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Bell LJ. Increasing consistency and accuracy in radiation therapy via educational interventions is not just limited to radiation oncologists. J Med Radiat Sci 2016; 63:145-7. [PMID: 27648277 PMCID: PMC5016613 DOI: 10.1002/jmrs.182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This editorial is advocating that increasing consistency and accuracy in radiation therapy via educational interventions is important for radiation therapist. Education and training with ongoing refreshers is the key to maintaining consistency throughout the radiotherapy process, which in turn will ensure all patients receive accurate treatment.![]()
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Affiliation(s)
- Linda J Bell
- Department of Radiation Oncology Northern Sydney Cancer Centre Royal North Shore Hospital St Leonards New South Wales Australia
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Bell LJ, Cox J, Eade T, Rinks M, Herschtal A, Kneebone A. Determining optimal planning target volume and image guidance policy for post-prostatectomy intensity modulated radiotherapy. Radiat Oncol 2015. [PMID: 26209446 PMCID: PMC4514953 DOI: 10.1186/s13014-015-0467-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There is limited information available on the optimal Planning Target Volume (PTV) expansions and image guidance for post-prostatectomy intensity modulated radiotherapy (PP-IMRT). As the prostate bed does not move in a uniform manner, there is a rationale for anisotropic PTV margins with matching to soft tissue. The aim of this study is to find the combination of PTV expansion and image guidance policy for PP-IMRT that provides the best balance of target coverage whilst minimising dose to the organs at risk. METHODS The Cone Beam CT (CBCT) images (n = 377) of 40 patients who received PP-IMRT with daily online alignment to bony anatomy (BA) were reviewed. Six different PTV expansions were assessed: 3 published PTV expansions (0.5 cm uniform, 1 cm uniform, and 1 + 0.5 cm posterior) and 3 further anisotropic PTV expansions (Northern Sydney Cancer Centre (NSCC), van Herk, and smaller anisotropic). Each was assessed for size, bladder and rectum coverage and geographic miss. Each CBCT was rematched using a superior soft tissue (SST) and averaged soft tissue (AST) match. Potential geographic miss was assessed using all PTV expansions except the van Herk margin. RESULTS The 0.5 cm uniform expansion yielded the smallest PTV (median volume = 222.3 cc) and the 1 cm uniform expansion yielded the largest (361.7 cc). The Van Herk expansion includes the largest amount of bladder (28.0 %) and rectum (36.0 %) and the 0.5 cm uniform expansion the smallest (17.1 % bladder; 10.2 % rectum). The van Herk PTV expansion had the least geographic miss with BA matching (4.2 %) and the 0.5 cm uniform margin (28.4 %) the greatest. BA matching resulted in the highest geographic miss rate for all PTVs, followed by SST matching and AST matching. Changing from BA to an AST match decreases potential geographic miss by half to two thirds, depending on the PTV expansion, to <10 % for all PTV expansions. When using the smaller anisotropic PTV expansion, AST matching would reduce the geographic miss rate from 21.0 % with BA matching down to 5.6 %. CONCLUSIONS Our results suggest the optimal PTV expansion and image guidance policy for PP-IMRT is daily average soft tissue matching using CBCT scans with a small anisotropic PTV expansion of 0.5 cm in all directions apart from a 1 cm expansion in the anterior-posterior direction in the upper prostate bed. Care must be taken to ensure adequate training of Radiation Therapists to perform soft tissue matching with CBCT scans.
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Affiliation(s)
- Linda J Bell
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia. .,Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia.
