• Korean Journal of Veterinary Research
• /
• v.40 no.4
• /
• pp.665-670
• /
• 2000

The present study was undertaken to investigate the morphological characteristics of the suprachiasmatic nucleus (SCN) of the Korean native goat by cresyl violet stain. The SCN was located ventrolateral to the third ventricle and dorsal to the optic chiasm. This nucleus was showed carrot form in longitudinal section. Its size was 1.8 mm in length, 0.9 mm in maximum height and 1.6 mm in maximum width. In coronal sections, the SCN shaped very thin plate in rostral part, but it was changed to sweet-potato form in middle part, and ornamental jade form in caudal part. The size of SCN was larger in caudal part than in rostral part. The size of the neuron of SCN was about $10{\mu}m$ in diameter with round or oval shape. The boundary of SCN was not firmly defined in caudal part because the neurons were dispersed into the hypothalamic region. It is concluded that the SCN of the Korean native goat has a morphological characteristics.

• Journal of Radiation Protection and Research
• /
• v.43 no.2
• /
• pp.59-65
• /
• 2018

Background: We analyzed changes in the doses, structure volumes, and dose-volume histograms (DVHs) when data were transferred from one commercial treatment planning system (TPS) to another commercial TPS. Materials and Methods: A total of 22 volumetric modulated arc therapy (VMAT) plans for nasopharyngeal cancer were generated with the Eclipse system using 6-MV photon beams. The computed tomography (CT) images, dose distributions, and structure information, including the planning target volume (PTV) and organs at risk (OARs), were transferred from the Eclipse to the MRIdian system in digital imaging and communications in medicine (DICOM) format. Thereafter, DVHs of the OARs and PTVs were generated in the MRIdian system. The structure volumes, dose distributions, and DVHs were compared between the MRIdian and Eclipse systems. Results and Discussion: The dose differences between the two systems were negligible (average matching ratio for every voxel with a 0.1% dose difference criterion = $100.0{\pm}0.0%$). However, the structure volumes significantly differed between the MRIdian and Eclipse systems (volume differences of $743.21{\pm}461.91%$ for the optic chiasm and $8.98{\pm}1.98%$ for the PTV). Compared to the Eclipse system, the MRIdian system generally overestimated the structure volumes (all, p < 0.001). The DVHs that were plotted using the relative structure volumes exhibited small differences between the MRIdian and Eclipse systems. In contrast, the DVHs that were plotted using the absolute structure volumes showed large differences between the two TPSs. Conclusion: DVH interpretation between two TPSs should be performed using DVHs plotted with the absolute dose and absolute volume, rather than the relative values.

• The Journal of Korean Society for Radiation Therapy
• /
• v.30 no.1_2
• /
• pp.117-128
• /
• 2018

Purpose : To evaluate the usability of plan transfer between TOMO HD and Radixact, we compared the differences of dose in transferred plans by evaluating the dose of normal organ and target. TOMO HDA and Radixact. The completed plans were transferred each other and we compared the differences of dose by evaluating the DVH of each plans. Materials and Methods : We planned 4 different plans assuming the treatment of 2 cases in Head and Neck Cancer and 2 cases Prostate cancer. Each plan was designed so that 95 % of the prescription dose was irradiated over 99 % of the target volume, and the normal organ constraints dose was based on the SMC tolerance dose protocol. Each plan was transferred to each equipment and DVH(dose volume histogram) analysis of the transferred plans was compared and evaluated. Results : The Mean dose of CTV and GTV was increased and decreased in the transferred plans, but there was no significant differences. The target coverage of CTV and GTV was decreased in all cases of transferred plans from TOMO HAD to Radixact, and the change of CI and HI in CTV was within 0.1. Normal organ dose was increased in most cases when transferring from HAD to Radixact in both treatment plans. Conclusion : According to the results of this experiment, the target coverage was above the standard and the normal organ dose was almost same or decreased when transferring the plans from Radixact to HDA equipment. However the target coverage was reduced when transferring the plans from HDA to Radixact and there was an increase in dose in normal organs that could cause sever side effects such as Optic Chiasm ($D_{max}$1.38 Gy), Bladder ($D_{max}$3.07 Gy), Penile Bulb ($D_{max}$1.14 Gy). Therefore, it is necessary to pay attention to the dose change when transferring the plan and one-time transfer due to equipment inspection will be useful for efficient radiation therapy, but if the transferred treatment plans continue for several consecutive days, the treatment plan should be resumed.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.2
• /
• pp.281-287
• /
• 2014

