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Sakai Y, Monzen H, Takei Y, Kosaka H, Nakamura K, Yanagi Y, Wakabayashi K, Hosono M, Nishimura Y. Evaluation of In-room Volumetric Imaging Doses for Image-guided Radiotherapy: A Multi-institutional Study. J Med Phys 2023; 48:189-194. [PMID: 37576099 PMCID: PMC10419753 DOI: 10.4103/jmp.jmp_109_22] [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: 12/07/2022] [Revised: 05/10/2023] [Accepted: 05/22/2023] [Indexed: 08/15/2023] Open
Abstract
Aims We investigated imaging dose and noise under clinical scan conditions at multiple institutions using a simple and unified method, and demonstrated the need for diagnostic reference levels in image-guided radiotherapy (IGRT). Materials and Methods Nine cone-beam and helical computed tomography (CT) scanners (Varian, Elekta, Accuray Inc., and BrainLAB) from seven institutions were investigated in this study. The weighted cone-beam dose index (CBDIw) was calculated for head and pelvic protocols using a 100 mm pencil chamber under the conditions used in actual clinical practice at each institution. Cone-beam CT image noise was evaluated using polymethylmethacrylate head and body phantoms with diameters of 16 and 32 cm, respectively. Results For head and pelvic protocols, CBDIw values ranged from 0.94-6.59 and 1.47-20.9 mGy, respectively. Similarly, standard deviation (SD) values ranged from 9.3-34.0 and 26.9-97.4 HU, respectively. The SD values tended to increase with decreasing imaging dose (r = -0.33 and -0.61 for the head and pelvic protocols, respectively). Conclusions Among the nine machines, the imaging dose for high imaging dose institutions was approximately 20 mGy to the pelvic phantom, and there was a 14-fold difference in dose compared with the other institutions. These results suggest the need to establish DRLs for IGRT to guide clinical decision-making.
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Affiliation(s)
- Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
- Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Yoshiki Takei
- Department of Radiology, Kindai University Nara Hospital, Ikoma, Nara, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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UroLift implants as surrogate fiducial markers for cone-beam CT-based prostate image-guided radiotherapy. JOURNAL OF RADIOTHERAPY IN PRACTICE 2023. [DOI: 10.1017/s1460396923000092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Abstract
Introduction:
UroLift implants are a novel treatment for the obstructive lower urinary tract symptoms arising from benign prostatic hyperplasia. This case study aimed to assess their effectiveness as fiducial marker (FM) surrogates in prostate image-guided radiotherapy (IGRT).
Method:
Cone-beam CT images from a patient receiving prostate radiation therapy underwent manual alignment using UroLift implants and also prostate soft-tissue matching by five experienced therapeutic radiographers. The match values of both methods were compared using Bland–Altman analysis. All five observers were also asked to score the ease of matching using both approaches.
Results:
The 95% mean level of agreement for the UroLift matches were within a 2-mm threshold in all dimensions. Comparison of UroLift and prostate matches had 95% limit of agreement values of −0·98 to 1·78, −0·58 to 0·49 and −1·83 to 1·04 mm in the vertical, longitudinal and lateral planes, respectively. All of the UroLift matches were rated as ‘very easy’ or ‘possible with little difficulty’ by the five observers.
Conclusion:
A small difference between the CBCT UroLift and CBCT prostate match was found. It has been shown that IGRT to the prostate with the aid of the UroLift system implants and CBCT is feasible and can eliminate the need for FM implants. Wider evaluation in a large cohort is recommended.