| | - Jennifer Cox
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia.,Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia
| | - Thomas Eade
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia.,Northern Clinical School, University of Sydney, St Leonards, NSW, Australia
| | - Marianne Rinks
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia.,Present address: Radiation Oncology, Shoalhaven Cancer Care Centre, Illawarra Shoalhaven Local Health District, Nowra, NSW, Australia
| | - Alan Herschtal
- Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Andrew Kneebone
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards, NSW, Australia.,Northern Clinical School, University of Sydney, St Leonards, NSW, Australia
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Bell LJ, Cox J, Eade T, Rinks M, Kneebone A. Definition and visualisation of regions of interest in post-prostatectomy image-guided intensity modulated radiotherapy. J Med Radiat Sci 2014; 61:166-75. [PMID: 26229653 PMCID: PMC4175845 DOI: 10.1002/jmrs.58] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/15/2014] [Accepted: 05/28/2014] [Indexed: 11/30/2022] Open
Abstract
Introduction Standard post-prostatectomy radiotherapy (PPRT) image verification uses bony anatomy alignment. However, the prostate bed (PB) moves independently of bony anatomy. Cone beam computed tomography (CBCT) can be used to soft tissue match, so radiation therapists (RTs) must understand pelvic anatomy and PPRT clinical target volumes (CTV). The aims of this study are to define regions of interest (ROI) to be used in soft tissue matching image guidance and determine their visibility on planning CT (PCT) and CBCT. Methods Published CTV guidelines were used to select ROIs. The PCT scans (n = 23) and CBCT scans (n = 105) of 23 post-prostatectomy patients were reviewed. Details on ROI identification were recorded. Results Eighteen patients had surgical clips. All ROIs were identified on PCTs at least 90% of the time apart from mesorectal fascia (MF) (87%) due to superior image quality. When surgical clips are present, the seminal vesicle bed (SVB) was only seen in 2.3% of CBCTs and MF was unidentifiable. Most other structures were well identified on CBCT. The anterior rectal wall (ARW) was identified in 81.4% of images and penile bulb (PB) in 68.6%. In the absence of surgical clips, the MF and SVB were always identified; the ARW was identified in 89.5% of CBCTs and PB in 73.7%. Conclusions Surgical clips should be used as ROIs when present to define SVB and MF. In the absence of clips, SVB, MF and ARW can be used. RTs must have a strong knowledge of soft tissue anatomy and PPRT CTV to ensure coverage and enable soft tissue matching.
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Affiliation(s)
- Linda J Bell
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital St Leonards, New South Wales, Australia ; Faculty of Health Sciences, University of Sydney Lidcombe, New South Wales, Australia
| | - Jennifer Cox
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital St Leonards, New South Wales, Australia ; Faculty of Health Sciences, University of Sydney Lidcombe, New South Wales, Australia
| | - Thomas Eade
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital St Leonards, New South Wales, Australia
| | - Marianne Rinks
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital St Leonards, New South Wales, Australia
| | - Andrew Kneebone
- Radiation Oncology Department, Northern Sydney Cancer Centre, Royal North Shore Hospital St Leonards, New South Wales, Australia
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Deegan T, Owen R, Holt T, Fielding A, Biggs J, Parfitt M, Coates A, Roberts L. Assessment of cone beam CT registration for prostate radiation therapy: fiducial marker and soft tissue methods. J Med Imaging Radiat Oncol 2014; 59:91-8. [PMID: 24953244 DOI: 10.1111/1754-9485.12197] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/24/2014] [Indexed: 12/11/2022]
Abstract
INTRODUCTION This investigation aimed to assess the consistency and accuracy of radiation therapists (RTs) performing cone beam computed tomography (CBCT) alignment to fiducial markers (FMs) (CBCTFM ) and the soft tissue prostate (CBCTST ). METHODS Six patients receiving prostate radiation therapy underwent daily CBCTs. Manual alignment of CBCTFM and CBCTST was performed by three RTs. Inter-observer agreement was assessed using a modified Bland-Altman analysis for each alignment method. Clinically acceptable 95% limits of agreement with the mean (LoAmean ) were defined as ±2.0 mm for CBCTFM and ±3.0 mm for CBCTST . Differences between CBCTST alignment and the observer-averaged CBCTFM (AvCBCTFM ) alignment were analysed. Clinically acceptable 95% LoA were defined as ±3.0 mm for the comparison of CBCTST and AvCBCTFM . RESULTS CBCTFM and CBCTST alignments were performed for 185 images. The CBCTFM 95% LoAmean were within ±2.0 mm in all planes. CBCTST 95% LoAmean were within ±3.0 mm in all planes. Comparison of CBCTST with AvCBCTFM resulted in 95% LoA of -4.9 to 2.6, -1.6 to 2.5 and -4.7 to 1.9 mm in the superior-inferior, left-right and anterior-posterior planes, respectively. CONCLUSIONS Significant differences were found between soft tissue alignment and the predicted FM position. FMs are useful in reducing inter-observer variability compared with soft tissue alignment. Consideration needs to be given to margin design when using soft tissue matching due to increased inter-observer variability. This study highlights some of the complexities of soft tissue guidance for prostate radiation therapy.
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Affiliation(s)
- Timothy Deegan
- Radiation Therapy Services, Radiation Oncology Mater Centre, Brisbane, Queensland, Australia; Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
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