Objective:To explore the feasibility of applying ArcherQA to independent dose verification of MR-guided online adaptive radiotherapy (ART) plans performed on Elekta Unity 1.5 Tesla (T) magnetic resonance-linear accelerator (MR-Linac).Methods:The dose calculation accuracy of ArcherQA under a specific magnetic field was validated using a homogeneous water phantom. A total of 32 patients who received MR-guided online ART on Elekta Unity were randomly selected by lottery, with 32 offline plans and 177 online plans for five treatment sites (brain, mediastinum, liver, kidney, and vertebral body) enrolled. Finally, the γ pass rates (threshold: 10%; criteria: 3 mm/3% and 2 mm/2%) were compared among the result upon independent dose verification of ArcherQA, measurements of ArcCheck, and calculations using the Monaco treatment planning system (TPS) to quantitatively evaluate the accuracy and efficiency of ArcherQA in independent dose verification of online plans on Elekta Unity.Results:ArcherQA was proven accurate in calculating the dose distribution of therapeutic photon beams under the specific magnetic field. With the 3 mm/3% criterion, the γ pass rates of verification result exceeded 99% in all square fields of a water phantom. Under the stricter 2 mm/2% criterion, the γ pass rates also surpassed 95% in all square fields except 20 cm × 20 cm field. Regarding the verification of treatment plans, the ArcherQA result were found to be highly consistent with those measured or calculated using ArcCheck and Monaco TPS, with the average γ pass rates exceeding 99% under the 3 mm/3% criterion and above 97% under the 2 mm/2% criterion. ArcherQA was acceptably efficient for independent dose verification of online plans, with 50 to 150 s, (108 s on average) required to complete the independent dose verification of 177 online plans.Conclusions:ArcherQA allows for accurately and efficiently calculating the dose distribution of therapeutic photon beams under a specific magnetic field, establishing it as an effective supplementary tool for independent dose calculation of MR-guided offline and online ART plans, thereby ensuring the safety of patient treatment plans.

Schwann cells (SCs), a type of glial cell in the peripheral nervous system, can serve as a source of mesenchymal stem cells (MSCs) to repair injured pulp. This study aimed to investigate the role of SCs in tooth germ development and repair of pulp injury. We performed RNA-seq and immunofluorescent staining on tooth germs at different developmental stages. The effect of L-type calcium channel (LTCC) blocker nimodipine on SCs odontogenic differentiation was analyzed by real-time polymerase chain reaction and Alizarin Red S staining. We used the PLP1-CreERT2/ Rosa26-GFP tracing mice model to examine the role of SCs and Cav 1.2 in self-repair after pulp injury. SC-specific markers expressed in rat tooth germs at different developmental stages. Nimodipine treatment enhanced mRNA levels of osteogenic markers (DSPP, DMP1, and Runx2) but decreased calcium nodule formation. SCs-derived cells increased following pulp injury and Ca v 1.2 showed a similar response pattern as SCs. The different SCs phenotypes are coordinated in the whole process to ensure tooth development. Blocking the LTCC with nimodipine promoted SCs odontogenic differentiation. Moreover, SCs participate in the process of injured dental pulp repair as a source of MSCs, and Cav 1.2 may regulate this process.

Schwann cells (SCs), a type of glial cell in the peripheral nervous system, can serve as a source of mesenchymal stem cells (MSCs) to repair injured pulp. This study aimed to investigate the role of SCs in tooth germ development and repair of pulp injury. We performed RNA-seq and immunofluorescent staining on tooth germs at different developmental stages. The effect of L-type calcium channel (LTCC) blocker nimodipine on SCs odontogenic differentiation was analyzed by real-time polymerase chain reaction and Alizarin Red S staining. We used the PLP1-CreERT2/ Rosa26-GFP tracing mice model to examine the role of SCs and Cav 1.2 in self-repair after pulp injury. SC-specific markers expressed in rat tooth germs at different developmental stages. Nimodipine treatment enhanced mRNA levels of osteogenic markers (DSPP, DMP1, and Runx2) but decreased calcium nodule formation. SCs-derived cells increased following pulp injury and Ca v 1.2 showed a similar response pattern as SCs. The different SCs phenotypes are coordinated in the whole process to ensure tooth development. Blocking the LTCC with nimodipine promoted SCs odontogenic differentiation. Moreover, SCs participate in the process of injured dental pulp repair as a source of MSCs, and Cav 1.2 may regulate this process.

