Fibre Sensors Research Centre, Department of Electronic and Computer Engineering, University of Limerick, Limerick, Ireland
| | - P Woulfe
- Department of Radiotherapy Physics, Galway Clinic, Galway, Ireland
| | - M W D Grattan
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, UK
| | - A R Hounsell
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, UK
| | - D Sporea
- Laser Metrology Laboratory, National Institute for Laser, Plasma and Radiation Physics, Magurele, Romania
| | - L Mihai
- Laser Metrology Laboratory, National Institute for Laser, Plasma and Radiation Physics, Magurele, Romania
| | - I Vata
- “Horia Hulubei” National Institute of Physics and Nuclear Engineering, Magurele, Romania
| | - G Leen
- Optical Fibre Sensors Research Centre, Department of Electronic and Computer Engineering, University of Limerick, Limerick, Ireland
| | - E Lewis
- Optical Fibre Sensors Research Centre, Department of Electronic and Computer Engineering, University of Limerick, Limerick, Ireland
| |
Collapse
|
|
12
|
Warrener K, Hug B, Liu P, Ralston A, Ebert MA, McKenzie DR, Suchowerska N. Small field in-air output factors: the role of miniphantom design and dosimeter type. Med Phys 2014; 41:021723. [PMID: 24506614 DOI: 10.1118/1.4861710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The commissioning of treatment planning systems and beam modeling requires measured input parameters. The measurement of relative output in-air, Sc is particularly difficult for small fields. The purpose of this study was to investigate the influence of miniphantom design and detector selection on measured Sc values for small fields and to validate the measurements against Monte Carlo simulations. METHODS Measurements were performed using brass caps (with sidewalls) or tops (no sidewalls) of varying heights and widths. The performance of two unshielded diodes (60012 and SFD), EBT2 radiochromic film, and a fiber optic dosimeter (FOD) were compared for fields defined by MLCs (5-100 mm) and SRS cones (4-30 mm) on a Varian Novalis linear accelerator. Monte Carlo simulations were performed to theoretically predict Sc as measured by the FOD. RESULTS For all detectors, Sc agreed to within 1% for fields larger than 10 mm and to within 2.3% for smaller fields. Monte Carlo simulation matched the FOD measurements for all size of cone defined fields to within 0.5%. CONCLUSIONS Miniphantom design is the most important variable for reproducible and accurate measurements of the in-air output ratio, S(c), in small photon fields (less than 30 mm). Sidewalls are not required for fields ≤ 30 mm and tops are therefore preferred over the larger caps. Unlike output measurements in water, S(cp), the selection of detector type for Sc is not critical, provided the active dosimeter volume is small relative to the field size.
Collapse
Affiliation(s)
- Kirbie Warrener
- Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, New South Wales 2521, Australia and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Benjamin Hug
- School of Physics, University of Western Australia, Crawley, Western Australia 6009, Australia and Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia 6009, Australia
| | - Paul Liu
- School of Physics, University of Sydney, Darlington, New South Wales 2008, Australia
| | - Anna Ralston
- Chris O'Brien Lifehouse, Radiation Oncology, Sydney, New South Wales 2050, Australia
| | - Martin A Ebert
- School of Physics, University of Western Australia, Crawley, Western Australia 6009, Australia and Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia 6009, Australia
| | - David R McKenzie
- School of Physics, University of Sydney, Darlington, New South Wales 2008, Australia
| | - Natalka Suchowerska
- School of Physics, University of Sydney, Darlington, New South Wales 2008, Australia and Chris O'Brien Lifehouse, Radiation Oncology, Sydney, New South Wales 2050, Australia
| |
Collapse
|
|
13
|
Ralston A, Tyler M, Liu P, McKenzie D, Suchowerska N. Over-response of synthetic microDiamond detectors in small radiation fields. Phys Med Biol 2014; 59:5873-81. [DOI: 10.1088/0031-9155/59/19/5873] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
|
14
|
Liu PZ, Suchowerska N, McKenzie DR. Can small field diode correction factors be applied universally? Radiother Oncol 2014; 112:442-6. [DOI: 10.1016/j.radonc.2014.08.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 07/09/2014] [Accepted: 08/07/2014] [Indexed: 11/26/2022]
|
|
15
|
Prabhakar R. Real-time dosimetry in external beam radiation therapy. World J Radiol 2013; 5:352-355. [PMID: 24179630 PMCID: PMC3812446 DOI: 10.4329/wjr.v5.i10.352] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/02/2013] [Accepted: 10/12/2013] [Indexed: 02/06/2023] Open
