Purpose. To compare the sensitivity of MRS metabolites and MoCA and ACE‐R cognitive tests in the detection of radiation‐induced injury in low grade glioma (LGG) patients in early and early delayed postradiation stages. Methods. MRS metabolite ratios of NAA/Cr and Cho/Cr, ACE‐R and MoCA cognitive tests, and dosimetric parameters in corpus callosum were analyzed during RT and up to 6‐month post‐RT for ten LGG patients. Results. Compared to pre RT baseline, a significant decline in both NAA/Cr and Cho/Cr in the corpus callosum was seen at the 4th week of RT, 1, 3, and 6‐month post‐RT. These declines were detected at least 3 months before the detection of declines in cognitive functions by ACE‐R and MoCA tools. Moreover, NAA/Cr alterations at 4th week of RT and 1‐month post‐RT were significantly negatively correlated with the mean dose received by the corpus callosum, as well as the corpus callosum 40 Gy dose volume, i.e., the volume of the corpus callosum receiving a dose greater than 40 Gy. Conclusion. MRS‐based biomarkers may be more sensitive than the state‐of‐the‐art cognitive tests in the prediction of postradiation cognitive impairments. They would be utilized in treatment planning and dose sparing protocols, with a specific focus on the corpus callosum in the radiation therapy of LGG patients.

Background. Chemotherapy-induced cytopenia is the most frequent side effect of chemoradiotherapy in glioblastoma patients which may lead to reduced delivery of treatment. This study aims to develop a predictive model that is able to forecast the cytopenia induced by temozolomide (TMZ) during concomitant chemoradiotherapy. Methods. Medical records of 128 patients with newly diagnosed glioblastoma were evaluated to extract the baseline complete blood test before and during the six weeks of chemoradiotherapy to create a dataset for the development of ML models. Using the constructed dataset, different ML algorithms were trained and tested. Results. Our proposed algorithm achieved accuracies of 85.6, 88.7, and 89.3 in predicting thrombocytopenia, lymphopenia, and neutropenia, respectively. Conclusions. The algorithm designed and developed in this study, called PrACTiC, showed promising results in the accurate prediction of thrombocytopenia, neutropenia, and lymphopenia induced by TMZ in glioblastoma patients. PrACTiC can provide valuable insight for physicians and help them to make the necessary treatment modifications and prevent the toxicities.

Background: Cone beam computed tomography (CBCT) has been broadly acceptable in recent years as a radiography modality for diagnosis, treatment planning and follow up in dentistry. Some important parameters such as radiation dose, image quality and field of view are considered as a criteria for deciding whether or not a CBCT dental unit is suitable for a particular application. Objectives: This study aims to evaluate the effect of exposure levels on the absorbed dose of mandible and salivary glands according to various settings of milliamperage (mA) in CBCT. Materials and Methods: A very advanced multilayers head and neck phantom was constructed for this study. This phantom was built based on the CT images of a specific patient with an average size. This phantom was constructed using proper substitutes for soft tissue and bone according to their physical properties. Therefore, there was a high level of agreement with the patient's body. This phantom enables us to measure the absorbed dose inside the organs. Dosimetry has been performed by Soredex Cranex3d CBCT. For film dosimetry, AGFA films were used in various layers of the phantom. The mAs of the device was changed in the range of 2, 4, 6, 8, 10 and 12 mA. Results: The maximum and the minimum absorbed dose was placed in the area related to the right mandible and the left submandibular gland. The increase of absorbed dose by mA increase was meaningful in the confidence level of 95% for all scanned areas. By changing mA from 2 to 12, the absorbed dose varied significantly with a maximum 5.44-fold variation between the highest and lowest dose for the parotid gland. Conclusion: This study has shown that there is a meaningful relationship between the increase of mA and increase of absorbed dose in different parts of the dentomaxillofacial area, including the mandible, submandibular and parotid glands. It is concluded that as long as the image quality is acceptable for diagnostic purposes, the mAs of the CBCT should be kept in a low range to minimize the absorbed dose. Keywords: Absorbed Dose; CBCT; Radiation Setting; Head Phantom