Is it necessary to repeat quality control procedures for head and neck patients?

Mitine, C.; Leunens, G.; Verstraete, J.; Blanckaert, N.; Dam, J. Ban; Dutreix, A.; Schueren, E. Ban der

doi:10.1016/0167-8140(91)90038-i

Cited by 79 publications

(16 citation statements)

References 17 publications

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“…This is consistent with a study by Mitine et al who showed that most errors in head and neck patient set‐up were diagnosed from the first portal film. 27 …”

Section: Methodsmentioning

confidence: 99%

“…This is consistent with a study by Mitine et al who showed that most errors in head and neck patient set-up were diagnosed from the first portal film. 27 The determination of the 'variable initial action value' (t ) for the head and neck and prostate treatments was chosen to be twice the standard deviation of the random uncertainty following the original paper by Bel et al 24 If an error was diagnosed in the 'Amsterdam' model, the patient was to be shifted by the magnitude of the detected dislocation.…”

Section: Decision Models 'Amsterdam' Modelmentioning

confidence: 99%

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Decision‐making models in the analysis of portal films: A clinical pilot study

See

Kron

Johansen

et al. 2000

Australasian Radiology

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Portal films continue to play an important role in the verification of radiotherapy treatment. There is still some discussion, however, as to what action should be taken after a port film has shown a radiation field deviation from the prescribed volume. It was the aim of the present pilot study to investigate the performance of three decision-making models ('Amsterdam', 'Quebec' and 'Newcastle') and an expert panel basing their decision on intuition rather than formal rules after portal film acquisition in a clinical setting. Portal films were acquired on every day during the first week of treatment for five head and neck and five prostate cancer patients (diagnostic phase). If required, the field position was modified according to our normal practice following the recommendation of the expert panel. In order to analyse the results of the models, however, additional port films were taken in the following 3 treatment weeks with the patient moved as required by the different models (intervention phase). The portal films were taken over 4 consecutive days, positioning the patient according to each of the different models on one day each. None of the models diagnosed a field misplacement in the head and neck patients, while the 'Amsterdam' and 'Quebec' models predicted a move in one prostate patient. The 'Newcastle' model, which is based on Hotelling's T2 statistic, proved to be more sensitive and diagnosed a systematic displacement for three prostate patients. The intervention phase confirmed the diagnosis of the model, even if the three portal films taken with the patient position adjusted as required by the model proved to be insufficient to demonstrate an improvement. The 'Newcastle' model does not rely on assumptions about the random movement of patients and requires five portal films before a decision can be reached. This approach lends itself well to incorporation into electronic portal imaging 'packages', where repeated image acquisitions present no logistical difficulty.

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“…This is consistent with a study by Mitine et al who showed that most errors in head and neck patient set‐up were diagnosed from the first portal film. 27 …”

Section: Methodsmentioning

confidence: 99%

Section: Decision Models 'Amsterdam' Modelmentioning

confidence: 99%

Decision‐making models in the analysis of portal films: A clinical pilot study

See

Kron

Johansen

et al. 2000

Australasian Radiology

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“…In recent years in a number of centres in vivo dosimetry became a routine, common method of quality-beam assurance for checking the precision of irradiation (3,5,6).…”

Section: Original Articlementioning

confidence: 99%

“…This could also be the reason for serious discrepancies between delivered and planned doses. In vivo dosimetry performed twice during the treatment-at the first fraction and then during the treatment-is a useful way of quantifying the error in dose delivery (1)(2)(3)(4)(5)(6).…”

Section: Original Articlementioning

confidence: 99%

Evaluation of Delivered Dose Changes During Radiation Therapy

Miszczyk

Wydmański²

1999

Acta Oncologica

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The influence of changes in the thickness of the irradiated tissue block during radiotherapy on the error in dose delivery was assessed by dosimetry in vivo. In 55 cases of head and neck cancers, entrance and exit doses and the irradiated volume sizes were measured during the first and the twentieth fractions. The real and hypothetical midline doses (i.e. midline doses calculated when the entrance dose is considered as a planned one) were calculated. The average size of irradiated volume was smaller after 20 fractions. The mean of midline dose dosimetric errors during the twentieth fraction was larger (overdosage) than that during the first fraction. These means were compared and statistically significant differences were found. Our results confirm the value of in vivo dosimetry as an appropriate tool for detecting errors in delivered dose provoked by changes in irradiated volume dimensions and show the necessity to check irradiated volume thickness during the treatment.

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“…[2][3][4][5][6][7][8][9][10][11][12][13] However, only a few centers have developed verification procedures of patient setup and applied them on a regular basis. [14][15][16][17][18][19][20][21][22][23] The great improvement in tumor localization due to the development of imaging modalities such as computerized tomography and magnetic resonance imaging has initiated a trend toward tighter target volumes which is potentially dangerous without accurate field placement. This creates a strong need for daily on-line verifications in modern radiotherapy.…”

Section: Introductionmentioning

confidence: 99%

Automatic setup deviation measurements with electronic portal images for pelvic fields

et al. 1998

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The purpose of this work was to develop a fully automatic tool for the detection of setup deviation for small pelvic field using, in external beam radiotherapy, an electronic portal imaging device (EPID). The algorithm processes electronic portal images of prostate cancer patients. No fiducial points or user interventions are needed. Deviation measurements are based on bone edge detection performed with Laplacian of a Gaussian (LoG) operator. Two bone edge images are then correlated, one of which is a reference image taken as the first fraction image for the purpose of this study. The electronic portal images (EPI) also show band artefacts which are removed using the morphological top-hat transform. The algorithm was first validated with 59 phantom images acquired in clinical treatment conditions with known displacements. The algorithm was then validated with 79 clinical images where bone contours were delineated manually. For the phantom images, the setup deviations were measured with a absolute mean error of 0.59 mm and 0.47 mm with a standard deviation of 0.64 mm and 0.42 mm, horizontally and vertically, respectively. A second validation was performed using clinical prostate cancer images. The measured patient displacements have an absolute mean error of 0.48 mm and 1.41 mm with a standard deviation of 0.58 mm and 1.30 mm in the X and Y directions, respectively. The algorithm execution time on a SUN workstation is 5 s. This algorithm shows good potential as a setup deviation measurement tool in clinical practice. The possibility of using this algorithm combined with decision rules based on statistical observations is very promising.

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Is it necessary to repeat quality control procedures for head and neck patients?

Cited by 79 publications

References 17 publications

Decision‐making models in the analysis of portal films: A clinical pilot study

Decision‐making models in the analysis of portal films: A clinical pilot study

Evaluation of Delivered Dose Changes During Radiation Therapy

Automatic setup deviation measurements with electronic portal images for pelvic fields

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