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SBRT for Localized Prostate Cancer: CyberKnife vs. VMAT-FFF, a Dosimetric Study. Life (Basel) 2022; 12:life12050711. [PMID: 35629378 PMCID: PMC9144859 DOI: 10.3390/life12050711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 12/14/2022] Open
Abstract
In recent years, stereotactic body radiation therapy (SBRT) has gained popularity among clinical methods for the treatment of medium and low risk prostate cancer (PCa), mainly as an alternative to surgery. The hypo-fractionated regimen allows the administration of high doses of radiation in a small number of fractions; such a fractionation is possible by exploiting the different intrinsic prostate radiosensitivity compared with the surrounding healthy tissues. In addition, SBRT treatment guaranteed a better quality of life compared with surgery, avoiding risks, aftermaths, and possible complications. At present, most stereotactic prostate treatments are performed with the CyberKnife (CK) system, which is an accelerator exclusively dedicated for stereotaxis and it is not widely spread in every radiotherapy centre like a classic linear accelerator (LINAC). To be fair, a stereotactic treatment is achievable also by using a LINAC through Volumetric Modulated Arc Therapy (VMAT), but some precautions must be taken. The aim of this work is to carry out a dosimetric comparison between these two methodologies. In order to pursue such a goal, two groups of patients were selected at Instituto Nazionale Tumori—IRCCS Fondazione G. Pascale: the first group consisting of ten patients previously treated with a SBRT performed with CK; the second one was composed of ten patients who received a hypo-fractionated VMAT treatment and replanned in VMAT-SBRT flattening filter free mode (FFF). The two SBRT techniques were rescaled at the same target coverage and compared by normal tissue sparing, dose distribution parameters and delivery time. All organs at risk (OAR) constraints were achieved by both platforms. CK exhibits higher performances in terms of dose delivery; nevertheless, the general satisfying dosimetric results and the significantly shorter delivery time make VMAT-FFF an attractive and reasonable alternative SBRT technique for the treatment of localized prostate cancer.
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Grimwood A, Thomas K, Kember S, Aldis G, Lawes R, Brigden B, Francis J, Henegan E, Kerner M, Delacroix L, Gordon A, Tree A, Harris EJ, McNair HA. Factors affecting accuracy and precision in ultrasound guided radiotherapy. Phys Imaging Radiat Oncol 2021; 18:68-77. [PMID: 34258411 PMCID: PMC8254201 DOI: 10.1016/j.phro.2021.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/04/2021] [Accepted: 05/11/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Transperineal ultrasound (TPUS) is used clinically for directly assessing prostate motion. Factors affecting accuracy and precision in TPUS motion estimation must be assessed to realise its full potential. METHODS AND MATERIALS Patients were imaged using volumetric TPUS during the Clarity-Pro trial (NCT02388308). Prostate motion was measured online at patient set-up and offline by experienced observers. Cone beam CT with markers was used as a comparator and observer performance was also quantified. The influence of different clinical factors was examined to establish specific recommendations towards efficacious ultrasound guided radiotherapy. RESULTS From 330 fractions in 22 patients, offline observer random errors were 1.5 mm, 1.3 mm, 1.9 mm (left-right, superior-inferior, anteroposterior respectively). Errors increased in fractions exhibiting poor image quality to 3.3 mm, 3.3 mm and 6.8 mm. Poor image quality was associated with inconsistent probe placement, large anatomical changes and unfavourable imaging conditions within the patient. Online matching exhibited increased observer errors of: 3.2 mm, 2.9 mm and 4.7 mm. Four patients exhibited large systematic residual errors, of which three had poor quality images. Patient habitus showed no correlation with observer error, residual error, or image quality. CONCLUSIONS TPUS offers the unique potential to directly assess inter- and intra-fraction motion on conventional linacs. Inconsistent image quality, inexperienced operators and the pressures of the clinical environment may degrade precision and accuracy. Experienced operators are essential and cross-centre standards for training and QA should be established that build upon current guidance. Greater use of automation technologies may further minimise uncertainties.
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Affiliation(s)
- Alexander Grimwood
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
- Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Karen Thomas
- Department of Statistics and Computing, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Sally Kember
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Georgina Aldis
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Rebekah Lawes
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Beverley Brigden
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Jane Francis
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Emer Henegan
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Melanie Kerner
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Louise Delacroix
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Alexandra Gordon
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Alison Tree
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Emma J. Harris
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
- Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
| | - Helen A. McNair
- Department of Radiotherapy, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom
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