Purpose : The purpose of this study is to compare the plan quality of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for the treatment of orbital lymphoma. IMRT, partial single arc(SA) and partial-double arc(DA) VMAT plans for four patients with orbital lymphoma treated at our institution were used for this study. Conformity Index(CI), Paddick's Conformity Index(PCI) and Homogeneity Index(HI) of planning target volume(PTV) were used to evaluate dosimetric quality of each plan. The Monitor Unit (MU), treatment time and dose of ipsilateral lens from each type of plan were measured for comparison. Materials and Methods : The CI of PTV for IMRT, SA and DA were measured as 0.88, 0.86, 0.92. The PCI of DA was the lowest as 1.33. Also HI of DA was the lowest in measured plans as 1.15. Mean dose of lens, lacrimal gland, optic chiasm, the opposite optic nerve and both orbit was analyzed with V30, V20, V10, V5. The result showed that the lowest dose in IMRT highest in SA in opposite lens, lacrimal gland, optic nerve, orbit. Results : Treatment time and average MU of IMRT was about three times higher than SA. Conclusion : Considering the superior plan quality as well as the delivery efficiency of VMAT compared with that of IMRT, VMAT may be the preferred modality for treating orbital lymphoma.

• The Journal of Korean Society for Radiation Therapy
• /
• v.33
• /
• pp.127-135
• /
• 2021

Purpose : The purpose of the study is to evaluate the efficiency of Vertical MLC VMAT plan(VMV plan) Using 273° and 350° collimator angle compare to Complemental MLC VMAT plan(CMV plan) using 20° and 340° collimator angle for nasopharyngeal carcinoma. Materials & Methods : Thirty patients treated for nasopharyngeal carcinoma with the VMAT technique were retrospectively selected. Those cases were planned by Eclipse, PO and AcurosXB Algorithm with two 6MV 360° arcs and Each arc has 273° and 350° of collimator angle. The Complemental MLC VMAT plans are based on existing treatment plans. Those plans have the same parameters of existing treatment plans but collimator angle. For dosimetric evaluation, the dose-volumetric(DV) parameters of the planning target volume (PTV) and organs at risk (OARs) were calculated for all VMAT plans. MCSv(Modulation complexity score of VMAT), MU and treatment time were also compared. In addition, Pearson's correlation analysis was performed to confirm whether there was a correlation between the difference in the MCSv and the difference in each evaluation index of the two treatment plans. Result : In the case of PTV evaluation index, the CI of PTV_67.5 was improved by 3.76% in the VMV Plan, then for OAR, the dose reduction effect of the spinal cord (-14.05%) and brain stem (-9.34%) was remarkable. In addition, the parotid glands (left parotid : -5.38%, right : -5.97%) and visual organs (left optic nerve: -4.88%, right optic nerve: -5.80%, optic chiasm : -6.12%, left lens: -6.12%, right lens: -5.26%), auditory organs (left: -11.74%, right: -12.31%) and thyroid gland (-2.02%) were also confirmed. The difference in MCSv of the two treatment plans showed a significant negative (-) correlation with the difference in CI (r=-0.55) of PTV_54 and the difference in CI (r=-0.43) of PTV_48. Spinal cord (r=0.40), brain stem (r=0.34), and both salivary glands (left: r=0.36, right: r=0.37) showed a positive (+) correlation. (For all the values, p<.05) Conclusion : Compared to the CMV plan, the VMV plan is considered to be helpful in improving the quality of the treatment plan by allowing the MLC to be modulated more efficiently

