Investigation of the radiation dose from cone‐beam <scp>CT</scp> for image‐guided radiotherapy: A comparison of methodologies

Buckley, Jarryd; Wilkinson, Dean; Malaroda, Alessandra; Metcalfe, Peter E

doi:10.1002/acm2.12239

Cited by 30 publications

(19 citation statements)

References 29 publications

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“…The central and peripheral dose measurements were weighted as follows:

D_{w} = \frac{1}{3} D_{c} + \frac{2}{3} \bar{D_{p}}

where

D_{c}

is the measurement at the center of the cylinder and

\bar{D_{p}}

is the average over measurements at four cardinal peripheral locations (in units of mGy). The methodology is consistent with the AAPM Task Group 111 guidelines outlined by Buckley et al and similar to CBCT dose measurements of the head and body by others in literature. The measurements also included additional scatter material placed inferior and superior to the phantom, consistent with the recommendations by Amer et al The

D_{w}

value is analogous to the

{CTDI}_{w}

value in MDCT, recognizing fundamental differences between the two technologies with respect to helical motion and extent of the volumetric beam.…”

Section: Methodssupporting

confidence: 80%

Cone‐beam CT dose and imaging performance evaluation with a modular, multipurpose phantom

et al. 2019

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Purpose A modular phantom for dosimetry and imaging performance evaluation in cone‐beam computed tomography (CBCT) is reported, providing a tool for quantitative technical assessment that can be adapted to a broad variety of CBCT imaging configurations and clinical applications. Methods The phantom presents a set of modules that can be ordered in various configurations suitable to a particular CBCT system. Modules include slabs containing a uniform medium, low‐contrast inserts, line‐spread features, and disk features suitable to measurement of image uniformity, noise, noise‐power spectrum (NPS), contrast, contrast‐to‐noise ratio (CNR), Hounsfield (HU) accuracy, linearity, spatial resolution modulation transfer function (MTF), and magnitude of cone‐beam artifact. Automated software recognizes the phantom configuration in DICOM images and provides structured reporting of such test measures. In any modular configuration, the phantom permits measurement of air kerma in central and peripheral locations with an air ionization chamber (e.g., Farmer chamber). The utility and adaptability of the phantom were demonstrated across a spectrum of CBCT systems, including scanners for orthopaedic imaging (Carestream OnSight 3D, Rochester NY), breast imaging (Doheny prototype, UC Davis), image‐guided surgery (IGS, Medtronic O‐arm, Littleton MA), angiography (Siemens Artis Zeego, Forcheim Germany), and image‐guided radiation therapy (IGRT, Elekta Synergy XVI, Stockholm Sweden). Results The phantom provided a consistent platform for quantitative assessment of dose and imaging performance compatible with a broad spectrum of CBCT systems. The purpose of the survey was not to obtain head‐to‐head performance comparison of systems designed for such distinct clinical applications. Rather, the survey demonstrated the suitability of the phantom to a broad spectrum of systems in a manner that provides characterization pertinent to disparate applications and imaging tasks. For example: the orthopaedic CBCT system (pertinent clinical tasks relating to high‐resolution bone imaging) was shown to achieve MTF consistent with imaging of high‐contrast trabecular bone structures (i.e., the MTF reduced to 10% at spatial frequency, f10 = 1.2 mm−1); the breast system (even higher‐resolution imaging of microcalcifications) exhibited f10 = 2.2 mm−1; the IGS system (tasks including both bone and soft‐tissue contrast resolution) provided f10 = 0.9 mm−1 and soft‐tissue CNR = 1.64; the angiography system (soft‐tissue body interventions) demonstrated CNR = 1.2 in soft tissues approximating liver lesions; and the IGRT system (pertinent tasks emphasizing HU linearity and image uniformity) showed linear response with HU values (R2 = 1), with a cupping artifact (tcup = 5.8%) due to x‐ray scatter. Conclusions The phantom provides an adaptable, quantitative basis for CBCT dosimetry and imaging performance evaluation suitable to a broad variety of CBCT systems. The dosimetry and image quality metrics are consistent with up‐to‐date methods for rigorous, quantitative,...

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“…The central and peripheral dose measurements were weighted as follows:

D_{w} = \frac{1}{3} D_{c} + \frac{2}{3} \bar{D_{p}}

where

D_{c}

is the measurement at the center of the cylinder and

\bar{D_{p}}

D_{w}

value is analogous to the

{CTDI}_{w}

value in MDCT, recognizing fundamental differences between the two technologies with respect to helical motion and extent of the volumetric beam.…”

Section: Methodssupporting

confidence: 80%

Cone‐beam CT dose and imaging performance evaluation with a modular, multipurpose phantom

et al. 2019

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“…Potential drawbacks of the proposed CT method for urethral localization include the double scanning used, which requires imaging both before and after contrast injection, doubling the radiation exposure to the patient from imaging studies. Pelvic CBCT is associated with a dose of 20-30 mGy per scan [32]. This could result, together with the CT simulation, in a radiation dose of 0.24-0.36 Gy from imaging for a course of 5 fractions SBRT, compared to 0.12-0.18 Gy in the current practice.…”

Section: Discussionmentioning

confidence: 99%

Automatic localization of the prostatic urethra for image guided radiation therapy

Nasser

Klein

Fenig

et al. 2021

Technical Innovations & Patient Support in Radiation Oncolo

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Treatment of prostate cancer with radiation therapy (RT) requires image guided RT (IGRT) to focus the radiation on the target volumes while minimizing doses to organs at risk. Here we describe a urinary catheter that allows imaging of the prostatic urethra and uses it for automatic localization of the prostate for IGRT. The catheter has a contrast lumen that can be empty or full with contrast. Computerized tomography is performed twice, with contrast lumen empty and full, allowing urethral autosegmentation using digital subtraction. Under ultrasound, continuous urethral visualization is possible by pumping aerated gel in-and out of the contrast lumen.

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“…For daily imaging, there are three possibilities: In-room CT, cone beam CT (CBCT) or on-board MR imaging. The use of in-room CT currently guarantees the most accurate definition of proton stopping power, and with a low-dose protocol, it is possible to limit the imaging dose to the patient to below 1 mGy per CT [23,24], similar to that delivered with CBCT [25]. CBCT for adaption is currently under investigation but extracting density information with the same accuracy as with CT [26][27][28][29][30] remains challenging.…”

Section: Patientmentioning

confidence: 99%

Daily adaptive proton therapy – the key to innovative planning approaches for paranasal cancer treatments

et al. 2019

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Investigation of the radiation dose from cone‐beam CT for image‐guided radiotherapy: A comparison of methodologies

Cited by 30 publications

References 29 publications

Cone‐beam CT dose and imaging performance evaluation with a modular, multipurpose phantom

Cone‐beam CT dose and imaging performance evaluation with a modular, multipurpose phantom

Automatic localization of the prostatic urethra for image guided radiation therapy

Daily adaptive proton therapy – the key to innovative planning approaches for paranasal cancer treatments

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