Schwann cells (SCs), a type of glial cell in the peripheral nervous system, can serve as a source of mesenchymal stem cells (MSCs) to repair injured pulp. This study aimed to investigate the role of SCs in tooth germ development and repair of pulp injury. We performed RNA-seq and immunofluorescent staining on tooth germs at different developmental stages. The effect of L-type calcium channel (LTCC) blocker nimodipine on SCs odontogenic differentiation was analyzed by real-time polymerase chain reaction and Alizarin Red S staining. We used the PLP1-CreERT2/ Rosa26-GFP tracing mice model to examine the role of SCs and Cav 1.2 in self-repair after pulp injury. SC-specific markers expressed in rat tooth germs at different developmental stages. Nimodipine treatment enhanced mRNA levels of osteogenic markers (DSPP, DMP1, and Runx2) but decreased calcium nodule formation. SCs-derived cells increased following pulp injury and Ca v 1.2 showed a similar response pattern as SCs. The different SCs phenotypes are coordinated in the whole process to ensure tooth development. Blocking the LTCC with nimodipine promoted SCs odontogenic differentiation. Moreover, SCs participate in the process of injured dental pulp repair as a source of MSCs, and Cav 1.2 may regulate this process.

Objective:To analyze the dosimetric effects on off-center tumour treatment plan resulting from the MR-Linac-based isocenter position radiotherapy plan.Methods:The cases of 19 patients who were treated in Sun Yat-sen University Cancer Center in 2020 were collected in this study. Two different IMRT plans were designed for each patient with off-center tumor both for group A with planned isocenter position as IMRT and group B with planed target center position as geometric center. The conformity index and homogeneity index of target, the dose normal tissue and the number of MU were compared between two plans.Results:The two IMRT plans met clinical dosimetric requirements. No statistical differences were found both in homogeneity index and conformity index ( P>0.05). Also there was no differences found in doses to normal tissues. However, the MU number (1 149±903, t=2.804, P=0.012) in group A was higher than that in group B (970±652). Conclusions:It is feasible to perform MR-Linac-based off-center treatment plan.

Objective:To investigate the feasibility of applying the ArcherQA three-dimensional (3D) dosimetric verification system in intensity-modulated radiotherapy (IMRT) plans for nasopharyngeal carcinoma (NPC).Methods:A retrospective analysis was conducted for 105 NPC patients′ IMRT plans developed using the Eclipse treatment planning system (TPS). Dose verification was conducted using the ArcherQA system and through portal dosimetry (PD). Moreover, this study compared γ passing rates (criteria: 3 mm/3%, TH = 10%) between ArcherQA and PD and the doses delivered to the target volume ( Dmean, D90%) and organs at risk (OARs) ( Dmean) between ArcherQA and TPS, and analyzed the 3D γ passing rates of each organ at risk calculated by ArcherQA. Results:The average 3D γ passing rate calculated by ArcherQA was (99.04±1.01)%, and the average 2D γ passing rate measured by PD was (99.49±0.78)%, with statistically significant differences ( t=-3.35, P< 0.05). The dosimetric differences to the target volume between ArcherQA and TPS were as follows: the average difference in Dmean to the gross tumor volume (GTV) was (0.57±0.48)%, and the average difference in D90% was (0.65±0.56)%. For the target volume, the average γ passing rate was (97.67±3.43)% for GTV, (97.80±4.35)% for GTVnd-L, (97.82±4.07)% for GTVnd-R, (97.88±2.44)% for CTV1, and (96.64±4.32)% for CTV2. The mean dose difference of each target volume was CTV1 (0.57±0.46)%, GTVnd-L (0.85±0.55)%, GTVnd-R (0.73±0.55)%, and CTV2 (0.88±0.52)%. For OARs, the mean γ passing rate was (99.93±0.22)% for the brainstem, (99.17±2.82)% for the optic chiasm, (100±0)% for the lens, (99.56±1.05)% for the spinal cord, (99.00±2.06)% for the thyroid, and (87.86±10.42)% for the trachea. Statistically significant differences in the average doses to OARs were observed ( t=-14.62 to 4.82, P<0.05), except for those to the left optic nerve, the right hippocampus, and the right parotid gland. Conclusions:Based on the high-performance GPU platform and the Monte Carlo dose algorithm, ArcherQA can provide accurate 3D dose distribution and 3D γ passing rates inside patients according to CT images and provide the dose volume histogram (DVH) of various regions of interest (ROIs). Therefore, the ArcherQA three-dimensional dose verification system can be applied to IMRT plans for NPC. Moreover, it is inducive to improve the treatment efficiency since it does not occupy the accelerator operation time.