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Khan M, Sandhu N, Naeem M, Ealden R, Pearson M, Ali A, Honey I, Webster A, Eaton D, Ntentas G. Implementation of a comprehensive set of optimised CBCT protocols and validation through imaging quality and dose audit. Br J Radiol 2022; 95:20220070. [PMID: 36000497 PMCID: PMC9793481 DOI: 10.1259/bjr.20220070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Cone-beam computed tomography (CBCT) for radiotherapy treatment verification has increased in frequency; therefore, it is crucial to optimise image quality and radiation dose to patients. The aim of this study was to implement optimised CBCT protocols for the Varian TrueBeams for most tumour sites in adult patients. METHODS A combination of patient size-specific CBCT protocols from the literature and developed in-house was used. Scans taken before and after optimisation were compared by senior radiographers and physicists to evaluate how changes affected image quality and clinical usability for online image registration. The change in dose for each new CBCT protocol was compared to the Varian default. A clinical audit was performed following implementation to evaluate the changes in imaging dose for all patients receiving a CBCT during that period. RESULTS Ten CBCT protocols were introduced including head and neck and patient-size-specific thorax and pelvis/abdomen protocols. Scans from 102 patients with images before and after optimisation were assessed, none of the scans showed image quality changes compromising clinical usability and for some image quality was improved. Between November 2020 and June 2021, 1185 patients had CBCTs using the new protocols. The imaging dose was reduced for 52% of patients, remained the same for 37% and increased for 12%. CONCLUSIONS This study showed that substantial dose reductions and image quality improvements can be achieved with simple changes in the default settings of the Varian TrueBeam CBCT without affecting the radiographers' confidence in online image registration. ADVANCES IN KNOWLEDGE This study represents a comprehensive assessment and optimisation of CBCT protocols for most sites, validated on a large cohort of patients.
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Affiliation(s)
- Marina Khan
- Department of Radiotherapy, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Navneet Sandhu
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Marium Naeem
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Rebecca Ealden
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Michael Pearson
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Abdirzak Ali
- Department of Radiotherapy, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Ian Honey
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Amanda Webster
- Department of Radiotherapy, University College Hospital, London, UK
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PCXMC cone beam computed tomography dosimetry investigations. Phys Eng Sci Med 2022; 45:205-218. [PMID: 35072895 DOI: 10.1007/s13246-022-01103-9] [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: 08/02/2021] [Accepted: 01/07/2022] [Indexed: 10/19/2022]
Abstract
With cone beam computed tomography (CBCT) in image guided radiation therapy being amongst the most widely used imaging modalities, there has been an increasing interest in quantifying the concomitant dose and risk. Whilst there have been several studies on this topic, there remains a lack of standardisation and knowledge on dose variations and the impact of patient size. Recently, PCXMC (a Monte Carlo simulator) has been used to assess both the concomitant dose and dosimetric impact of patient size variations for CBCT. The scopes of these studies, however, have included only a limited range of imaging manufacturers, protocols, and patient sizes. An approach using PCXMC and MATLAB was developed to enable a generalised method for rapidly quantifying and formulating the concomitant dose as a function of patient size across numerous CBCT vendors and protocols. The method was investigated using the Varian on board imaging 1.6 default pelvis and pelvis spotlight protocols, for 94 adult and paediatric phantoms over 6 age groups with extensive height and mass variations. It was found that dose varies significantly with patient size, as much as doubling and halving the average for patients of lower and higher mass, respectively. These variations, however, can be formulated and accounted for using the method developed, across a wide range of patient sizes for all CBCT vendors and protocols. This will enable the development of a comprehensive catalogue to account for concomitant doses in almost any clinically relevant scenario.
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Le Deroff C, Berger L, Bellec J, Boissonnat G, Chesneau H, Chiavassa S, Desrousseaux J, Gempp S, Henry O, Jarril J, Lazaro D, Lefeuvre R, Passal V, Solinhac F, Lafond C, Delpon G. Monte Carlo-based software for 3D personalized dose calculations in image-guided radiotherapy. Phys Imaging Radiat Oncol 2022; 21:108-114. [PMID: 35243041 PMCID: PMC8885460 DOI: 10.1016/j.phro.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/28/2022] [Accepted: 02/11/2022] [Indexed: 11/23/2022] Open
Abstract
Monte Carlo calculations offer 3D personalized IGRT imaging dose distributions. Histogram dose volume were obtained for three anatomical sites and 5 imaging device. The image frequency is responsible for the cumulated dose to organs. Adapting the protocols to morphologies reduce the imaging dose.
