A planning study for palliative spine treatment using StatRT and megavoltage CT simulation

Rong, Yi; Yadav, Poonam; Paliwal, Bhudatt R.; Shang, Luning; Welsh, James S.

doi:10.1120/jacmp.v12i1.3348

Cited by 8 publications

(6 citation statements)

References 30 publications

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“…Improvements of contouring and planning accuracy are expected by the application of MV-CTs or dual energy CT for planning, as well as by advancing dose calculation and metal artifact reduction algorithms. 1,6,14,[19][20][21][22][23][24] Recent developments in neurosurgery, the introduction of carbon-fiber-reinforced Polyetheretherketone (CFR-PEEK, or CFP for short) pedicle screw systems, may "solve" or at least improve the prescribed concerns in the future. [25][26][27][28] Dependent on the system and manufacturer, CFP systems feature a remarkably reduced amount of titanium or no metallic components, and thus decrease the impact of several correlated uncertainties.…”

Section: Introductionmentioning

confidence: 99%

The dosimetric impact of stabilizing spinal implants in radiotherapy treatment planning with protons and photons: standard titanium alloy vs. radiolucent carbon‐fiber‐reinforced PEEK systems

Müller

Ryang

Oechsner

et al. 2020

J Applied Clin Med Phys

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Background: Throughout the last years, carbon-fibre-reinforced PEEK (CFP) pedicle screw systems were introduced to replace standard titanium alloy (Ti) implants for spinal instrumentation, promising improved radiotherapy (RT) treatment planning accuracy. We compared the dosimetric impact of both implants for intensity modulated proton (IMPT) and volumetric arc photon therapy (VMAT), with the focus on uncertainties in Hounsfield unit assignment of titanium alloy. Methods: Retrospective planning was performed on CT data of five patients with Ti and five with CFP implants. Carbon-fibre-reinforced PEEK systems comprised radiolucent pedicle screws with thin titanium-coated regions and titanium tulips. For each patient, one IMPT and one VMAT plan were generated with a nominal relative stopping power (SP) (IMPT) and electron density (ρ) (VMAT) and recalculated onto the identical CT with increased and decreased SP or ρ by AE6% for the titanium components. Results: Recalculated VMAT dose distributions hardly deviated from the nominal plans for both screw types. IMPT plans resulted in more heterogeneous target coverage, measured by the standard deviation σ inside the target, which increased on average by 7.6 AE 2.3% (Ti) vs 3.4 AE 1.2% (CFP). Larger SPs lead to lower target minimum doses, lower SPs to higher dose maxima, with a more pronounced effect for Ti screws. Conclusions: While VMAT plans showed no relevant difference in dosimetric quality between both screw types, IMPT plans demonstrated the benefit of CFP screws through a smaller dosimetric impact of CT-value uncertainties compared to Ti. Reducing metal components in implants will therefore improve dose calculation accuracy and lower the risk for tumor underdosage.

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Section: Introductionmentioning

confidence: 99%

The dosimetric impact of stabilizing spinal implants in radiotherapy treatment planning with protons and photons: standard titanium alloy vs. radiolucent carbon‐fiber‐reinforced PEEK systems

Müller

Ryang

Oechsner

et al. 2020

J Applied Clin Med Phys

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“…For example, subtraction artifacts and beam hardening artifacts can be manually contoured, and the Hounsfield unit (HU) value changed within the planning system to a number more reflective of the actual tissue density present. When and where possible, such artifacts may even be avoidable through use of megavoltage CT for treatment planning (though the benefit here should be carefully weighed against the additional considerations that would be introduced, relating largely to overall image quality) . Furthermore, use of higher energy beams can also be advantageous in these situations since they have improved ratios of Compton to photoelectric effect.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric Consequences of Using Contrast‐enhanced Computed Tomographic Images for Intensity‐modulated Stereotactic Body Radiotherapy Planning

