Towards a One-Step Scan and Treat Process for Palliative Radiotherapy - a Potential Application for Cone Beam Computerized Tomography (CBCT (original) (raw)
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International Journal of Radiation Oncology*Biology*Physics, 2012
Palliative radiotherapy should be delivered as soon as is reasonable. The goal of our project was to convert a multistep, multisystem radiotherapy planning-totreatment process into a onestep integrated process using a cone-beam computed tomographyeenabled treatment unit. Our study showed that the process can be executed with a mean duration of 35 minutes while preserving the quality of the treatment plan and is Purpose: To develop a cone-beam computed tomography (CT)eenabled one-step simulation-totreatment process for the treatment of bone metastases. Methods and Materials: A three-phase prospective study was conducted. Patients requiring palliative radiotherapy to the spine, mediastinum, or abdomen/pelvis suitable for treatment with simple beam geometry (2 beams) were accrued. Phase A established the accuracy of cone-beam CT images for the purpose of gross tumor target volume (GTV) definition. Phase B evaluated the feasibility of implementing the cone-beam CTeenabled planning process at the treatment unit. Phase C evaluated the online cone-beam CTeenabled process for the planning and treatment of patients requiring radiotherapy for bone metastases. Results: Eighty-four patients participated in this study. Phase A (n Z 9) established the adequacy of cone-beam CT images for target definition. Phase B (n Z 45) established the quality of treatment plans to be adequate for clinical implementation for bone metastases. When the process was applied clinically in bone metastases (Phase C), the degree of overlap between planning computed tomography (PCT) and cone-beam CT for GTV and between PCT and cone-beam CT for treatment field was 82% AE 11% and 97% AE 4%, respectively. The oncologist's decision to accept the plan under a time-pressured environment remained of high quality, with the conebeam CTegenerated treatment plan delivering at least 90% of the prescribed dose to 100% AE 0% of the cone-beam CT planning target volume (PTV). With the assumption that the PCT PTV is the gold-standard target, the cone-beam CTegenerated treatment plan delivered at least 90% and at
International Journal of Radiation Oncology*Biology*Physics, 2007
Purpose: To assess the feasibility of an online strategy for palliative radiotherapy (RT) of spinal bone metastasis, which integrates imaging, planning, and treatment delivery in a single step at the treatment unit. The technical challenges of this approach include cone-beam CT (CBCT) image quality for target definition, online planning, and efficient process integration. Methods and Materials: An integrated imaging, planning, and delivery system was constructed and tested with phantoms. The magnitude of CBCT image artifacts following the use of an antiscatter grid and a nonlinear scatter correction was quantified using phantom data and images of patients receiving conventional palliative RT of the spine. The efficacy of online planning was then assessed using corrected CBCT images. Testing of the complete process was performed on phantoms with assessment of timing and dosimetric accuracy. Results: The use of image corrections reduced the cupping artifact from 30% to 4.5% on CBCT images of a body phantom and improved the accuracy of CBCT numbers (water: ؎ 20 Hounsfield unit [HU], and lung and bone: to within ؎ 130 HU). Bony anatomy was clearly visible and was deemed sufficient for target definition. The mean total time (n ؍ 5) for application of the online approach was 23.1 min. Image-guided dose placement was assessed using radiochromic film measurements with good agreement (within 5% of dose difference and 2 mm of distance to agreement). Conclusions: The technical feasibility of CBCT-guided online planning and delivery for palliative single treatment has been demonstrated. The process was performed in one session equivalent to an initial treatment slot (<30 min) with dosimetric accuracy satisfying accepted RT standards.
Cone-beam-CT guided radiation therapy: technical implementation
Radiotherapy and Oncology, 2005
Background and purpose: X-ray volumetric imaging system (XVI) mounted on a linear accelerator is available for image guidance applications. In preparation for clinical implementation, phantom and patient imaging studies were conducted to determine the irradiation parameters that would trade-off image quality, patient dose and scanning time.