Background and purpose Image-guided radiotherapy (IGRT) involves frequent in-room imaging sessions contributing to additional patient irradiation. The present work provided patient-specific dosimetric data related to different imaging protocols and anatomical sites. Material and methods We developed a Monte Carlo based software able to calculate 3D personalized dose distributions for five imaging devices delivering kV-CBCT (Elekta and Varian linacs), MV-CT (Tomotherapy machines) and 2D-kV stereoscopic images from BrainLab and Accuray. Our study reported the dose distributions calculated for pelvis, head and neck and breast cases based on dose volume histograms for several organs at risk. Results 2D-kV imaging provided the minimum dose with less than 1 mGy per image pair. For a single kV-CBCT and MV-CT, median dose to organs were respectively around 30 mGy and 15 mGy for the pelvis, around 7 mGy and 10 mGy for the head and neck and around 5 mGy and 15 mGy for the breast. While MV-CT dose varied sparsely with tissues, dose from kV imaging was around 1.7 times higher in bones than in soft tissue. Daily kV-CBCT along 40 sessions of prostate radiotherapy delivered up to 3.5 Gy to the femoral heads. The dose level for head and neck and breast appeared to be lower than 0.4 Gy for every organ in case of a daily imaging session. Conclusions This study showed the dosimetric impact of IGRT procedures. Acquisition parameters should therefore be chosen wisely depending on the clinical purposes and tailored to morphology. Indeed, imaging dose could be reduced up to a factor 10 with optimized protocols.
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Affiliation(s)
- Coralie Le Deroff
- Centre Eugène Marquis (Unicancer), Rennes, France
- Corresponding author.
| | - Lucie Berger
- Centre Jean Perrin (Unicancer), Clermont Ferrand, France
| | | | | | | | - Sophie Chiavassa
- Institut de Cancérologie de l’Ouest (Unicancer), Saint-Herblain, France
| | | | - Stéphanie Gempp
- Assistance Publique – Hôpitaux de Marseille, Marseille, France
| | | | - Jimmy Jarril
- Centre Jean Perrin (Unicancer), Clermont Ferrand, France
| | - Delphine Lazaro
- Université Paris-Saclay, CEA, List, F-91120 Palaiseau, France
| | | | - Vincent Passal
- Institut de Cancérologie de l’Ouest (Unicancer), Saint-Herblain, France
| | - Fanny Solinhac
- Assistance Publique – Hôpitaux de Marseille, Marseille, France
| | - Caroline Lafond
- Centre Eugène Marquis (Unicancer), Rennes, France
- Université de Rennes, Inserm, LTSI – UMR 1099, Rennes, France
| | - Gregory Delpon
- Institut de Cancérologie de l’Ouest (Unicancer), Saint-Herblain, France
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Optimisation of Varian TrueBeam head, thorax and pelvis CBCT based on patient size. JOURNAL OF RADIOTHERAPY IN PRACTICE 2021. [DOI: 10.1017/s1460396920000618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractPurpose:The aim of this study was to optimise patient dose and image quality of Varian TrueBeam cone beam computed tomography (CBCT) pelvis, thorax and head and neck (H&N) images based on patient size.Methods:An elliptical phantom of small, medium and large size was designed representative of a local population of pelvis, thorax and H&N patients. The phantom was used to establish the relationship between image noise, CT and CBCT exposure settings. Using this insight, clinical images were optimised in phases and the image quality graded qualitatively by radiographers. At each phase, the time required to match the images was recorded from the record and verify system.Results:Average patient diameter was a suitable metric to categorise patient size. Phantom measurements showed the power relationship between noise and CBCT exposure settings of value −0·15, −0·35 and −0·43 for thorax, pelvis and H&N, respectively. These quantitative phantom measurements provided confidence that phased variation of ~±20% in mAs should result in clinically usable images. Qualitative assessment of almost 2000 images reduced the exposure settings in H&N images by −50%, thorax images by up to −66% and pelvis images by up to −80%. These optimised CBCT settings did not affect the time required to match images.Findings:Varian TrueBeam CBCT mAs settings have been optimised for dose and image quality based on patient size for three treatment sites: pelvis, thorax and H&N. Quantitative phantom measurements provided insight into the magnitude of change to implement clinically. The final optimised exposure settings were determined from radiographer qualitative image assessment.
