High-precision prostate cancer irradiation by clinical application of an offline patient setup verification procedure, using portal imaging

Bel, Arjan; Vos, Petra J.E.; Rodrigus, P.; Creutzberg, Carien L.; Visser, A.G.; Stroom, J.; Lebesque, Joos V.

doi:10.1016/0360-3016(95)02395-x

Cited by 196 publications

(81 citation statements)

References 24 publications

(1 reference statement)

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“…Online and offline corrections are helpful to eliminate set-up uncertainties and to reduce systematic errors. 23,28,29 In the present study, both the systematic and the random errors for SV and rotation values were relatively lower than the other reports. This may be due to the fact that we follow a strict bladder and rectum preparation protocol before the planning CT and during the treatment course.…”

Section: Discussioncontrasting

confidence: 77%

Evaluation of Interfractional Movement of the Seminal Vesicle and Dose Variations with IGRT Throughout the Prostate Cancer Radiotherapy.

Ergen¹

2016

UHOD

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To validate the actual cumulative doses delivered to the seminal vesicle (SV) depending on the organ movement using kV-Cone Beam CT (kV-CBCT) datasets acquired during prostate image-guided radiation therapy. Ten patients with intermediate risk prostate cancer treated with IMRT were included in this study. Both the prostate and the first 2 cm of the SV were included in the CTV. PTV margin was 8 mm in all directions except posterior, where it was 5 mm. Sixteen kV-CBCT scans per patient were used for assessments. After each kV-CBCT was matched with the planning CT based on prostate, the SV were recontoured as proximal, distal SV and both of them together (the whole SV). Actual delivered doses to the SV were assessed by means of DVH. The variations in certain dosevolume parameters were analyzed using the Student's test. Systematic and random errors of the SV and margins were assessed using the van-Herk formula. We observed that the SV movement in the anterior-posterior direction was significantly more compared to superior-inferior and left-right direction. The dose volume variations for the whole SV (D98%, D50%, D2%) and the distal SV (D98%, D95%, D50%) were significantly different than the planned doses. However, both the whole SV and the distal SV received the prescribed dose. Although it seems that there is a need to give larger margin to the SV in posterior direction, the actual cumulative doses delivered to SV throughout the treatment were within the prescribed dose.Keywords: Image guided radiation therapy, Interfraction motions, kV-CBCT, Prostate cancer, Seminal vesicle ÖZET Prostat kanseri Radyoterapisi Sırasında Fraksiyonlar Arası Seminal Vezikül Hareketleri ve Doz Değişimlerinin IGRT ile DeğerlendirilmesiBu çalışmanın amacı, kV-Cone Beam CT (kV-CBCT) ile görüntü kılavuzluğunda prostat kanseri radyoterapisinde organ hareketine bağlı olarak seminal veziküllerin aldığı kümülatif dozların doğruluğunun değerlendirilmesidir. Çalışmamıza IMRT tekniği ile tedavi edilmiş orta risk prostat kanserli on hasta dahil edilmiştir. Prostat ve seminal vesiküllerin ilk 2 cm'lik bölümü CTV'ye dahil edilmiştir. Prostat ve SV'e posterior yönden 5 mm, diğer yönlerden 8 mm PTV marjı verilmiştir. Her hastadan 16 kV-CBCT alınmış ve SV'ye verilen marjın yeterli olup olmadığını saptamak için seçilen kV-CBCT görüntüleri ile planlama BT görüntüleri prostat referans alınarak offline eşleştirilmiştir. Seminal veziküller, proksimal-distal SV şeklinde ayrı ayrı ve her ikisi birlikte tüm SV olacak şekilde yeniden konturlanmıştır. Seminal veziküllerin aldığı doz DVH yardımı ile değerlendirilmiştir. Doz volüm histogramındaki değişiklikler Student test ile analiz edilmiştir. Sistematik ve random hatalar van-Herk formülü ile değerlendirilerek gerekli emniyet marjları bulunmuştur. Seminal vezikül hareketinin alt-üst ve sağ-sol yöne kıyasla ön-arka eksende daha fazla olduğu görülmüştür. Tüm SV için (D98% D50,% D2%) ve distal SV için doz volüm değişiklikleri (D98% D95,% D50%) planlanan dozlardan önemli ölçüde farklı bulunmuştur. Bununla bir...