Cumhuriyet Medical Journal
The aim of the present study was to determine the methods to reduce the radiation dose during imaging carried out for patients with bone or other organ metastases who were treated with palliative radiotherapy. In planning stages of treatment for these patients, tomographic imaging with computed tomography (CT) is performed on affected area using three-dimensional (3D) conformal radiotherapy. To what level the radiation dose could be lowered in imaging was investigated via changing the parameters used in CT scanning. Method: Twenty seven patients with metastases treated in the Radiation Oncology department (16M, 11F, mean age 65.2 ± 11.9 years) were included in the study. These patients underwent a total of 30 palliative radiotherapy treatments. Standard CT dose of 72 milli-ampere-second (mAs) and 130 peak kilo voltage (kVp) in CT 1 scanning carried out for radiotherapy planning was lowered to 30mAs and 130kVp in CT 2 scanning. Results: Radiation dose was reduced by 62.68% ± 0.02 percent as a result of changes made in planning CT scan (p<0.0001). Analysis of the images obtained revealed that despite the minimal reduction in image quality, results had no effect on treatment planning. Conclusions: It was concluded that the radiation dose could be reduced via making changes in the parameters of CT scanning during palliative radiotherapy planning stage.
Improving the Palliative Patient Journey in Radiation Oncology
International Journal of Radiation Oncology*Biology*Physics, 2019
Purpose/Objective(s): Radiotherapy (RT) has an important role in the symptomatic relief and improvement in the quality of life for patients with bony and soft tissue metastases. We hypothesised a streamlined palliative care pathway by removing the need for a simulation computed tomography (sCT) scan. The aim of this study was to investigate the use of the patient's diagnostic CT (dCT) dataset to produce palliative 3D conformal radiotherapy (3D-CRT) treatment plans. Materials/Methods: The impact on dose distribution of Hounsfield Units (HUs) variance from different dCT sources, patient position and couch curvature was assessed retrospectively. From 150 patients treated with palliative 3D-CRT, a sample of 92 diagnostic datasets covering the most common treatment sites were used. A slab geometry phantom was created in the treatment planning system to compare the dosimetric impact of variance in HU. Dosimetric evaluations were undertaken by comparing the clinical plan calculated with fixed monitor units on the dCT. The integration of dCT treatment planning into the palliative care path was done prospectively. Patients booked for palliative RT (1 to 5 fractions), and a dCT acquired within the last 4 weeks, were included. The dCT had to encompass the area of interest and have a complete field of view including body contours. Patients were then simulated as per standard department protocol, but in the dCT position. Treatment was dual planned on the dCT and the sCT and delivered with daily image guidance as per routine treatment. Results: The mean HU for vertebra (nZ12), femoral head (nZ17), lung (nZ22) and soft tissue (nZ41), was 185AE50, 416AE125,-741AE91, and 59AE41 respectively. From tissue slab phantoms, dose differences due to HU variation resulted in lung HU changes that impact dosimetry in the order of 3-5% for 6MV. In patient dCTs, uncertainty in dose calculation due to HU variation in the lung was in the order of 2.5-5% for 10MV and 1.5-3.5% for 18MV which needs to be considered when calculating on diagnostic scans since the higher the energy, the less impact change in HU has on dose. From the retrospective analysis, the most suitable treatment sites for the application of dCT planning were the abdomen, lumbar or thoracic spine, pelvis and sacrum. Of the first 35 patients planned and treated with dCT, 28 plans used 18MV, 6 plans 6MV and one plan 6/18MV mix. A curved full body vac-bag was designed to enable better replication of the posterior body curvature in dCTs for treatment. Dosimetric evaluations were made between the dCT and pre-treatment cone beam CT in 32 patients, with the planning target volume (PTV) dose difference being <2% in 29 patients. Conclusion: 3D-CRT plans for patients with bony and soft tissue metastases can be produced using dCT, eliminating the need for the sCT. This was demonstrated to be feasible and has been implemented as a standard clinical care pathway, with major implications for improving the care journey for patients with metastatic cancer.
