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1.
Phys Med Biol ; 68(19)2023 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-37652043

RESUMO

Objective. This study aimed to investigate the dosimetric impact of using population-based relative electron density (RED) overrides in lieu of simulation computerized tomography (CT) in a magnetic resonance linear accelerator (MRL) workflow for male pelvis patients. Additionally, the feasibility of using prostate specific membrane antigen positron emission tomography/CT (PSMA-PET/CT) scans to assess patients' eligibility for this proposed workflow was examined.Approach. In this study, 74 male pelvis patients treated on an Elekta Unity 1.5 T MRL were retrospectively selected. The patients' individual RED values for 8 organs of interest were extracted from their simulation-CT images to establish population-based RED values. These values were used to generate individual (IndD) and population-based (PopD) RED dose plans, representing current and proposed MRL workflows, respectively. Lastly, this study compared RED values obtained from CT and PET-CT scanners in a phantom and a subset of patients.Results. Population-based RED values were mostly within two standard deviations of ICRU Report 46 values. PopD plans were comparable to IndD plans, with the average %difference magnitudes of 0.5%, 0.6%, and 0.6% for mean dose (all organs), D0.1cm3(non-target organs) and D95%/D98% (target organs), respectively. Both phantom and patient PET-CT derived RED values had high agreement with corresponding CT-derived values, with correlation coefficients ≥ 0.9.Significance. Population-based RED values were considered suitable in a simulation-free MRL treatment workflow. Utilizing these RED values resulted in similar dosimetric uncertainties as per the current workflow. Initial findings also suggested that PET-CT scans may be used to assess prospective patients' eligibility for the proposed workflow. Future investigations will evaluate the clinical feasibility of implementing this workflow for prospective patients in the clinical setting. This is aimed to reduce patient burden during radiotherapy and increase department efficiencies.


Assuntos
Elétrons , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Humanos , Masculino , Estudos Prospectivos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
2.
J Med Radiat Sci ; 70(4): 491-497, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37540059

RESUMO

The magnetic resonance linear accelerator (MR-Linac) offers a new treatment paradigm, providing improved visualisation of targets and organs at risk while allowing for daily adaptation of treatment plans in real time. Online MR-guided adaptive treatment has reduced treatment uncertainties; however, the additional treatment time and resource requirements may be a concern. We present our experience of integrating an MR-Linac into a busy department and provide recommendations for improved clinical and resource efficiency. Furthermore, we discuss potential future technological innovations that can further optimise clinical productivity in a busy department.


Assuntos
Imageamento por Ressonância Magnética , Aceleradores de Partículas , Planejamento da Radioterapia Assistida por Computador
3.
J Med Radiat Sci ; 70(2): 199-205, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36890690

RESUMO

We present the first case in the literature of a 78-year-old woman with recurrent cardiac sarcoma adjacent to a bioprosthetic mitral valve treated with magnetic resonance linear accelerator (MR-Linac) guided adaptive stereotactic ablative body radiotherapy (SABR). The patient was treated using a 1.5 T Unity MR-Linac system (Elekta AB, Stockholm, Sweden). The mean gross tumour volume (GTV) size was 17.9 cm3 (range 16.6-18.9 cm3 ) based on daily contours and the mean dose received by the GTV was 41.4 Gy (range 40.9-41.6 Gy) in five fractions. All fractions were completed as planned and the patient tolerated the treatment well with no acute toxicity reported. Follow-up appointments at 2 and 5 months after the last treatment showed stable disease and good symptomatic relief. Results of transthoracic echocardiogram after radiotherapy showed that the mitral valve prosthesis was normally seated with regular functionality. This study provides evidence that MR-Linac guided adaptive SABR is a safe and viable option for the treatment of recurrent cardiac sarcoma with mitral valve bioprosthesis.


Assuntos
Bioprótese , Radiocirurgia , Sarcoma , Feminino , Humanos , Idoso , Valva Mitral/cirurgia , Planejamento da Radioterapia Assistida por Computador/métodos , Sarcoma/diagnóstico por imagem , Sarcoma/radioterapia , Sarcoma/cirurgia
4.
J Med Radiat Sci ; 70 Suppl 2: 99-106, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36502538

RESUMO

The introduction of magnetic resonance (MR) linear accelerators (MR-Linacs) into radiotherapy departments has increased in recent years owing to its unique advantages including the ability to deliver online adaptive radiotherapy. However, most radiation oncology professionals are not accustomed to working with MR technology. The integration of an MR-Linac into routine practice requires many considerations including MR safety, MR image acquisition and optimisation, image interpretation and adaptive radiotherapy strategies. This article provides an overview of training and credentialing requirements for radiation oncology professionals to develop competency and efficiency in delivering treatment safely on an MR-Linac.


