Interactive use of on-line portal imaging in pelvic radiation

Neve, Wilfried De; Heuvel, Frank Van den; Coghe, M.; Verellen, Dirk; Beukeleer, M. De; Roelstraete, A.; Roover, P. De; Thon, L.; Storme, Guy

doi:10.1016/0360-3016(93)90075-7

Cited by 75 publications

(37 citation statements)

References 8 publications

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“…Pelvic fields have been the subject of several studies of positioning accuracy (7,(11)(12)(13)23), since in general surveys of positioning accuracy (8,22) the pelvis was shown to be a site of relatively large errors, and because the pelvis is a site of high-dose curative treatment with the presence of * The mean values of the differences between the position of the respective points, or of the field size, in the simulation and treatment images (SIM-MV), the standard deviation (SD), the systematic variations, and the random variations. A negative value of a mean SIM-MV difference represents a mean shift of that point in the MV images in the right lateral (x) or cranial (y) direction.…”

Section: Discussionmentioning

confidence: 99%

“…Errors were larger when a mattress was used and with increasing patient diame ter. In a study of on-line portal imaging by De Neve et al (11), 566 parallel opposed pelvic fields were evaluated in 13 patients. Portal images were immediately evaluated and, whenever a visible error was detected, corrective table ad justments were applied using a telecontrolled patient couch.…”

Section: Discussionmentioning

confidence: 99%

“…results of De Neve et a l (11), who found a significantly higher accuracy for a positioning technique in which a longitudinal laser line and the lower field border were matched, a second pilot study was set up. Four patients were positioned without the special device using long laser lines and marking of the caudal field border.…”

Section: Large Pelvic Fields Fo R Gynecological Cancermentioning

confidence: 99%

“…For the gynecological fields, accuracy obviously was worse, which is a common finding. Posi tioning accuracy diminishes with increasing patient weight (11,13,23). The field center is located in an area susceptible to movement (respiration, loose abdominal wall), and alignment often proves to be difficult.…”

Section: Immobilizationmentioning

confidence: 99%

See 3 more Smart Citations

A quality control study of the accuracy of patient positioning in irradiation of pelvic fields

Creutzberg

Althof

Hoog

et al. 1996

International Journal of Radiation Oncology*Biology*Physics

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Large Pelvic Fields Fo R Gynecological Cancermentioning

confidence: 99%

Section: Immobilizationmentioning

confidence: 99%

See 2 more Smart Citations

A quality control study of the accuracy of patient positioning in irradiation of pelvic fields

Creutzberg

Althof

Hoog

et al. 1996

International Journal of Radiation Oncology*Biology*Physics

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“…If the right dose per fi'action is used, the normal tissue will recover better in between the fractions than the tumor. As a consequence, a radiation treatment can consist of over 30 fractions and can last 2 months.…”

Section: Radiotherapymentioning

confidence: 99%

Safety margins for geometrical uncertainties in radiotherapy

Stroom

2000

Med. Phys.

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In this thesis we deal with the calculation and minimization of safety margins (CTV to PTV) that are required to account for setup errors and internal organ motion in radiotherapy. First of all, an algorithm was developed to automatically expand a three‐dimensional (3‐D) tumor volume, defined in a set of 2‐D CT images, with 3‐D margins of a given size. To do this manually and in three dimensions is impossible. The clinical advantages of the automatically calculated 3‐D margins over the much applied manual 2‐D expansion procedure were assessed. In addition, a model was devised to calculate the margins using measured geometrical deviations from the planned situation in representative patient populations. The calculated margins were such that the expected radiation dose in the tumor was adequate and homogeneous. It appeared that systematic deviations, which are the same each fraction of the treatment, are about three times more important than random deviations, which vary from fraction to fraction. The model was used to investigate whether smaller margins could be used when patients with prostate cancer are treated in the prone instead of the supine position, but there was no significant difference. Finally, the use of portal images for an on‐line correction of geometrical deviations was studied. The registration of bony structures in the images enabled on‐line corrections of the patient setup within a couple of minutes and a significant margin reduction. For prostate cancer treatments, simulations using multiple CT data of 15 patients indicated that gas pockets in the rectum, which are also visible in portal images, may be used for the on‐line determination of rectal wall and tumor motion.

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A minimax entropy registration framework for patient setup verification in radiotherapy

Bansal

Staib

Chen

et al. 1999

Comput. Aided Surg.

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In external beam radiotherapy (EBRT), patient setup verification over the entire course of fractionated treatment is necessary for accurate delivery of a specified dose to the tumor. We are working on the development of a minimax entropy registration framework for patient setup verification using dual portal images and the treatment planning 3D CT dataset. In this paper, we present an overview of our registration framework, where an iteratively and automatically estimated segmentation of the portal image is utilized to more accurately and robustly register the portal image to the 3D treatment-planning CT data. In addition, we describe initial testing of this approach. We note that, due to low resolution and low contrast of the portal images, this registration presents a difficult problem. We also note that the registration of the images in our proposed method is guided by the bony structure visible in the portal and the 3D CT images. However, since the prostate can move with respect to the pelvic bone, we propose using ultrasound images to quantify this movement.

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Interactive use of on-line portal imaging in pelvic radiation

Cited by 75 publications

References 8 publications

A quality control study of the accuracy of patient positioning in irradiation of pelvic fields

A quality control study of the accuracy of patient positioning in irradiation of pelvic fields

Safety margins for geometrical uncertainties in radiotherapy

A minimax entropy registration framework for patient setup verification in radiotherapy

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