Rapid palliative radiotherapy unit: multidisciplinary management of bone metastases
La radiologia medica, 2012
Purpose. The aim of this study was to highlight the advantages of rapid access to a palliative radiotherapy unit adopting a multidisciplinary approach to symptom management to relieve pain and improve quality of life in patients with bone metastases. Materials and methods. From January 2007 to December 2008, 142 oncological patients were treated with linear accelerator radiotherapy (RT) administered in a single 8-Gy fraction. The European Organization for Research and Treatment Quality of Life Questionnaire (EORTC QLQ-C30) was administered to each patient at admission and at subsequent intervals. A traditional simulator was used to define the correct patient setup, and all treatment plans were performed with a two-dimensional technique.. Results. Ninety-six patients agreed to fill in the EORTC QLQ-C30 questionnaire; 80 actually completed it. Twelve weeks after RT, a reduction in pain level compared with baseline (T0) was recorded, which was classified as 1 in 36 patients (45%) and 2 in 44 patients (55%). Pain interference with daily activities was also recorded, with significantly reduced scores with respect to T0: 1 in eight patients (10%), 2 in 28 patients (35%) and 3 in 44 patients (55%); quality of life scores also improved with respect to T0: 2 in 28 patients (35%), 3 in 23 patients (29%), 4 in 22 patients (27%) and 5 in seven patients (9%). Conclusions. The proposal for treating patients with painful bone metastases with a single 8-Gy fraction of RT, with all the procedures being performed on the same day, offers many advantages in terms of pain relief, quality of life and clinical management. Riassunto Obiettivo. La finalità di questo studio è stata quella di mettere in evidenza i vantaggi di un accesso rapido all'unità di radioterapia palliativa, adottando un approccio multidisciplinare alla gestione del sintomo, con la finalità di ridurre il dolore e migliorare la qualità di vita dei pazienti con metastasi ossee. Materiali e metodi. Da gennaio 2007 a dicembre 2008, 142 pazienti oncologici sono stati trattati con radioterapia in singola frazione di 8 Gy. Ad ogni paziente è stato distribuito l'European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ)-C30 all'inizio del trattamento e ad intervalli successivi. Per definire il corretto posizionamento del paziente è stato utilizzato un simulatore tradizionale; tutti i piani di cura sono stati realizzati con tecnica 2D. La radioterapia con acceleratore lineare è stata effettuata somministrando la dose di 8 Gy in frazione singola. Risultati. Novantasei pazienti hanno accettato di compilare il questionario EORTC QLQ-C30, ma effettivamente 80 lo hanno completato. A 12 settimane dalla radioterapia si è registrata una riduzione dell'intensità del dolore rispetto al T0, che è stato classificato come 1 e 2 da 36 (45%) e 44 pazienti (55%), rispettivamente. Rispetto al T0, si è registrata anche una riduzione dell'interferenza del dolore con le attività quotidiane, che è stata classificata come 1, 2 e 3 da 8 (10%), 28 (35%) e 44 (55%) pazienti, rispettivamente. Rispetto al T0 c'è stato un miglioramento della qualità di vita, classificata come 2, 3, 4 e 5 da 28 (35%), 23 (29%), 22 (27%) e 7 pazienti (8%), rispettivamente.
Inclusion of the dose from kilovoltage cone beam CT in the radiation therapy treatment plans
Medical Physics, 2009
Cone beam CT is increasingly being used for daily patient positioning verification during radiation therapy treatments. The daily use of CBCT could lead to accumulated patient doses higher than the older technique of weekly portal imaging. There have been several studies focusing on measurement or calculation of the patient dose from CBCT recently. Methods: This study investigates the feasibility of configuring a kV x-ray source in a commercial treatment planning system to calculate the dose to patient resulting from an IGRT procedure. The method proposed in this article can be used to calculate dose from CBCT imaging procedure and include that in the patient treatment plans. Results: The kilovoltage beam generated by the CBCT imager has been modeled using the planning system. The modeled profiles agree with the measured ones to within 5%. The modeled beam was used to calculate dose to phantom in the pelvic region and the calculations were compared to TLD measurements. The agreement between calculated and measured doses ranges from 0% to 19% in soft tissue with larger variations observed near and within the bone. Conclusions: The modeling of the beam produces reasonable results and the dose calculation comparisons indicate the potential for computing kilovoltage CBCT doses using a treatment planning system. Further improvements in the dose calculation algorithm are necessary, especially for dose calculations in and near the bone.
