• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.857-862
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• 2022

The purpose of this study was to evaluate a three-dimensional conformal radiotherapy (3D-CRT) treatment plan with regard to head tilting in whole-brain radiotherapy (WBRT) using TomoDirect (TD) mode in Tomotherapy. WBRT 3D-CRT by TD was compared for a total of five head tilt angles (-20°, -10°, 0°. +10° and +20°). The dose homogeneity index (HI) and prescription dose index (CI) were calculated to confirm the target coverage. The maximum and average doses for critical organs such as the lens, eyeball and parotid glands were calculated for different angles of head tilting. The HI and CI were closet to the result value of 1 at the head tilted angle +10° and +20°. At a head tilted angle of +10°, the dose to the lens and eyeballs decreased by about 74% and about 30%, when compared with the reference angle (0°), respectively. The results of this study suggest that a head angle of +10 with chin-up would save adequate target coverage and reduce exposure dose to the lens.

• Journal of Oral Medicine and Pain
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• v.47 no.3
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• pp.148-151
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• 2022

Obstructive sialadenitis, one of the diseases that most frequently causes swelling and pain in the salivary glands, is mainly caused by structural obstructions. Sialolithiasis is the most frequent cause of the disease, and other causes include calculus formation, duct strictures, foreign bodies, and anatomical variations. Although there is a possibility that facial fillers directly block the salivary ducts, no cases of obstructive sialadenitis associated with them have been reported yet. We report the case of a 34-year-old female patient who complained of recurrent swelling and pain in the left buccal mucosa. She had undergone facial filler injection procedures on her facial area for cosmetic purposes several years before. Based on the findings of magnetic resonance imaging (MRI) and MR sialography, she was diagnosed with obstructive sialadenitis due to facial fillers. Through this case, we should remember to obtain a thorough history including filler treatments in the case of parotid gland swelling. We also suggest proper utilization of advanced imaging such as MRI in evaluating the location of facial fillers.

• Anatomy and Cell Biology
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• v.56 no.3
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• pp.313-321
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• 2023

The details of the facial nerve pattern were clearly explained in the parotid gland (PG), lateral area of the face, and periorbital areas to prevent the unexpected outcome of medical intervention. However, it remains unclear whether information about the zygomatico-buccal plexus (ZBP) in the masseteric and buccal regions. Therefore, this study aimed to help clinicians avoid this ZBP injury by predicting their common location. This study was conducted in forty-two hemifaces of twenty-nine embalmed cadavers by conventional dissection. The characteristics of the buccal branch (BB) and the ZBP were investigated in the mid-face region. The results presented that the BB gave 2-5 branches to emerge from the PG. According to the masseteric and buccal regions, the BB were arranged into ZBP in three patterns including an incomplete loop (11.9%), a single-loop (31.0%), and a multi-loop (57.1%). The mean distance and diameter of the medial line of the ZBP at the corner of the mouth level were 31.6 (6.7) and 1.5 (0.6) mm respectively, while at the alar base level were 22.5 (4.3) and 1.1 (0.6) mm respectively. Moreover, the angular nerve arose from the superior portion of the ZBP at the alar base level. The BB formed a multiloop mostly and showed a constant medial line of ZBP in an area approximately 30 mm lateral to the corner of the mouth, and 20 mm lateral to the alar base. Therefore, it is recommended that physicians should be very careful when performing facial rejuvenation in the mid-face region.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.43-51
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• 2001

Purpose: In this study, we compared the quantitative characteristics of dynamic salivary gland scintigraphy with static scintigraphy in patients with clinical sicca syndrome using Tc-99m pertechnetate. Materials and Methods: Fifty-two parotid glands and 52 submandibular glands out of 26 patients with clinical sicca syndrome were studied by dynamic and static salivary gland scintigraphy. Ten normal volunteers were also studied as a control group for comparison of scintigraphic parameters. Ten minutes after injection of 370 MBq Tc-99m pertechnetate, we obtained pre-stimulus static images for a few minutes. Then dynamic salivary gland scintigraphy with lemon juice stimulation was performed for 20 minutes. Finally we obtained post-stimulus static images after dynamic images. On dynamic study, functional parameters such as uptake rate, secretion rate and re-uptake rate were calculated. The results of dynamic study and static images were compared. Results: On dynamic study, we could obtain functional parameters of salivary glands successfully. On dynamic study, 22 parotid glands and 22 submandibular glands out of each of 52 glands are abnormal. The static images demonstrated somewhat different results, of which reasons we could assume via dynamic study. Conclusion: Dynamic salivary gland scintigraphy using Tc-99m perechnetate were more functional than static images and might be useful in the assessment of the functional change of the salivary gland in patients with clinical sicca syndrome.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.253-264
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• 1990