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Section: Discussioncontrasting

confidence: 77%

Evaluation of Interfractional Movement of the Seminal Vesicle and Dose Variations with IGRT Throughout the Prostate Cancer Radiotherapy.

Ergen¹

2016

UHOD

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“…These two parameters were frequently used in investigating set-up accuracy in radiotherapy. [8][9][10][11][12] For each patient, an average systematic error was calculated by averaging the set-up errors in all fractions of a treatment course. For patients within the same body region, a group systematic error was calculated and denoted by +.…”

Section: Methodsmentioning

confidence: 99%

Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

Cheng¹,

Wu²

2014

BJR

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Objective: Effective immobilization is crucial for the accurate delivery of radiotherapy. This study aimed to compare the effectiveness of the commonly used immobilization systems for different body regions using megavoltage CT (MVCT). Methods: Daily treatment set-up data from 212 patients treated by helical tomotherapy (Accuray, Sunnyvale, CA) in 6 body regions (52 head and neck, 41 chest, 38 abdomen, 36 pelvis, 18 breast and 27 cranium) were obtained. Based on a verification tool using the pretreatment MVCT, set-up corrections for each patient were recorded. Mean systematic and random errors of lateral, longitudinal, vertical and roll directions and threedimensional vectors were compared between immobilization systems of each region. Results: Smaller set-up deviations were observed in the Orfit system (Orfit Industries NV, Wijnegem, Belgium) of the head and neck region, while the performance of immobilization systems for the chest, abdomen and pelvis regions was similar. Larger differences were noted in the breast group, where the prone BodyFIX® system

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“…A reproducibility of ±0.5% of the pixel values of ROI has been determined from our measurements using equation (3). Different parameter settings will cause slightly different reproducibility values due to the variable noise level (not investigated in detail in the current work).…”

Section: Reproducibility Of the Bis 710mentioning

confidence: 99%

“…Since their inception, most on-line portal imaging studies have concentrated on verification of set up geometries, such as the radiation beam size, shape and location relative to anatomical structures 1,2,3,4,5 . In the last few years, their potential for dosimetric purposes was investigated.…”

Section: Introductionmentioning

confidence: 99%

Assessment of flatness and symmetry of megavoltage x-ray beam with an electronic portal imaging device (EPID)

Liu

Doorn

Bezak

2002

Australas. Phys. Eng. Sci. Med.

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The input/output characteristics of the Wellhofer BIS 710 electronic portal imaging device (EPID) have been investigated to establish its efficacy for periodic quality assurance (QA) applications. Calibration curves have been determined for the energy fluence incident on the detector versus the pixel values. The effect of the charge coupled device (CCD) camera sampling time and beam parameters (such as beam field size, dose rate, photon energy) on the calibration have been investigated for a region of interest (ROI) around the central beam axis. The results demonstrate that the pixel output is a linear function of the incident exposure, as expected for a video-based electronic portal imaging system. The field size effects of the BIS 710 are similar to that of an ion chamber for smaller field sizes up to 10 x 10 cm 2 . However, for larger field sizes the pixel value increases more rapidly. Furthermore, the system is slightly sensitive to dose rate and is also energy dependent. The BIS 710 has been used in the current study to develop a QA procedure for measurements of flatness and symmetry of a linac x-ray beam. As a two-dimensional image of the radiation field is obtained from a single exposure of the BIS 710, a technique has been developed to calculate flatness and symmetry from a defined radiation area. The flatness and symmetry values obtained are different from those calculated conventionally from major axes only (inplane, crossplane). This demonstrates that the technique can pick up the "cold" and "hot" spots in the analysed area, providing thus more information about the radiation beam. When calibrated against the water tank measurements, the BIS 710 can be used as a secondary device to monitor the x-ray beam flatness and symmetry.

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High-precision prostate cancer irradiation by clinical application of an offline patient setup verification procedure, using portal imaging

Cited by 196 publications

References 24 publications

Evaluation of Interfractional Movement of the Seminal Vesicle and Dose Variations with IGRT Throughout the Prostate Cancer Radiotherapy.

Evaluation of Interfractional Movement of the Seminal Vesicle and Dose Variations with IGRT Throughout the Prostate Cancer Radiotherapy.

Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

Assessment of flatness and symmetry of megavoltage x-ray beam with an electronic portal imaging device (EPID)

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