Yoshikawa

Roback

LaRue

et al. 2015

Vet Radiology Ultrasound

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Potential benefits of planning radiation therapy on a contrast-enhanced computed tomography scan (ceCT) should be weighed against the possibility that this practice may be associated with an inadvertent risk of overdosing nearby normal tissues. This study investigated the influence of ceCT on intensity-modulated stereotactic body radiotherapy (IM-SBRT) planning. Dogs with head and neck, pelvic, or appendicular tumors were included in this retrospective cross-sectional study. All IM-SBRT plans were constructed on a pre- or ceCT. Contours for tumor and organs at risk (OAR) were manually constructed and copied onto both CT's; IM-SBRT plans were calculated on each CT in a manner that resulted in equal radiation fluence. The maximum and mean doses for OAR, and minimum, maximum, and mean doses for targets were compared. Data were collected from 40 dogs per anatomic site (head and neck, pelvis, and limbs). The average dose difference between minimum, maximum, and mean doses as calculated on pre- and ceCT plans for the gross tumor volume was less than 1% for all anatomic sites. Similarly, the differences between mean and maximum doses for OAR were less than 1%. The difference in dose distribution between plans made on CTs with and without contrast enhancement was tolerable at all treatment sites. Therefore, although caution would be recommended when planning IM-SBRT for tumors near "reservoirs" for contrast media (such as the heart and urinary bladder), findings supported the use of ceCT with this dose calculation algorithm for both target delineation and IM-SBRT treatment planning.

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“…A similar workflow as presented above has previously been described in the literature in combination with TomoTherapy (Accuray Corp., Sunnyvale, CA) and StatRT, commercial software specifically developed for TomoTherapy (10) . Additional research for a similar procedure on TomoTherapy exists for the treatment of spine metastases (19–22) . Although StatRT offers advanced capabilities for urgent treatments, it is limited to TomoTherapy.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of MV CBCT‐based treatment planning for urgent radiation therapy: dosimetric accuracy of MV CBCT‐based dose calculations

Held

Sneed

Fogh

et al. 2015

J Applied Clin Med Phys

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Unlike scheduled radiotherapy treatments, treatment planning time and resources are limited for emergency treatments. Consequently, plans are often simple 2D image‐based treatments that lag behind technical capabilities available for nonurgent radiotherapy. We have developed a novel integrated urgent workflow that uses onboard MV CBCT imaging for patient simulation to improve planning accuracy and reduce the total time for urgent treatments. This study evaluates both MV CBCT dose planning accuracy and novel urgent workflow feasibility for a variety of anatomic sites. We sought to limit local mean dose differences to less than 5% compared to conventional CT simulation. To improve dose calculation accuracy, we created separate Hounsfield unit–to–density calibration curves for regular and extended field‐of‐view (FOV) MV CBCTs. We evaluated dose calculation accuracy on phantoms and four clinical anatomical sites (brain, thorax/spine, pelvis, and extremities). Plans were created for each case and dose was calculated on both the CT and MV CBCT. All steps (simulation, planning, setup verification, QA, and dose delivery) were performed in one 30 min session using phantoms. The monitor units (MU) for each plan were compared and dose distribution agreement was evaluated using mean dose difference over the entire volume and gamma index on the central 2D axial plane. All whole‐brain dose distributions gave gamma passing rates higher than 95% for 2%/2 mm criteria, and pelvic sites ranged between 90% and 98% for 3%/3 mm criteria. However, thoracic spine treatments produced gamma passing rates as low as 47% for 3%/3 mm criteria. Our novel MV CBCT‐based dose planning and delivery approach was feasible and time‐efficient for the majority of cases. Limited MV CBCT FOV precluded workflow use for pelvic sites of larger patients and resulted in image clearance issues when tumor position was far off midline. The agreement of calculated MU on CT and MV CBCT was acceptable for all treatment sites.PACS numbers: 87.55.D‐, 87.57.Q‐

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A planning study for palliative spine treatment using StatRT and megavoltage CT simulation

Cited by 8 publications

References 30 publications

The dosimetric impact of stabilizing spinal implants in radiotherapy treatment planning with protons and photons: standard titanium alloy vs. radiolucent carbon‐fiber‐reinforced PEEK systems

The dosimetric impact of stabilizing spinal implants in radiotherapy treatment planning with protons and photons: standard titanium alloy vs. radiolucent carbon‐fiber‐reinforced PEEK systems

Dosimetric Consequences of Using Contrast‐enhanced Computed Tomographic Images for Intensity‐modulated Stereotactic Body Radiotherapy Planning

Feasibility of MV CBCT‐based treatment planning for urgent radiation therapy: dosimetric accuracy of MV CBCT‐based dose calculations

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