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Delpon G, Lazaro D, de Crevoisier R. [Management of image guidance doses delivered during radiotherapy]. Cancer Radiother 2021; 25:790-794. [PMID: 33390319 DOI: 10.1016/j.canrad.2020.05.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/29/2020] [Accepted: 05/18/2020] [Indexed: 11/30/2022]
Abstract
Image-guided radiotherapy (IGRT) has become a standard irradiation technique to improve the clinical outcome of patients in terms of toxicity and local control due to better targeting of radiation during the irradiation fraction. Positioning imaging systems, whether embedded or not, such as kV for 2×2D acquisitions and especially kVCBCT for 3D acquisitions are however irradiating in a large volume including the target volume but also healthy tissue, with a theoretical risk of increased toxicity and second cancer. It therefore appears very important both to optimize the absorbed dose due to IGRT practice but also to report it, especially in case of kVCBCT. The AAPM report published in 2018 (« Image guidance doses delivered during radiotherapy: Quantification, management, and reduction ») proposes a management of image guidance doses delivered during radiotherapy. This report is the basis of this focus article that aims at giving orders of magnitude and proposing a management of image guidance doses delivered during radiotherapy in clinical practice. The dose delivered per kVCBCT is about 0.5 to 2 cGy at isocenter according to treatment site. As long as the calculation algorithms are not available in the treatment planning systems, it seems appropriate to use at least the published dose orders of magnitude. This estimate should ultimately allow the clinician to decide on the therapeutic strategy in the event of accumulation of positioning imaging sessions.
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Affiliation(s)
- G Delpon
- Service de physique médicale, institut de cancérologie de l'Ouest, boulevard Jacques-Monod, 44805 Nantes Saint-Herblain, France.
| | - D Lazaro
- Laboratoire modélisation et simulation des systèmes, CEA-LIST, Saclay, France
| | - R de Crevoisier
- Service de radiothérapie, Centre Eugène Marquis, Rennes, France
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Piliero MA, Casiraghi M, Bosetti DG, Cima S, Deantonio L, Leva S, Martucci F, Tettamanti M, Pupillo F, Bellesi L, Richetti A, Presilla S. Patient-based low dose cone beam CT acquisition settings for prostate image-guided radiotherapy treatments on a Varian TrueBeam linear accelerator. Br J Radiol 2020; 93:20200412. [PMID: 32822249 PMCID: PMC8519649 DOI: 10.1259/bjr.20200412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE To evaluate the performance of low dose cone beam CT (CBCT) acquisition protocols for image-guided radiotherapy of prostate cancer. METHODS CBCT images of patients undergoing prostate cancer radiotherapy were acquired with the settings currently used in our department and two low dose settings at 50% and 63% lower exposure. Four experienced radiation oncologists and two radiation therapy technologists graded the images on five image quality characteristics. The scores were analysed through Visual Grading Regression, using the acquisition settings and the patient size as covariates. RESULTS The low dose acquisition settings have no impact on the image quality for patients with body profile length at hip level below 100 cm. CONCLUSIONS A reduction of about 60% of the dose is feasible for patients with size below 100 cm. The visibility of low contrast features can be compromised if using the low dose acquisition settings for patients with hip size above 100 cm. ADVANCES IN KNOWLEDGE Low dose CBCT acquisition protocols for the pelvis, based on subjective evaluation of patient images.