• The Journal of Korean Society for Radiation Therapy
• /
• v.22 no.2
• /
• pp.97-103
• /
• 2010

Purpose: Treating same region with different modalities there is a limit to evaluate the total absorbed dose of normal tissues. The reason is that it does not support to communication each modalities yet. In this article, it evaluates absorbed dose of the patients who had been treated same region by a tomotherapy and a linear accelerator. Materials and Methods: After reconstructing anatomic structure with a anthropomorphic phantom, administrate 45 Gy to a tumor in linac plan system as well as prescribe 15 Gy in tomotherapy plan system for make an ideal treatment plan. After the plan which made by tomoplan system transfers to the oncentra plan system for reproduce plan under the same condition and realize total treatment plan with summation 45 Gy linac treatment plan. To evaluate the absorbed dose of two different modalities, do a comparative study both a simple summation dose values and integration dose values. Then compare and analyze absorbed dose of normal tissues and a tumor with the patients who had been exposured radiation by above two differents modalities. Results: The result of compared data, in case of minimum dose, there are big different dose values in spleen (12.4%). On the other hand, in case of the maximum dose, it reports big different in a small bowel (10.2%) and a cord (5.8%) in head & neck cancer patients, there presents that oral (20.3%), right lens (7.7%) in minimum dose value. About maximum dose, it represents that spinal (22.5), brain stem (12%), optic chiasm (8.9%), Rt lens (11.5%), mandible (8.1%), pituitary gland (6.2%). In case of Rt abdominal cancer patients, there represents big different minimum dose as Lt kidney (20.3%), stomach (8.1%) about pelvic cancer patients, it reports there are big different in minimum dose as a bladder (15.2%) as well as big different value in maximum dose as a small bowel (5.6%), a bladder (5.5%) in addition, making treatment plan it is able us to get. Conclusion: In case of comparing both simple summation absorbed dose and integration absorbed dose, the minimum dose are represented higher as well as the maximum dose come out lower and the average dose are revealed similar with our expected values data. It is able to evaluate tumor & normal tissue absorbed dose which could had been not realized by treatment plan system. The DVH of interesting region are prescribed lower dose than expected. From now on, it needs to develop the new modality which are able to realize exact dose distribution as well as integration absorbed dose evaluation in same treatment region with different modalities.

• Radiation Oncology Journal
• /
• v.15 no.4
• /
• pp.287-296
• /
• 1997

Purpose : This is study of whether 3-D conformal radiotherapy for carcino-mas of the ethmoid sinus were better than those treated with conventional 2-D plan, Materials and Methods : The 3-D conformal treatment Plans were compared with conventional 2-D plans in 4 patients with malignancy of the ethmoid sinus. Isodose distribution, dose statistics, and dose volume histogram of the planning target volume were used to evaluate differences between 2-D and 3-D plans. In addition. the risk of radiation exposure of surrounding normal critical organs are evaluated by means of point dose calculation and dose volume histogram. Results : 3-D conformal treatment plans for each patient that the better tumor coverages by the planning target volume with improved dose homo-geneity, compared to 2-D conventional treatment Plans in the same Patient. On the other hand, the radiation dose distributions to the surrounding nor-mal tissue organs, such as the orbit and optic nerves are not significantly reduced with our technique, but a substantial sparing in the brain stem and optic chiasm for each patient. Conclusion : Our findings represented the potential advantage of 3-D treatment planning for dose homogeniety as well as sparing of the normal tissue surrounding the tumor. However, further investigational studies are required to define the clinical benefit.

