Comparison of phantom materials for use in quality assurance of microbeam radiation therapy
Microbeam radiation therapy (MRT) is a promising radiotherapy modality that uses arrays of spatially fractionated micrometre-sized beams of synchrotron radiation to irradiate tumours. Routine dosimetry quality assurance (QA) prior to treatment is necessary to identify any changes in beam condition from the treatment plan, and is undertaken using solid homogeneous phantoms. Solid phantoms are designed for, and routinely used in, megavoltage X-ray beam radiation therapy. These solid phantoms are not necessarily designed to be water-equivalent at low X-ray energies, and therefore may not be suitable for MRT QA. This work quantitatively determines the most appropriate solid phantom to use in dosimetric MRT QA. Simulated dose profiles of various phantom materials were compared with those calculated in water under the same conditions. The phantoms under consideration were RMI457 Solid Water (Gammex-RMI, Middleton, WI, USA), Plastic Water (CIRS, Norfolk, VA, USA), Plastic Water DT (CIRS, Norfolk, VA, USA), PAGAT (CIRS, Norfolk, VA, USA), RW3 Solid Phantom (PTW Freiburg, Freiburg, Germany), PMMA, Virtual Water (Med-Cal, Verona, WI, USA) and Perspex. RMI457 Solid Water and Virtual Water were found to be the best approximations for water in MRT dosimetry (within ± 3% deviation in peak and 6% in valley). RW3 and Plastic Water DT approximate the relative dose distribution in water (within ± 3% deviation in the peak and 5% in the valley). PAGAT, PMMA, Perspex and Plastic Wat...
Authors: Fukuda H, Takekuma M, Hirashima Y Abstract A 62-year-old Japanese woman developed numbness of the extremities and megaloblastic anemia. She had undergone total abdominal hysterectomy, whole-pelvis radiation therapy and chemotherapy for gynecological cancer 10 years before. Chronic abdominal pain, diarrhea and intermittent small-bowel obstruction had afflicted her for a long time. We diagnosed her with vitamin B12 deficiency anemia and polyneuropathy due to chronic radiation enteritis causing malabsorption. Vitamin B12 injections improved her numbness and anemia. The early diagnosis and treatment of deficie...
ConclusionsThe best management strategy of RIBP is prevention by reducing total RT doses and close follow-up. However, when RIBP occurs, we recommend treatment with HBO therapy, steroids, trental, and vitamin E as tolerable.
This article summarizes advancements in using FDG-PET for patients with locally advanced NSCLC treated with definitive radiation therapy (RT). This article discusses prognostication of outcome based on pretreatment or midtreatment PET metrics, using textural image features to predict treatment outcomes, and using PET to define RT target volumes and inform RT dose modifications. The role of PET is evolving and is moving toward using quantitative image information, with the overarching goal of individualizing therapy to improve outcomes for patients with NSCLC. PMID: 31735302 [PubMed - in process]
Radiation therapy needs to balance between delivering a high dose to targets and the lowest possible dose to the organs at risk. Dose-volume histograms (DVHs) summarize the distribution of radiation doses in the irradiated structures. The interpretation can however be a challenge when the number of structures is high. We propose the use of a simple summary metric. We define the mean absolute dose deviation (MADD) as the average of absolute differences between a DVH and a reference dose. The properties are evaluated through numerical analysis.
Conclusion: Bevacizumab is a effective and safe for treatment of RIBE after GKRS. A protocol-based dose schedule in addition to frequent clinical and radiological evaluations are required. Bevacizumab should be considered as an early treatment option for RIBE.
Tumor-associated myeloid cells (TAMCs) are key drivers of immunosuppression in the tumor microenvironment, which profoundly impedes the clinical response to immune-dependent and conventional therapeutic modalities. As a hallmark of glioblastoma (GBM), TAMCs are massively recruited to reach up to 50% of the brain tumor mass. Therefore, they have recently been...
We present a prospective study of hypofractionated, image-guided radiation therapy (HIGRT) to a single site of metastatic disease concurrently with atezolizumab in patients with metastatic NSCLC.
Conditions: Rectal Adenocarcinoma; Clinical Stage: Stage II (T3-4, N-); Stage III (Any T, N+) Interventions: Drug: TSR-042; Drug: capecitabine; Radiation: Intensity Modulated Radiation Therapy (IMRT) Sponsors: Memorial Sloan Kettering Cancer Center; Tesaro, Inc. Not yet recruiting
In Table 2 of the above-referenced article, the Desirable dose of Thyroid should have read “V50