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Affiliation(s)
- Maria Antonietta Piliero
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland
| | - Margherita Casiraghi
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland
| | - Davide Giovanni Bosetti
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Simona Cima
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Letizia Deantonio
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Stefano Leva
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Francesco Martucci
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Marino Tettamanti
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Francesco Pupillo
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland
| | - Luca Bellesi
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland
| | - Antonella Richetti
- Radiation Oncology Clinic, Oncology Institute of Southern Switzerland, 6500 Bellinzona, Switzerland
| | - Stefano Presilla
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland
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Winters E, Poole C. Challenges and impact of patient obesity in radiation therapy practice. Radiography (Lond) 2020; 26:e158-e163. [PMID: 32052747 DOI: 10.1016/j.radi.2020.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 01/02/2020] [Accepted: 01/13/2020] [Indexed: 12/31/2022]
Abstract
INTRODUCTION The prevalence of obesity is rapidly increasing globally and has tripled between 1975 and 2016. Obesity is reported within the literature as having a significant impact on medical practice, professionals, imaging departments and healthcare systems. It is not known how this epidemic will impact radiation therapists' working environment and practice. The aim of this study is to explore the perceived challenges and impacts of patient obesity on radiation therapy practice from the perception of radiation therapists. METHODS All radiation therapists working in the Republic of Ireland were invited to participate. Two focus groups were conducted with 6 and 7 participants respectively. A seven staged method of analysis, using a computerised long table approach was developed and used to analyse the data and create themes related to radiation therapists' perception of managing obese patients. RESULTS Perceived challenges from the radiation therapists were difficulties; (1) Setting up the patient (2) Imaging (3) communication and emotional impact. CONCLUSION An array of concerns were raised during this research about the increase and impact of obese patients on radiation therapists working environment. This study suggests that obese patients can present additional challenges to radiation therapists' current work practices. It is imperative that we recognise the additional challenges this patient cohort add to daily workflow. Further research is needed to identify the common key issues and how to manage this specific patient group. IMPLICATIONS FOR PRACTICE At the moment there are no specific management strategies/policies in place for managing obese patients; this study suggests that it is something we need to consider implementing as standard in radiation therapy departments.
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Affiliation(s)
- E Winters
- Trinity College Dublin, Applied Radiation Therapy Trinity, School of Medicine, Trinity College Dublin, Ireland.
| | - C Poole
- Trinity College Dublin, Applied Radiation Therapy Trinity, School of Medicine, Trinity College Dublin, Ireland.
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Yuan Z, Rong Y, Benedict SH, Daly ME, Qiu J, Yamamoto T. "Dose of the day" based on cone beam computed tomography and deformable image registration for lung cancer radiotherapy. J Appl Clin Med Phys 2019; 21:88-94. [PMID: 31816170 PMCID: PMC6964750 DOI: 10.1002/acm2.12793] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/04/2019] [Accepted: 11/17/2019] [Indexed: 12/25/2022] Open
Abstract
Purpose Adaptive radiotherapy (ART) has potential to reduce toxicity and facilitate safe dose escalation. Dose calculations with the planning CT deformed to cone beam CT (CBCT) have shown promise for estimating the “dose of the day”. The purpose of this study is to investigate the “dose of the day” calculation accuracy based on CBCT and deformable image registration (DIR) for lung cancer radiotherapy. Methods A total of 12 lung cancer patients were identified, for which daily CBCT imaging was performed for treatment positioning. A re‐planning CT (rCT) was acquired after 20 Gy for all patients. A virtual CT (vCT) was created by deforming initial planning CT (pCT) to the simulated CBCT that was generated from deforming CBCT to rCT acquired on the same day. Treatment beams from the initial plan were copied to the vCT and rCT for dose calculation. Dosimetric agreement between vCT‐based and rCT‐based accumulated doses was evaluated using the Bland‐Altman analysis. Results Mean differences in dose‐volume metrics between vCT and rCT were smaller than 1.5%, and most discrepancies fell within the range of ± 5% for the target volume, lung, esophagus, and heart. For spinal cord Dmax, a large mean difference of −5.55% was observed, which was largely attributed to very limited CBCT image quality (e.g., truncation artifacts). Conclusion This study demonstrated a reasonable agreement in dose‐volume metrics between dose accumulation based on vCT and rCT, with the exception for cases with poor CBCT image quality. These findings suggest potential utility of vCT for providing a reasonable estimate of the “dose of the day”, and thus facilitating the process of ART for lung cancer.
