Verification of prostate treatment setup using computed radiography for portal imaging

Whittington, Richard; Bloch, Peter; Hutchinson, Della; Bjärngard, Bengt E.

doi:10.1120/jacmp.v3i2.2582

Cited by 8 publications

(7 citation statements)

References 21 publications

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“…A few authors have tried portal imaging with computed radiography (CR), a non-film-based system, used to obtain high quality portal images. In this system, the film is replaced with a photostimulable phosphor plate [ 8 ]. In addition to the advantages of digital imaging, this technique produces excellent images with radiation exposures of 1 and 2 monitor units (MU) only.…”

Section: Dose Optimisation During Portal Imaging In Radiation Therapymentioning

confidence: 99%

Dose optimisation during imaging in radiotherapy

Ravindran

2007

Biomed. Imaging Interv. J.

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The desire to increase the precision in radiotherapy delivery has led to the development of advanced imaging systems such as amorphous silicon (a-Si)-based electronic portal imaging, and kV and MV cone beam CT. These are used prior to the delivery of radiation to visualise the organ to be treated and to ensure that the patient setup and treatment delivery are accurate. However, little attention has been given to the dose received by adjacent normal tissues during these imaging procedures. Though these doses are very small compared to the dose delivered during radiotherapy, the involvement of normal tissues and the concern that these could increase the probability of stochastic effect, mainly the induction of secondary malignancy, cannot be ignored. This article reviews some work on the doses received during imaging in radiotherapy and the methods to optimise the same.

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Section: Dose Optimisation During Portal Imaging In Radiation Therapymentioning

confidence: 99%

Dose optimisation during imaging in radiotherapy

Ravindran

2007

Biomed. Imaging Interv. J.

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“…Such differences manifest themselves when observing soft tissue and bone, whereas digital images can be contrast enhanced for observation. 10,11 Computed radiography (CR) is an imaging modality that, like EPID, does not require the use of hard copy film. Digital images are obtained with a photostimulable phosphor plate, replacing film, in a cassette.…”

Section: Introductionmentioning

confidence: 99%

An observer study: comparison of computed radiography to electronic and film portal imaging

Roberts

Stanley

2006

J Radiother Pract

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Introduction: Computed radiography (CR) is an imaging facility that does not require the use of hard copy film, digital images are obtained with a photostimulable phosphor plate, which replaces film, in a cassette. As the first UK radiotherapy site to trial CR, we are collecting data to assess the feasibility of using CR in radiotherapy treatment verification.Method: From 30 patients undergoing radical radiotherapy, 10 were consecutively accrued to three sites: pelvis, thorax and head and neck. Treatment verification images were taken using current protocols, but substituting standard imaging for CR images on one fraction. Four independent observers were used: two clinical oncologists and two therapy radiographers. Observers rated CR, electronic portal imaging (EPI) and enhanced contrast (EC) films of the three sites for both landmark visibility and ease of verification decision, using a numerical scoring system.Results: Ratings for visibility of landmarks and for verification decision were similar for CR and film/EPI images for most landmarks. However, CR images rated poorly compared to EC film in the head and neck region with landmarks such as thyroid cartilage and cricoid cartilage rating as 'not clear' . CR images rated better than EPI images for both visibility and verification decision on the majority of landmarks in the pelvis region.Conclusion: Results gathered from a relatively small sample size have provided the following conclusion. The visibility of landmarks in CR images is comparable to that in film and EPI. Verification of treatment images based on CR is comparable to that of the current imaging media in the department.

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“…The quality of the portal images obtained by EPID is superior to that of the images acquired by CR due to improvement of the detector and the optimization of acquisition parameters. ( 5 – 7 ) However, the resolution of the anatomical structures requires further improvement to enable more precise verification.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of the single‐shot dual‐energy subtraction technique for portal images

Fujita

Morimi

Yamaguchi

et al. 2011

J Applied Clin Med Phys

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The aim of the present study was to evaluate the clinical efficacy of the single‐shot dual‐energy subtraction technique for obtaining portal images. We prepared two storage phosphor plates for this study. A 1 mm thick tungsten sheet was placed between the two storage phosphor plates. A single use of the double‐exposure technique provides two portal images simultaneously (i.e., a standard image and a low‐contrast image), using the same patient position and with no additional radiation delivered to the patient. A bone‐enhanced image is created by image subtraction between these two images. For evaluation of clinical efficacy, three treatment sites — the brain, lung, and pelvis — were imaged. Ten sets of images were obtained for each site, and five landmarks were selected for each treatment site. The visibility of each landmark and the ease of overall verification for the selected treatment sites were assessed separately for the standard and bone‐enhanced images. Four observers consisting of one radiation oncologist and three radiation therapists participated in the present study. For most of the landmarks studied, the bone‐enhanced images were significantly superior to the standard images. Regarding the ease of overall verification, the bone‐enhanced images were significantly superior to the standard images at all sites. The p‐values of mean rating for the brain, lung, and pelvis were 0.002, 0.012, and 0.003, respectively. The bone‐enhanced images obtained using our technique increased the image quality in terms of bone visibility, and are considered useful for routine clinical practice.PACS number: 87.56.Da

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Verification of prostate treatment setup using computed radiography for portal imaging

Cited by 8 publications

References 21 publications

Dose optimisation during imaging in radiotherapy

Dose optimisation during imaging in radiotherapy

An observer study: comparison of computed radiography to electronic and film portal imaging

Effectiveness of the single‐shot dual‐energy subtraction technique for portal images

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