The purpose of this study was to estimate the distribution of absorbed doses of each important organs of head and neck region in panoramic radiography. Radiation dosimetry at internal anatomic sites and skin surfaces of phantom (RT-210 Humanoid Head & Neck Section/sup R/) was performed with lithium fluoride (TLD-100/sup R/) thermoluminescent dosimeters according to change of kilovoltage (65kVp, 75kVp and 85kVp) with 4 miliamperage and 20 second exposure time. The results obtained were as follows; Radiation absorbed doses of internal anatomic sites were presented the highest doses of 1.04 mGy, 1.065 mGy and 2.09 mGy in nasopharynx, relatively high doses of 0.525 mGy, 0.59 mGy and 1.108 mGy in deep lobe of parotid gland, 0.481 mGy, 0.68 mGy and 1.191 mGy in submandibular gland. But there were comparatively low doses of 0.172 mGy and 0.128 mGy in eyes and thyroid gland that absorbed dose was estimated at 85kVp. Radiation absorbed doses of skin surfaces were presented the highest doses of 1. 263 mGy, 1.538 mGy and 2.952 mGy in back side of first cervical vertebra and relatively high doses of 0.267 mGy, 0.401 mGy and 0.481 mGy in parotid gland. But there were comparatively low doses of 0.057 mGy, 0.068 mGy and 0.081 mGy in philtrum and 0.059 mGy in middle portion of chin that absorbed dose was estimated at 85kVp. According to increase of kilovoltage, the radiation absorbed doses were increased 1.1 times when kilovolt age changes from 65kVp to 75kVp and 1.9 times when kilovolt age changes from 75kVp to 85kVp at internal anatomic sites. According to increase of kilovoltage, the radiation absorbed doses were increased 1.3 times when kilovolt age changes from 65kVp to 75kVp and 1.6 times when kilovoltage changes from 75kVp to 85kVp at skin surfaces.

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.365-373
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• 2007

Destruction of oral soft and hard tissues and resulting problems seriously affect the life quality of xerostomic patients. Although artificial saliva is the only regimen for xerostomic patients with totally abolished salivary glands, currently available artificial salivas give restricted satisfaction to patients. The purpose of this study was to contribute to the development of ideal artificial saliva through comparing viscosity and wettability between CMC solutions and human saliva. Commercially-available CMC is dissolved in simulated salivary buffer (SSB) and distilled deionized water (DDW). Various properties of human whole saliva, human glandular saliva, and a CMC-based saliva substitutes known as Salivart and Moi-Stir were compared with those of CMC solutions. Viscosity was measured with a cone-and-plate digital viscometer at six different shear rates, while wettability on acrylic resin and Co-Cr alloy was determined by the contact angle. The obtained results were as follows: 1. The viscosity of CMC solutions was proportional to CMC concentration, with 0.5% CMC solution displaying similar viscosity to stimulated whole saliva. Where as a decrease in contact angle was found with increasing CMC concentration. 2. The viscosity of human saliva was found to be inversely proportional to shear rate, a non-Newtonian (pseudoplastic) trait of biological fluids. The mean viscosity values at various shear rates increased as follows: stimulated parotid saliva, stimulated whole saliva, unstimulated whole saliva, stimulated submandibular-sublingual saliva. 3. Contact angles of human saliva on the tested solid phases were inversely correlated with viscosity, namely decreasing in the order stimulated parotid saliva, stimulated whole saliva, unstimulated whole saliva, stimulated submandibular-sublingual saliva. 4. Boiled CMC dissolved in SSB (CMC-SSB) had a lower viscosity than CMC-SSB (P < 0.01 at shear rate of $90s^{-1}$). 5. For human saliva, contact angles on acrylic resin were significantly lower than those on Co-Cr alloy (P < 0.01). 6. Comparing CMC solutions with human saliva, the contact angles between acrylic resin and human saliva solutions were significantly lower than those between acrylic resin and CMC solutions, including Salivart and Moi-Stir (P <0.01). The effectiveness of CMC solutions in terms of their rheological properties was objectively confirmed, indicating a vital role for CMC in the development of effective salivary substitutes.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.127-135
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• 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
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• v.25 no.1
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• pp.1-8
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• 2013