Background and Objectives: Dental pulp stem cells (DPSCs) play an important role in the repair of tooth injuries. Electrogenic sodium bicarbonate cotransporter 1 (NBCe1) is a Na＋ -coupled HCO3− transporter encoded by the solute carrier 4A4 (SLC4A4) gene and plays a crucial role in maintaining the pH of DPSCs. Our previous research confirmed that NBCe1 is highly expressed in odontoblasts during the development of the tooth germ. Therefore, in this study, we aimed to investigate the effect of NBCe1 on odontogenic differentiation of DPSCs and further clarify the underlying mechanisms. Methods: and Results: DPSCs were isolated and identified, and the selective NBCe1 inhibitor S0859 was used to treat DPSCs. We used a cell counting Kit-8 assay to detect cell proliferative ability, and intracellular pH was assessed using confocal microscopy. Odontogenic differentiation of DPSCs was analyzed using real-time PCR and Alizarin Red S staining, and the NF-κB pathway was assessed using western blotting. Our results indicated that 10 μM S0859 was the optimal concentration for DPSC induction. Intracellular pH was decreased upon treatment with S0859. The mRNA expressions of DSPP, DMP1, RUNX2, OCN, and OPN were upregulated in the NBCe1 inhibited group compared to the controls. Moreover, NBCe1 inhibition significantly activated the NF-κB pathway, and a NF-κB inhibitor reduced the effect of NBCe1 on DPSC differentiation. Conclusions NBCe1 inhibition significantly promotes odontogenic differentiation of DPSCs, and this process may be regulated by activating the NF-κB signaling pathway.

Objective:To explore the independent prognostic factors of primary osteosarcoma patients under 20 years old after radical surgery, so as to predict the prognosis and survival of patients.Methods:The clinicopathological data of 1 339 patients with primary osteosarcoma diagnosed and registered in the National Cancer Institute Surveillance, epidemiology and outcome database (SEER) from 1984 to 2014 were retrospectively analyzed. Kaplan Meier method was used to calculate the survival rate of patients. Log rank test was used to evaluate the survival difference. Cox multivariate analysis was used to determine the independent prognostic factors of osteosarcoma after radical surgery factor.Results:The results of primary osteosarcoma patients undergoing radical surgery found that 34 cases (2.54%) aged 0-5 years old, 236 cases (17.63%) aged 6-10 years old, and 600 cases (44.81%) aged 11-15 years old and 469 cases (35.02%) aged 16-20 years old. The median survival time was 68 months. Among them, 757(56.53%) were male and 582(43.47%) were female. Among the 1 339 cases, 986 were white (73.64%), followed by black 230(17.18%), and 123 other races (9.18%). Multivariate analysis revealed that males ( HR=1.242; 95% CI:1.024-1.505), axial osteosarcoma ( HR=1.589; 95% CI:1.179-2.166), and regional invasion of osteosarcoma ( HR=1.470; 95% CI:1.156-1.870), distant metastasis ( HR=3.536; 95% CI:2.725-4.589) were independent risk factors for overall survival. Other types of osteosarcoma ( HR=0.471; 95% CI:0.285-0.779) were independent protective factors for overall survival. Conclusions:Based on the SEER database, this study identified independent prognostic factors for patients with primary osteosarcoma under the age of 20 who underwent radical surgery, which will help clinicians formulate individualized medical strategies and predict patients′ prognosis.

Objective:To investigate the clinical feasibility of the Unity radiotherapy system guided by magnetic resonance imaging.Methods:Twenty-four patients were enrolled and received a total of 384 fractions of treatment at Unity system. According to the treatment site, all patients were divided into head-neck, abdomen-thorax, pelvic, spine and limb groups. The patients were set-up without external laser. And then, the time required at different stages in online treatment process and the registration error of each fraction were separately calculated. The geometric deformations of MR images were weekly measured by using MR geometric deformation phantom. At last, the Arccheck was used to perform the dose verification of reference plan, online plan and offline plan.Results:The mean duration of radiotherapy in the five groups were 29.1, 27.6, 26.6, 25.6 and 32.0 min, respectively. The set-up errors in the left-right, superior-inferior and anterior-posterior direction in the five groups were: head-neck group (0.08±0.06 cm, 0.16±0.13 cm, 0.08±0.05 cm), abdomen-thorax group (0.23±0.18 cm, 0.50±0.47 cm, 0.12±0.1 cm), pelvic group (0.25±0.19 cm, 0.32±0.25 cm, 0.11±0.09 cm), spine group (0.46±0.38 cm, 0.26±0.26 cm, 0.13±0.07 cm) and limb group (0.33±0.30 cm, 0.34±0.23 cm, 0.08±0.06 cm), respectively. In the central region, the geometric deformation of MR was less than 0.3 mm, and that of the sphere with a diameter of 500 mm was less than 2.1 mm. The meanγ pass rate of the reference plan, online plan and offline plan were 97.92%, 97.84% and 94.58%, respectively.Conclusions:MR-guided radiotherapy has great potential for clinical application, whereas the process of Unity system is relatively complex. The synergy of different departments has a great impact on the treatment, which needs further optimization.