• The Journal of Korean Society for Radiation Therapy
• /
• v.29 no.1
• /
• pp.57-68
• /
• 2017

Purpose: The purpose of this study was to compare volumetric modulated arc therapy(VMAT) with fixed-field intensity modulated radiation therapy(IMRT) using non-coplanar beam when the shape of target is irregular and the location is adjacent to organ at risk(OAR). Materials and Methods: The subjects of this study were a total of 6 patients who had radiation therapy for whole scalp(2 patients), partial scalp(2 patients), and whole ventricle(2 patients) by True Beam STX(Varian Medical Systems, USA). VMAT plans consisted of coplanar or non-coplanar arcs which can minimize the volume of OAR included in beamlets. All fixed-field IMRT plans consisted of non-coplanar beams using more than 2 angles of Couch. Results: The VMAT and IMRT plans were compared with regard to the maximum dose of both lens, both optic nerves, optic chiasm, and brain stem and the mean dose of both eyeballs and hippocampus. VMAT plans showed higher dose than ncIMRT plans at more than 6 of all OARs in every patient, and the ratio was from 1.1 times to 8.2 times. In case of total scalp and partial scalp, the volume of brain which received more than 20 Gy in the VMAT plans was 2 times larger than the volume in the ncIMRT plans. In case of whole ventricle, there was no significant difference. Target coverage was satisfied in both plans($PTV_{100%}=95%$). The maximum dose in target volume and required monitor unit(MU) of ncIMRT were higher than them of VMAT plans. Conclusion: Even though ncIMRT is less efficient than VMAT with regard to required MU and treatment time, the dose to OARs is much lower than VMAT and PTV Coverage is similar with VMAT. If the shape of target is irregular and location is adjacent to OAR, comparison VMAT plan with ncIMRT plan deserves to be considered.

• The Journal of Korean Society for Radiation Therapy
• /
• v.23 no.1
• /
• pp.31-39
• /
• 2011

Purpose: Helical Tomotherapy allows only coplanar beam delivery because it does not allow couch rotation. We investigated a method to introduce non-coplanar beam by tilting a patient's head for Tomotherapy. The aim of this study was to compare intrafractional movement during Tomotherapy between coplanar and non-coplanar patient's setup. Materials and Methods: Helical Tomotherapy was used for treating eight patients with intracranial tumor. The subjects were divided into three groups: one group (coplanar) of 2 patients who lay on S-plate with supine position and wore thermoplastic mask for immobilizing the head, second group (non-coplanar) of 3 patients who lay on S-plate with supine position and whose head was tilted with Variable Axis Baseplate and wore thermoplastic mask, and third group (non-coplanar plus mouthpiece) of 3 patients whose head was tilted and wore a mouthpiece immobilization device and thermoplastic mask. The patients were treated with Tomotherapy after treatment planning with Tomotherapy Planning System. Megavoltage computed tomography (MVCT) was performed before and after treatment, and the intrafractional error was measured with lateral(X), longitudinal(Y), vertical(Z) direction movements and vector ($\sqrt{x^2+y^2+z^2}$) value for assessing overall movement. Results: Intrafractional error was compared among three groups by taking the error of MVCT taken after the treatment. As the correction values (X, Y, Z) between MVCT image taken after treatment and CT-simulation image are close to zero, the patient movement is small. When the mean values of movement of each direction for non-coplanar setup were compared with coplanar setup group, X-axis movement was decreased by 13%, but Y-axis and Z-axis movement were increased by 109% and 88%, respectively. Movements of Y-axis and Z-axis with non-coplanar setup were relatively greater than that of X-axis since a tilted head tended to slip down. The mean of X-axis movement of the group who used a mouthpiece was greater by 9.4% than the group who did not use, but the mean of Y-axis movement was lower by at least 64%, and the mean of Z-axis was lower by at least 67%, and the mean of Z-axis was lower by at least 67%, and the vector was lower by at least 59% with the use of a mouthpiece. Among these 8 patients, one patient whose tumor was located on left frontal lobe and left basal ganglia received reduced radiation dose of 38% in right eye, 23% in left eye, 30% in optic chiasm, 27% in brain stem, and 8% in normal brain with non-coplanar method. Conclusion: Tomotherapy only allows coplanar delivery of IMRT treatment. To complement this shortcoming, Tomotherapy can be used with non-coplanar method by artificially tilting the patient's head and using an oral immobilization instrument to minimize the movement of patient, when intracranial tumor locates near critical organs or has to be treated with high dose radiation.