Purpose: A selection of proper energy in treatment planning is very important because of having different dose distribution in body as photon energy. In generally, the low energy photon has been used in intensity-modulated radiation therapy (IMRT) for head and neck (H&N) cancer. The aim of this study was to evaluate the effect of partially used high energy photon at posterior oblique fields on IMRT plan for H&N cancer. Materials and Methods: The study was carried out on 10 patients (nasopharyngeal cancer 5, tonsilar cancer 5) treated with IMRT in Seoul National University Bundang Hospital. CT images were acquired 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). Two plans were generated under same planing objectives, dose volume constraints, and eight fields setting: (1) The low energy plan (LEP) created using 6 MV beam alone, (2) the partially used high energy plan (PHEP) created partially using 15 MV beam at two posterior oblique fields with deeper penetration depths, while 6 MV beam was used at the rest of fields. The plans for LEP and PHEP were compared in terms of coverage, conformity index (CI) and homogeneity index (HI) for planning target volume (PTV). For organs at risk (OARs), $D_{mean}$ and $D_{50%}$ were analyzed on both parotid glands and $D_{max}$, $D_{1%}$ for spinal cord were analyzed. Integral dose (ID) and total monitor unit (MU) were compared as addition parameters. For the comparing dose to normal tissue of posterior neck, the posterior-normal tissue volume (P-NTV) was set on the patients respectively. The $D_{mean}$, $V_{20Gy}$ and $V_{25Gy}$ for P-NTV were evaluated by using dose volume histogram (DVH). Results: The dose distributions were similar with regard to coverage, CI and HI for PTV between the LEP and PHEP. No evident difference was observed in the spinal cord. However, the $D_{mean}$, $D_{50%}$ for both parotid gland were slightly reduced by 0.6%, 0.7% in PHEP. The ID was reduced by 1.1% in PHEP, and total MU for PHEP was 1.8% lower than that for LEP. In the P-NTV, the $D_{mean}$, $V_{20Gy}$ and $V_{25Gy}$ of the PHEP were 1.6%, 1.8% and 2.9% lower than those of LEP. Conclusion: Dose to some OARs and a normal tissue, total monitor unit were reduced in IMRT plan with partially used high energy photon. Although these reduction are unclear how have a clinical benefit to patient, application of the partially used high energy photon could improve the overall plan quality of IMRT for head and neck cancer.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.367-375
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• 1998

