Marker Based IGRT in Prostate Radiotherapy - Merits and Pitfalls

Ashish, K.; Bansal, Vivek; Patel, V. C.; Bhavsar, D.; Jani, K.R.; Bhonde, Mandar; Gajjar, S.; Abraham, Aswin George

doi:10.1016/j.ijrobp.2008.06.1175

Cited by 2 publications

(7 citation statements)

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“…Similar to MVCT, implanted prostate markers could be used to facilitate the alignment process and help increase the verification accuracy. In marker-based IGRT using kVCBCT, the prostate displacement of ≥3 mm was shown in 82 out of 96 fractions and mostly in the postero-inferior direction 48 . Moreover, the prostate could be deformed to in varying degrees.…”

Section: Clinical Applications Of the Mvct And Kvcbct Systemsmentioning

confidence: 99%

“…The ability of kVCBCT to visualise soft-tissue organs was an advantage, but the boundaries of prostate, bladder and rectum were only partially differentiable. 48 Moreover, the prostate could be deformed to in varying degrees. Similar to MVCT, implanted prostate markers could be used to facilitate the alignment process and help increase the verification accuracy.…”

Section: Pelvic Regionmentioning

confidence: 99%

“…19 These uncertainties in the kVCBCT images increased again the interobserver errors during the registration process. 38,48 The result implied that there was indeed benefit in emptying the rectum before PLCT and treatment so that the prostate movement could be minimised. In marker-based IGRT using kVCBCT, the prostate displacement of !3 mm was shown in 82 out of 96 fractions and mostly in the posteroinferior direction.…”

Section: Pelvic Regionmentioning

confidence: 99%

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Image-guided radiation therapy using computed tomography in radiotherapy

Fung

2010

J Radiother Pract

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The sharp dose gradients in intensity-modulated radiation therapy increase the treatment sensitivity to various inter-and intra-fractional uncertainties, in which a slight anatomical change may greatly alter the actual dose delivered. Image-guided radiotherapy refers to the use of advanced imaging techniques to precisely track and correct these patient-specific variations in routine treatment. It can also monitor organ changes during a radiotherapy course. Currently, image-guided radiotherapy using computed tomography has gained much popularity in radiotherapy verification as it provides volumetric images with soft-tissue contrast for on-line tracking of tumour. This article reviews four types of computed tomography-based image guidance systems and their working principles. The system characteristics and clinical applications of the helical, megavoltage, computed tomography, and kilovoltage, cone-beam, computed tomography systems are discussed, given that they are currently the most commonly used systems for radiotherapy verification. This article also focuses on the recent techniques of soft-tissue contrast enhancement, digital tomosynthesis, four-dimensional fluoroscopic image guidance, and kilovoltage/megavoltage, in-line cone-beam imaging. These evolving systems are expected to take over the conventional two-dimensional verification system in the near future and provide the basis for implementing adaptive radiotherapy.

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Section: Clinical Applications Of the Mvct And Kvcbct Systemsmentioning

confidence: 99%

Section: Pelvic Regionmentioning

confidence: 99%

Section: Pelvic Regionmentioning

confidence: 99%

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Image-guided radiation therapy using computed tomography in radiotherapy

Fung

2010

J Radiother Pract

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“…The kV Xray source can be located between 80 and 100 cm from the machine isocenter, and the MV source is fixed at 100 cm from the machine isocenter. With the X-ray collimator fully open and the imager at the maximum distance from the source, the maximum field size at isocenter is 20 × 27 cm 2 .…”

Section: Hardware Localization Systemsmentioning

confidence: 99%

“…With the amount of inter-and intrafraction motion that occurs in the prostate, it is necessary to use a form of localization prior to treatment. Studies have shown that use of implanted prostate markers with kilovoltage (kV) or megavoltage (MV) imaging of localization or matching is a preferred, accurate, and reliable method for positioning prostate patients for treatment compared with laser-guided external skin alignment [1,2]. Image-guided radiation therapy (IGRT) utilizing integrated kV imaging with the linear accelerator has been performed in the Department of Radiation Oncology at Emory University since 2004.…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of Calypso^®4D Localization and Kilovoltage Image Guidance Systems for Interfraction Motion Management of Prostate Patients

Ogunleye

Rossi

Jani

et al. 2009

The Scientific World JOURNAL

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Prostate cancer represents a model site for advances in understanding inter- and intrafraction motion for radiotherapy. In this study, we examined the correlation of the electromagnetic transponder system/Calypso 4D Localization System with conventional on-board imaging (OBI) using kilovoltage imaging. Initially using a quality assurance (QA) phantom and subsequently using data of seven patients, the vector distances between Calypso- and OBI-recorded shifts were compared using the t-test. For the 30 phantom measurements, the average differences between the measured Calypso offset and the calculated OBI shift were 0.4 ± 0.4, 0.2 ± 0.3, and 0.4 ± 0.3 mm in the lateral, longitudinal, and vertical directions, respectively (p = 0.73, p = 0.91, and p = 0.99, respectively), and the average difference vector for all sessions was 0.8 ± 0.4 mm. For the 259 patient measurements, the average differences between the measured Calypso offset and the calculated OBI shift were 0.7 ± 0.5, 1.1 ± 0.9, and 1.2 ± 0.9 mm in the lateral, longitudinal, and vertical directions, respectively (p = 0.45, p = 0.28, and p = 0.56, respectively), and the average difference vector for all sessions was 2.1 ± 1.0 mm. Our results demonstrated good correlation between Calypso and OBI. While other studies have explored the issue of Calypso/OBI correlation, our analysis is unique in our use of phantom validation and in our performing the patient analysis on an initial population prior to routine setup using Calypso without OBI. Implications for Calypso's role as a QA tool are discussed.

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Marker Based IGRT in Prostate Radiotherapy - Merits and Pitfalls

Cited by 2 publications

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Image-guided radiation therapy using computed tomography in radiotherapy

Image-guided radiation therapy using computed tomography in radiotherapy

Performance Evaluation of Calypso^®4D Localization and Kilovoltage Image Guidance Systems for Interfraction Motion Management of Prostate Patients

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Marker Based IGRT in Prostate Radiotherapy - Merits and Pitfalls

Cited by 2 publications

References 0 publications

Image-guided radiation therapy using computed tomography in radiotherapy

Image-guided radiation therapy using computed tomography in radiotherapy

Performance Evaluation of Calypso®4D Localization and Kilovoltage Image Guidance Systems for Interfraction Motion Management of Prostate Patients

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Performance Evaluation of Calypso^®4D Localization and Kilovoltage Image Guidance Systems for Interfraction Motion Management of Prostate Patients