Assuntos
Radio-Oncologistas , Radioterapia Guiada por Imagem , Humanos , Imageamento por Ressonância Magnética/métodos , Aceleradores de Partículas , Radioterapia Guiada por Imagem/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Espectroscopia de Ressonância Magnética , Credenciamento
5.
J Med Radiat Sci ; 70 Suppl 2: 94-98, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36572532

RESUMO

The introduction of magnetic resonance (MR) linear accelerators (MR-Linac) marks the beginning of a new era in radiotherapy. MR-Linac systems are currently being operated by teams of radiation therapists (RTs), radiation oncology medical physicists (ROMPs) and radiation oncologists (ROs) due to the diverse and complex tasks required to deliver treatment. This is resource-intensive and logistically challenging. RT-led service delivery at the treatment console is paramount to simplify the process and make the best use of this technology for suitable patients with commonly treated anatomical sites. This article will discuss the experiences of our department in developing and implementing an RT-led workflow on the 1.5 T MR-Linac.


Assuntos
Radioterapia (Especialidade) , Radioterapia Guiada por Imagem , Humanos , Imageamento por Ressonância Magnética , Planejamento da Radioterapia Assistida por Computador , Espectroscopia de Ressonância Magnética
6.
J Med Imaging Radiat Oncol ; 66(1): 138-145, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34643065

RESUMO

INTRODUCTION: The magnetic resonance linear accelerator (MRL) offers improved soft tissue visualization to guide daily adaptive radiotherapy treatment. This manuscript aims to report initial experience using a 1.5 T MRL in the first 6 months of operation, including training, workflows, timings and dosimetric accuracy. METHODS: All staff received training in MRI safety and MRL workflows. Initial sites chosen for treatment were stereotactic and hypofractionated prostate, thoraco-abdomino-pelvic metastasis, prostate bed and bladder. The Adapt To Shape (ATS) workflow was chosen to be the focus of treatment as it is the most robust solution for daily adaptive radiotherapy. A workflow was created addressing patient suitability, simulation, planning, treatment and peer review. Treatment times were recorded breaking down into the various stages of treatment. RESULTS: A total of 37 patients were treated and 317 fractions delivered (of which 313 were delivered using an ATS workflow) in our initial 6 months. Average treatment times over the entire period were 50 and 38 min for stereotactic and non-stereotactic treatments respectively. Average treatment times reduced each month. The average difference between reference planned and ionization chamber measured dose was 0.0 ± 1.4%. CONCLUSION: The MRL was successfully established in an Australian setting. A focus on training and creating a detailed workflow from patient selection, review and treatment are paramount to establishing new treatment programmes.


Assuntos
Planejamento da Radioterapia Assistida por Computador , Radioterapia Guiada por Imagem , Austrália , Humanos , Imageamento por Ressonância Magnética , Masculino , Aceleradores de Partículas , Dosagem Radioterapêutica , Fluxo de Trabalho
7.
Clin Transl Radiat Oncol ; 31: 64-70, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34646950

RESUMO

BACKGROUND: Analysis of Data to Advance Personalised Therapy with MR-Linac (ADAPT-MRL) is a multi-site, multinational, observational cohort registry designed to collect data on the use of the magnetic resonance linear accelerator (MR-Linac) for radiation therapy and patient outcomes. The registry will provide a linked repository of technical and clinical data that will form a platform for prospective studies and technology assessment. METHODS: Design: This registry aims to include an estimated 10,000 eligible participants across Australia and other countries over a 7- to 10-year period. Participants will undergo treatment and assessments in accordance with standard practice. Toxicity and survival outcomes will be assessed at baseline, during treatment, and with 3 monthly follow-up until 24 months, patient reported outcome measures will also be collected. Participants with a variety of cancers will be included. DISCUSSION: Data obtained from the ADAPT-MRL registry is expected to provide evidence on the safety and efficacy of the MR-Linac, a new technical innovation in radiation oncology. We expect this registry will generate data that will be used to optimise treatment techniques, MR-Linac software algorithms, evaluate participants' outcomes and toxicities and to create a repository of adapted plans, anatomical and functional MR sequences linked to participants' outcomes.

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