A case study of radiotherapy planning for a bilateral metal hip prosthesis prostate cancer patient

Su, Andy; Reft, Chester S.; Rash, Carla; Price, Jennifer; Jani, Ashesh B.

doi:10.1016/j.meddos.2005.06.001

Cited by 32 publications

(22 citation statements)

References 14 publications

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“…For each map, the dose increases at the interface between Ti and Nylon‐12 on the proximal side and decreases in the distal region of the prosthesis. This is due to electrons backscattering from the interface into the incoming beam direction and attenuation of the photon beam in the prosthesis respectively 1, 3, 7, 8, 11, 28…”

Section: Resultsmentioning

confidence: 99%

“…There is dose enhancement at the proximal side of the prosthesis and dose reduction in the distal region relative to the bony structure alone. The dose enhancement depicted by the peak at the proximal side is due to electron backscatter at the tissue–prosthesis interface, while the dose reduction on the distal side of the prosthesis is due to attenuation of the primary beam passing through it 1, 3, 7, 8, 11, 28…”

Section: Resultsmentioning

confidence: 99%

“…The majority of hip prostheses are composed of Co‐Cr alloys as they are considered to have the best combination of corrosion, fatigue resistance, and mechanical strength 5. The high Z and high density of metallic prostheses relative to water yield challenges for radiotherapy dose computation when beams pass through these devices because the dose attenuation through a prosthetic device during pelvic irradiation could be significant 2, 5, 6, 7, 8, 9, 10. In addition, the drastic changes in electron scattering characteristics near interfaces due to sudden and extreme changes in density are also challenging for most dose calculation algorithms that are not Monte Carlo (MC) or Acuros as MC and Acuros algorithms can account for the effects of heterogeneities in patient dose calculation.…”

Section: Introductionmentioning

confidence: 99%

“…It is understood that the scientific understanding and approach of clinical dosimetry for the presence of metallic prostheses during irradiation of pelvic malignancies is still a challenge 2, 9, 10. Also, the dose perturbation due to these prostheses could affect clinical outcome due to its significance and so it cannot be ignored 7, 8. As a result, it is necessary to expand the information available in literature with current data which is the motivation of the present study.…”

Section: Introductionmentioning

confidence: 99%

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Dose comparison between Gafchromic film, XiO, and Monaco treatment planning systems in a novel pelvic phantom that contains a titanium hip prosthesis

Ade

Plessis

2017

J Applied Clin Med Phys

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The presence of metallic prostheses during external beam radiotherapy of malignancies in the pelvic region has the potential to strongly influence the dose distribution to the target and to tissue surrounded by the prostheses. This study systematically investigates the perturbation effects of unilateral titanium prosthesis on 6 and 15 MV photon beam dose distributions using Gafchromic EBT2 film measurements in a novel pelvic phantom made out of a stack of nylon slices. Comparisons were also made between the film data and dose calculations made on XiO and Monaco treatment planning systems. The collapsed cone algorithm was chosen for the XiO and the Monte Carlo algorithm used on Monaco is XVMC. Transmission measurements were taken using a narrow‐beam geometry to determine the mass attenuation coefficient of nylon = 0.0458 cm2/g and for a water‐equivalent RW3 phantom, it was 0.0465 cm2/g. The perturbation effects of the prosthesis on dose distributions were investigated by measuring and comparing dose maps and profiles. The magnitude of dose perturbations was quantified by calculating dose enhancement and reduction factors using field sizes of 3 × 3, 5 × 5, 10 × 10, and 15 × 15 cm2. For the studied beams and field sizes, dose enhancements between 21 and 30% and dose reductions between 15 and 21% were observed at the nylon‐prosthesis interface on the proximal and distal sides of the prosthesis for film measurements. The dose escalation increases with beam energy, and the dose reduction due to attenuation decreases with increasing beam energy when compared to unattenuated beam data. A comparison of film and XiO depth doses for the studied fields gave relative errors between 1.1 and 23.2% at the proximal and distal interfaces of the Ti prosthesis. Also, relative errors < 4.0% were obtained between film and Monaco dose data outside the prosthesis for 6 and 15 MV lateral opposing fields.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dose comparison between Gafchromic film, XiO, and Monaco treatment planning systems in a novel pelvic phantom that contains a titanium hip prosthesis

Ade

Plessis

2017

J Applied Clin Med Phys

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“…Other researchers have investigated the use of IMRT in metallic implants as well. 8 Over the last 5 years, the use of volumetric modulated arc therapy (VMAT) systems has gained traction in the field of prostate cancer RT. VMAT system is a rotational IMRT, which allows the simultaneous variation of gantry rotation speed, dose rate, and multi leaf collimator field aperture.…”

Section: Introductionmentioning

confidence: 99%

Volumetric modulated arc therapy in prostate cancer patients with metallic hip prostheses in a UK centre

Brunt

Temple

et al. 2015

Reports of Practical Oncology & Radiotherapy

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An additional tilted‐scan‐based CT metal‐artifact‐reduction method for radiation therapy planning

Kim

Pua

Lee

et al. 2018

J Applied Clin Med Phys

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PurposeAs computed tomography (CT) imaging is the most commonly used modality for treatment planning in radiation therapy, metal artifacts in the planning CT images may complicate the target delineation and reduce the dose calculation accuracy. Although current CT scanners do provide certain correction steps, it is a common understanding that there is not a universal solution yet to the metal artifact reduction (MAR) in general. Particularly noting the importance of MAR for radiation treatment planning, we propose a novel MAR method in this work that recruits an additional tilted CT scan and synthesizes nearly metal‐artifact‐free CT images.MethodsThe proposed method is based on the facts that the most pronounced metal artifacts in CT images show up along the x‐ray beam direction traversing multiple metallic objects and that a tilted CT scan can provide complementary information free of such metal artifacts in the earlier scan. Although the tilted CT scan would contain its own metal artifacts in the images, the artifacts may manifest in a different fashion leaving a chance to concatenate the two CT images with the metal artifacts much suppressed. We developed an image processing technique that uses the structural similarity (SSIM) for suppressing the metal artifacts. On top of the additional scan, we proposed to use an existing MAR method for each scan if necessary to further suppress the metal artifacts.ResultsThe proposed method was validated by a simulation study using the pelvic region of an XCAT numerical phantom and also by an experimental study using the head part of the Rando phantom. The proposed method was found to effectively reduce the metal artifacts. Quantitative analyses revealed that the proposed method reduced the mean absolute percentages of the error by up to 86% and 89% in the simulation and experimental studies, respectively.ConclusionsIt was confirmed that the proposed method, using complementary information acquired from an additional tilted CT scan, can provide nearly metal‐artifact‐free images for the treatment planning.

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A case study of radiotherapy planning for a bilateral metal hip prosthesis prostate cancer patient

Cited by 32 publications

References 14 publications

Dose comparison between Gafchromic film, XiO, and Monaco treatment planning systems in a novel pelvic phantom that contains a titanium hip prosthesis

Dose comparison between Gafchromic film, XiO, and Monaco treatment planning systems in a novel pelvic phantom that contains a titanium hip prosthesis

Volumetric modulated arc therapy in prostate cancer patients with metallic hip prostheses in a UK centre

An additional tilted‐scan‐based CT metal‐artifact‐reduction method for radiation therapy planning

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