2 research outputs found
Dosimetric phantom consistency of TMR-10 protocol in homogeneous and inhomogeneous regions in gamma knife radiosurgery planning
Introduction: The algorithms used in the GammaPlan treatment planning system are “Tissue Maximum Ratio (TMR) classical,”“TMR 10,” and “convolution” algorithms, respectively. In this study, the consistency of dosimetric measurements with the TMR 10 protocol used in SRC (stereotactic radiosurgery) planning in lesions located in homogeneous and inhomogeneous regions in different intracranial location scenarios was investigated. Methods: In this study, the accuracy of administration of multiple metastasis treatment on the Gamma Knife Perfexion device was investigated. Computed tomography was performed with 1 mm cross-section intervals of CIRS brand Atom randofantoma. Critical organs and three different brain metastases located in homogeneous and heterogeneous regions, which are not on the same plane with each other, were drawn on the phantom. Planned target volume (PTV) volumes were created without margining the drawn gross tumor volumes, and three separate plans were made for three different PTV volumes. All plans were calculated using the TMR 10 algorithm. Critical organ doses were kept below the brain-SRC criteria for all calculated plans. Gafchromic EBT-3 film was placed on the sections with the target volume drawn on the phantoms and irradiated (1600 cGy, 50% isodose area). Measurements were made three times. The measured film results and the doses calculated from the planning were compared with gamma index analysis for different tolerance values. Results: In our study, for three different lesions planned and irradiated with different gradient index values, a difference of 2.11–9.58% was observed between the values calculated with the TMR-10 protocol and the values obtained in the dosimet- ric measurement. A decrease in consistency was observed, especially in inhomogeneous region placements. Discussion and Conclusion: There may be inconsistency between the TMR-10 protocol and actual dosimetric measurements, especially around inhomogeneous intracranial structures. We hope that this inconsistency will decrease in the future with the developing dose calculation protocols
Paradigm shift in vertebral eosinophilic granuloma
Objective: Eosinophilic granuloma is the most common type of Langerhans cell histiocytosis. Vertebral bone involvement of eosinophilic granuloma is a rare disease. There are few studies in the literature on patients with vertebral bone involvement diagnosed with eosinophilic granuloma. There is still no clear protocol for the treatment of patients with vertebral involvement with eosinophilic granuloma. This article is a summary of the clinical follow-ups of our 6 cases diagnosed with spinal eosinophilic granuloma. We changed the chemotherapy protocol or extended the duration of chemotherapy in patients with progressive disease.Methods: In this study, there are six patients (4 male and 2 female) with vertebral involvement of eosinophilic granuloma in our hospital between September 2017 and August 2022. The clinical findings, radiological images, treatments and follow-up results of the patients were analyzed retrospectively.Results: In the follow-ups, a new vertebral bone involvement was observed in two patients and a femoral bone involvement was observed in another patient. One patient with neurological deficit underwent surgical treatment. Chemotherapy treatment was given to four patients with multiple bone involvement or recurrence. No recurrence was observed in three patients who started chemotherapy treatment after recurrence.Conclusions: Surgical treatment should be considered in patients with neurological deficits and spinal instability. According to the results of our study, patients with multiple bone or systemic involvement and no neurological deficit should receive chemotherapy treatment. We recommend changing the chemotherapy protocol or extending the chemotherapy duration in patients with progressive disease