Radiotherapy in oncological emergencies: fast-track treatment planning

Abstract

Background and purpose To report on our clinical experience with a newly implemented workflow for radiotherapy (RT) emergency treatments, which allows for a fast treatment application outside the regular working-hours, and its clinical applicability. Methods Treatment planning of 18 emergency RT patients was carried out using diagnostic computed tomography (CT) without a dedicated RT simulation CT. The cone-beam CT (CBCT) deviations of the first RT treatment were analyzed regarding setup accuracy. Furthermore, feasibility of the “fast-track” workflow was evaluated with respect to dose deviations caused by different Hounsfield unit (HU) to relative electron density (rED) calibrations and RT treatment couch surface shapes via 3D gamma index analysis of exemplary treatment plans. The dosimetric uncertainty introduced by different CT calibrations was quantified. Results Mean patient setup vs. CBCT isocenter deviations were (0.49 ± 0.44) cm (x), (2.68 ± 1.63) cm (y) and (1.80 ± 1.06) cm (z) for lateral, longitudinal and vertical directions, respectively. Three out of four dose comparisons between the emergency RT plan calculated on the diagnostic CT and the same plan calculated on the treatment planning CT showed clinically acceptable gamma passing rates, when correcting for surface artifacts. The maximum difference of rED was 0.054, while most parts of the CT calibration curves coincided well. Conclusion In an emergency RT setting, the use of diagnostic CT data for treatment planning might be time-saving and was shown to be suitable for many cases, considering reproducibility of patient setup, accuracy of initial patient setup and accuracy of dose-calculation.

Evaluation of a workflow for cone‐beam CT‐guided online adaptive palliative radiotherapy planned using diagnostic CT scans

“…In contrast to the previous work, our study did not encounter issues arising from differences between the curved dCT couch and the flat RT couch. 10 The observed differences in target coverage between the TP R and TP A were less than 0.2%, a finding comparable to previous studies using 3D conformal plans. 16 Although dose differences to the OARs varied up to 10% between the TP A and TP R , OAR doses generally met plan constraints for palliative treatment.…”

“…[6][7][8] A workflow using available diagnostic imaging for treatment planning has been clinically implemented for simple 3D conformal plans at some institutions. [9][10][11] However, any differences in patient positioning, body contour,and tumor size during RT-delivery could result in undesirable deviations when intensity-modulated plans (IMRT) are delivered. 10 IMRT plans are desirable as they can decrease doses to organs at risk (OARs).…”

“…[9][10][11] However, any differences in patient positioning, body contour,and tumor size during RT-delivery could result in undesirable deviations when intensity-modulated plans (IMRT) are delivered. 10 IMRT plans are desirable as they can decrease doses to organs at risk (OARs). [12][13][14] However, previous studies that used diagnostic CTs (dCT) for treatment planning in an urgent palliative RT setting advised caution in more complex cases.…”

“…[12][13][14] However, previous studies that used diagnostic CTs (dCT) for treatment planning in an urgent palliative RT setting advised caution in more complex cases. 9,10 Other authors have attempted to replicate positioning during treatment by using an vacuum-bag, 6D setup corrections, or applying rigid shifts and rotations to account for differences in positioning during treatment. 10,11,15,16 Overall, these studies suggested that dCT-based treatments are feasible, but that further investigation of the workflow is required in integrated treatment platforms.…”

Radiation oncology practice during COVID-19 pandemic in developing countries

“…In life-threatening situations such as those involving bleeding and spinal cord compression, in which RT needs to be delivered urgently, the use of a hypofractionated regimen is preferable to achieve a more rapid response; the use of these regimens also adheres to the protocols in place during the COVID-19 pandemic[ 14 ]. It may also be possible to omit computed tomography (CT) simulations and to use diagnostic CT as an alternative fast track to RT during emergencies[ 15 ], this will help to minimize exposure and short preparation time as shown in Figure 1 .…”