Abstract
With growing complexity in radiotherapy treatment delivery, it has become mandatory to check each and every treatment plan before implementing clinically. This process is currently administered by an independent secondary check of all treatment parameters and as a pre-treatment quality assurance (QA) check for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy treatment plans. Although pre-treatment IMRT QA is aimed to ensure the correct dose is delivered to the patient, it does not necessarily predict the clinically relevant patient dose errors. During radiotherapy, treatment uncertainties can affect tumor control and may increase complications to surrounding normal tissues. To combat this, image guided radiotherapy is employed to help ensure the plan conditions are mimicked on the treatment machine. However, it does not provide information on actual delivered dose to the tumor volume. Knowledge of actual dose delivered during treatment aid in confirming the prescribed dose and also to replan/reassess the treatment in situations where the planned dose is not delivered as expected by the treating physician. Major accidents in radiotherapy would have been averted if real time dosimetry is incorporated as part of the routine radiotherapy procedure. Of late real-time dosimetry is becoming popular with complex treatments in radiotherapy. Real-time dosimetry can be either in the form of point doses or planar doses or projected on to a 3D image dataset to obtain volumetric dose. They either provide entrance dose or exit dose or dose inside the natural cavities of a patient. In external beam radiotherapy, there are four different established platforms whereby the delivered dose information can be obtained: (1) Collimator; (2) Patient; (3) Couch; and (4) Electronic Portal Imaging Device. Current real-time dosimetric techniques available in radiotherapy have their own advantages and disadvantages and a combination of one or more of these methods provide vital information about the actual dose delivered to radiotherapy patients.
Collapse
|
|
16
|
Cranmer-Sargison G, Liu PZY, Weston S, Suchowerska N, Thwaites DI. Small field dosimetric characterization of a new 160-leaf MLC. Phys Med Biol 2013; 58:7343-54. [DOI: 10.1088/0031-9155/58/20/7343] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
|
17
|
Liu PZY, Suchowerska N, McKenzie DR. Twisted pair of optic fibers for background removal in radiation fields. APPLIED OPTICS 2013; 52:5500-5507. [PMID: 23913071 DOI: 10.1364/ao.52.005500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/02/2013] [Indexed: 06/02/2023]
Abstract
In many situations in which an optic fiber carries a signal through a radiation field, an unwanted background signal is produced consisting of fluorescent and/or Cerenkov light. This presents a major problem in the measurement of the light signal, for example, in scintillation dosimetry of medical therapeutic beams. In this paper, we demonstrate a new method of measuring and removing the background signal through the use of a twisted pair of optic fibers. The twisted pair consists of a fiber carrying the scintillation signal that is twisted with a second optic fiber to form a double helix. The two twisted fibers will experience the same radiation environment provided the periodicity of the twist is correlated to the dose rate gradient. An expression for the required twist periodicity is presented. A scintillation dosimeter with a twisted pair optic fiber was tested in a megavoltage beam and found to accurately measure its beam characteristics. The twisted pair approach is not restricted to medical applications and can be used in many situations in which optical signals are carried through radiation fields.
Collapse
Affiliation(s)
- P Z Y Liu
- School of Physics, University of Sydney, New South Wales, Australia.
| | | | | |
Collapse
|
|
18
|
Sharma R, Jursinic PA. In vivomeasurements for high dose rate brachytherapy with optically stimulated luminescent dosimeters. Med Phys 2013; 40:071730. [DOI: 10.1118/1.4811143] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
|
19
|
Beaulieu L, Goulet M, Archambault L, Beddar S. Current status of scintillation dosimetry for megavoltage beams. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/444/1/012013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
|
20
|
Liu PZY, Suchowerska N, Lambert J, Abolfathi P, McKenzie DR. Reply to the comment on: ‘Plastic scintillation dosimetry: comparison of three solutions for the Cerenkov challenge’. Phys Med Biol 2012. [DOI: 10.1088/0031-9155/57/11/3667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|