Purpose : Xerostomia is a complication met by almost all patients who have radiotherapy for cancers of head and neck. Many studies for prevention of xerostomia will be necessary. Radiation-induced acute response of salivary glands has been defined as interphase death or apoptosis. Increased intracellular calcium level have an important role in radiation-induced apoptosis. Calcium channel blocker may prevent radiation-induced apoptosis of salivary glands. This study was designed to evaluate the effectiveness of diltiazem known as calcium channel blocker and pentoxifylline with inhibition of inflammatory response on the apoptosis as an acute response of radiation in rat salivary glands. Materials and Methods : Sprague-Dawley rats with about body weight 200-250 g were divided into 5 study groups : control, radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation. The diltiazen and pentoxifylline were injected intraperitoneally 20 mg/kg and 50 mg/kg, 30 and 20 mimute before irradiation. respectively. Irradiation was given with a 4 MV linear accelerator. The 1600 cGy of radiation was delivered in a single fraction through a single anterior portal encompassing the entire neck. After 24 h of irradiation, rats were sacrificed and parotid and submandibular glands were removed and stained with hematoxylin and eosin. The quantification of apoptosis was performed by microscopic examination of stained tissue sections at a magnification of 200X and the percentage of apoptotic cell was calculated. Results : On parotid glands, the percentage of apoptosis by radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation were 1.72$\%$ (8.35/486), 0.64$\%$ (2.9/453), 0.23$\%$ (1.2/516), and 0.28$\%$ (1.1/399), respectively. The apoptosis was markedly reduced in the groups receiving drugs compared with groups receivinge, radiation alone (p<0.05). In serous cell of submandibular glands, the percentages of apoptosis of radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation were 1.94$\%$ (l1/567), 0.34$\%$ (1.9/554), 0.28$\%$ (1.8/637), and 0.22$\%$ (1.3/601), respectively. In the mucus cell of submandibular glands, the percentages of apoptosis were 0.92$\%$ (5.1/552), 0.41$\%$ (2.5/612), 0.29$\%$ (1.3/455), and 0.18$\%$ (1.0/562), respectively. The apoptosis was markedly reduced in the serous glands (p<0.05), but there was no difference in development of apoptosis in each group of mucus gland. Conclusion : These results suggest that radiation-induced apoptosis of serous cells of salivary glands may be decreased by diltiazem and pentoxifylline administration.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.21-30
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• 2022

Purpose: The purpose of this study is to evaluate the effectiveness of oral positioning stent, the BinkieRT^TM in radiation treatment for head and neck cancer patients in terms of tongue positions reproducibility, tongue doses and material properties. Materials and Methods: 24 cases using BinkieRT^TM during radiation treatments were enrolled. The tongue was contoured on planning CT and CBCT images taken every 3 days during treatment, and then the DSC and center of tongue shift values were analyzed to evaluate the reproducibility of the tongue. The tongue dose was compared in terms of dose distribution when using BinkieRT^TM and different type of oral stents (mouthpiece, paraffin wax). Randomly selected respective 10 patients were measured tongue doses of initial treatment plan for nasal cavity and unilateral parotid cancer. Finally, In terms of material evaluation, HU and relative electron density were identified in RTPS. Results: As a result of DSC analysis, it was 0.8 ± 0.07, skewness -0.8, kurtosis 0.61, and 95% CI was 0.79~0.82. To analyze the deviation of the central tongue shift during the treatment period, a 95% confidence interval for shift in the LR, SI, and AP directions were indicated, and a one-sample t-test for 0, which is an ideal value in the deviation(n=144). As a result of the t-test, the mean and SD in the LR and SI directions were 0.01 ± 0.14 cm (p→.05), 0.03 ± 0.25 cm (p→.05), and -0.08 ± 0.25 cm (p ←.05) in the AP direction. In the case of unilateral parotid cancer patients, the Dmean to the tongue of patients using BinkieRT^TM was 16.92% ± 3.58% compared to the prescribed dose, and 23.99% ± 10.86% of patients with Paraffin Wax, indicating that the tongue dose was relatively lower when using BinkieRT^TM (p←.05). On the other hand, among nasal cavity cancer patients, the Dmean of tongue dose for patients who used BinkieRT^TM was 4.4% ± 5.6%, and for those who used mouthpiece, 5.9% ± 6.8%, but it was not statistically significant (p→.05). The relative electron density of Paraffin Wax, BinkieRT^TM and Putty is 0.94, 0.99, 1.26 and the mass density is 0.95, 0.99 and 1.32 (g/cc), Transmission Factor is 0.99, 0.98, 0.96 respectively. Conclusion: The result of the tongue DSC analysis over the treatment period was about 0.8 and Deviation of the center of tongue shifts were within 0.2 cm, the reproducibility was more likely excellent. In the case of unilateral head and neck cancer patients, it was found that the use of BinkieRT^TM rather than Paraffin Wax or Putty can reduce the unnecessary dose irradiated to the tongue. This study might be useful to understand of BinkieRT^TM's properties and advantages. And also it could be another considered option as oral stent to keep the reproducibility of tongue and reducing dose during head and neck radiation treatments.