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Affiliation(s)
- Zilong Yuan
- Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA, USA.,Department of Radiology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Rong
- Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA, USA
| | - Stanley H Benedict
- Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA, USA
| | - Megan E Daly
- Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA, USA
| | - Jianfeng Qiu
- Medical Engineering and Technology Research Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Tokihiro Yamamoto
- Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA, USA
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Chan S, Giles E, Newmarch L, Short M. Effect of patient size on image quality in radiotherapy kV planar verification imaging: a phantom study. J Med Radiat Sci 2019; 67:34-42. [PMID: 31621206 PMCID: PMC7063253 DOI: 10.1002/jmrs.355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/08/2019] [Accepted: 08/10/2019] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION This study aimed to determine a maximal pelvic separation and waist circumference in pelvic patients to guide radiation therapists in acquiring kilovoltage (kV) planar images of acceptable quality for treatment verification. METHODS A pelvic anthropomorphic phantom modified with different bolus thicknesses was imaged at various default kV exposure settings. Radiation therapists rated image quality and acceptance/rejection of these images for treatment verification. RESULTS Sixteen radiation therapists participated in the study. Image quality was inversely proportional to phantom size. AP and lateral kV images were acceptable for treatment verification up to a waist circumference of 143 cm. CONCLUSIONS Exposure settings for kV image verification of large patients should be individualised to avoid unnecessary patient radiation dose through repeated imaging.
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Affiliation(s)
- Sara Chan
- Centre for Translational Cancer Research, UniSA Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia.,Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Eileen Giles
- Centre for Translational Cancer Research, UniSA Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Lyndal Newmarch
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Michala Short
- Centre for Translational Cancer Research, UniSA Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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Moore CS, Wood TJ, Saunderson JR, Beavis AW. The usefulness of large sample size patient dose audits for optimisation of CT automatic exposure control (AEC) settings. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2019; 39:938-949. [PMID: 31382249 DOI: 10.1088/1361-6498/ab3894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The aim of this study was to demonstrate the usefulness of large sample size patient dose audits for optimisation of CT automatic exposure control (AEC) settings, even when the investigation is limited to only three scanners at a single institution. Pre-optimisation patient dose audits of common CT examinations (n > 200 for each protocol) on three CT scanners (two Philips Brilliance and one Toshiba Aquilion) using radiology information system (RIS) data were conducted showing sub-optimal CT AEC performance on the Toshiba scanner. Based on these results, an optimisation exercise was carried out on the non-optimally performing scanner by phantom measurement and investigation of system configuration. Post-optimisation patient dose audits were subsequently carried out to assess the success of the optimisation exercise demonstrating standardisation of doses; median dose-length-product values were reduced by up to 43% on the sub-optimal scanner without any adverse effect on clinical image quality. This study has demonstrated that large sample patient dose audits using RIS data can be instrumental in identifying and rectifying sub-optimal CT AEC performance, even when the investigation is limited to only three scanners at a single institution.