Adaptive radiotherapy based on contrast enhanced cone beam CT imaging
Acta Oncologica, 2010
Cone beam CT (CBCT) imaging has become an integral part of radiation therapy, with images typically used for offl ine or online patient setup corrections based on bony anatomy co-registration. Ideally, the co-registration should be based on tumor localization. However, soft tissue contrast in CBCT images may be limited. In the present work, contrast enhanced CBCT (CECBCT) images were used for tumor visualization and treatment adaptation. Material and methods. A spontaneous canine maxillary tumor was subjected to repeated cone beam CT imaging during fractionated radiotherapy (10 fractions in total). At fi ve of the treatment fractions, CECBCT images, employing an iodinated contrast agent, were acquired, as well as pre-contrast CBCT images. The tumor was clearly visible in post-contrast minus pre-contrast subtraction images, and these contrast images were used to delineate gross tumor volumes. IMRT dose plans were subsequently generated. Four different strategies were explored: 1) fully adapted planning based on each CECBCT image series, 2) planning based on images acquired at the fi rst treatment fraction and patient repositioning following bony anatomy co-registration, 3) as for 2), but with patient repositioning based on co-registering contrast images, and 4) a strategy with no patient repositioning or treatment adaptation. The equivalent uniform dose (EUD) and tumor control probability (TCP) calculations to estimate treatment outcome for each strategy . Results . Similar translation vectors were found when bony anatomy and contrast enhancement co-registration were compared. Strategy 1 gave EUDs closest to the prescription dose and the highest TCP. Strategies 2 and 3 gave EUDs and TCPs close to that of strategy 1, with strategy 3 being slightly better than strategy 2. Even greater benefi ts from strategies 1 and 3 are expected with increasing tumor movement or deformation during treatment. The non-adaptive strategy 4 was clearly inferior to all three adaptive strategies. Conclusion . CECBCT may prove useful for adaptive radiotherapy. Acta Oncologica, 2010; 49: 972-977
Cancer Investigation, 2014
Purpose: To evaluate the feasibility and response to palliative radiotherapy delivered with static ports of tomotherapy-TomoDirect (TD) in patients affected with painful bone metastases from solid tumors. Methods: A prospective cohort of 130 patients (185 osseous lesions) was treated between 2010 and 2013 with TD. Three fractionation schedules were employed according to clinical decision-making (3 Gy × 10; 4 Gy × 5; 8 Gy × 1). Pain response was investigated at 2 weeks and 2 months (for evaluable patients). The Numeric Rating Scale (NRS-11) was used to assess pain. Response rates to radiotherapy were calculated following the criteria of the International Bone Metastases Consensus Group (IBMCG), accounting for the use of concomitant analgesics (response: complete or partial; non-response: stable pain, pain progression or "other"). Analgesic consumption was recalculated into the daily oral morphine-equivalent dose (OMED). Results: Most of the patients had 1-2 bone metastases (91); those with multiple lesions mostly had a metachronous presentation (60%). Synchronous lesions were mainly approached with multiple plans (63%). Most treatments employed 3-4 fields (77%). Treatment times ranged from 255 to 939 s depending on fractionation, fields, and target lesions number. At 2 weeks, the median self-reported worst pain decreased significantly as median oral morphine-equivalent dose regardless of fractionation used. The response rate according to the IBMCG-based response categories ranged from 45 to 55%. Pain relief duration seems (response at 2 months) slightly inferior with the single fraction approach, with a higher re-treatment rate. At 2 weeks, the median self-reported worst pain and OMED significantly decreased regardless of fractionation (response rate: 49-55%). Pain relief decreased at 2 months, especially for single fraction (higher re-treatment rate).
Radiotherapy and Oncology, 2002
Purpose: To reach a consensus on a set of optimal endpoint measurements for future external beam radiotherapy trials in bone metastases. Methods: An International Bone Metastases Consensus Working Party invited principal investigators and individuals with a recognized interest in bone metastases to participate in the two surveys and a panel meeting on their preference of choice of optimal endpoints. Results: Consensus has been reached on the following: (a) eligibility criteria for future trials; (b) pain and analgesic assessments; (c) radiation techniques; (d) follow-up and timing of assessments; (e) parameters at follow-up; (f) endpoints; (g) re-irradiation; and (h) statistical analysis. Conclusions: Based on the available literature and the clinical experience of the working party members, an acceptable set of endpoints has been agreed upon for future clinical trials to promote consistency in reporting. It is intended that the consensus will be reexamined every 5 years. Areas of further research were identified.