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Affiliation(s)
- Craig S Moore
- Medical Physics Service, Queen's Centre, Castle Hill Hospital, Hull University Teaching Hospitals NHS Trust, Castle Road, Hull, HU16 5JQ, United Kingdom
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Men K, Dai J. A comprehensive evaluation of angular range and separation on image quality, image registration, and imaging dose for cone beam computed tomography in radiotherapy. Med Dosim 2019; 44:67-73. [DOI: 10.1016/j.meddos.2018.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/16/2018] [Accepted: 02/12/2018] [Indexed: 12/31/2022]
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Troy KL, Edwards WB. Practical considerations for obtaining high quality quantitative computed tomography data of the skeletal system. Bone 2018; 110:58-65. [PMID: 29339151 DOI: 10.1016/j.bone.2018.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/09/2018] [Accepted: 01/09/2018] [Indexed: 11/20/2022]
Abstract
Quantitative CT (QCT) analysis involves the calculation of specific parameters such as bone volume and density from CT image data, and can be a powerful tool for understanding bone quality and quantity. However, without careful attention to detail during all steps of the acquisition and analysis process, data can be of poor- to unusable-quality. Good quality QCT for research requires meticulous attention to detail and standardization of all aspects of data collection and analysis to a degree that is uncommon in a clinical setting. Here, we review the literature to summarize practical and technical considerations for obtaining high quality QCT data, and provide examples of how each recommendation affects calculated variables. We also provide an overview of the QCT analysis technique to illustrate additional opportunities to improve data reproducibility and reliability. Key recommendations include: standardizing the scanner and data acquisition settings, minimizing image artifacts, selecting an appropriate reconstruction algorithm, and maximizing repeatability and objectivity during QCT analysis. The goal of the recommendations is to reduce potential sources of error throughout the analysis, from scan acquisition to the interpretation of results.
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Affiliation(s)
- Karen L Troy
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, United States.
| | - W Brent Edwards
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada
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Yang CC, Yu PC, Ruan JM, Chen YC. Optimizing the target detectability of cone beam CT performed in image-guided radiation therapy for patients of different body sizes. J Appl Clin Med Phys 2018. [PMID: 29516610 PMCID: PMC5978665 DOI: 10.1002/acm2.12306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purpose The target detectability of cone beam computed tomography (CBCT) performed in image‐guided radiation therapy (IGRT) was investigated to achieve sufficient image quality for patient positioning over a course of treatment session while maintaining radiation exposure from CBCT imaging as low as reasonably achievable (ALARA). Methods Body CBCT scans operated in half‐fan mode were acquired with three different protocols: CBCTlowD, CBCTmidD, and CBCThighD, which resulted in weighted CT dose index (CTDIw) of 0.36, 1.43, and 2.78 cGy, respectively. An electron density phantom that is 18 cm in diameter was covered by four layers of 2.5‐cm‐thick bolus to simulate patients of different body sizes. Multivariate analysis was used to examine the impact of body size, radiation exposure, and tissue type on the target detectability of CBCT imaging, quantified as contrast‐to‐noise ratio (CNR). Results CBCTmidD allows sufficient target detection of adipose, breast, muscle, liver in a background of water for normal‐weight adults with cross‐sectional diameter less than 28 cm, while CBCThighD is suitable for adult patients with larger body sizes or body mass index over 25 kg/m2. Once the cross‐sectional diameter of adult patients is larger than 35 cm, the CTDIw of CBCT scans should be higher than 2.78 cGy to achieve required CNR. As for pediatric and adolescent patients with cross‐sectional diameter less than 25 cm, CBCTlowD is able to produce images with sufficient target detection. Conclusion The target detectability of soft tissues in default CBCT scans may not be sufficient for overweight or obese adults. Contrary, pediatric and adolescent patients would receive unnecessarily high radiation exposure from default CBCT scans. Therefore, the selection of acquisition parameters for CBCT scans optimized according to patient body size was proposed to ensure sufficient image quality for daily patient positioning in radiation therapy while achieving the ALARA principle.
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Affiliation(s)
- Ching-Ching Yang
- Department of Medical Imaging and Radiological Sciences, Tzu-Chi University of Science and Technology, Hualien, Taiwan
| | - Pei-Chieh Yu
- Department of Radiation Oncology, Cathay General Hospital, Taipei, Taiwan.,School of Medicine, China Medical University, Taichung, Taiwan
| | - Jau-Ming Ruan
- Department of Radiation Oncology, Cathay General Hospital, Taipei, Taiwan
| | - Yu-Cheng Chen
- Department of Radiation Oncology, Cathay General Hospital, Taipei, Taiwan
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