• 대한방사선치료학회지
• /
• 제16권2호
• /
• pp.1-8
• /
• 2004

목적 : 전신 정위적 방사선 수술환자 치료 시 환자의 set up을 정확히 확인하고 평가하는 것은 치료 성적을 좌우 하는데 중요한 요소이다. 특히 폐암 환자의 경우 호흡 등에 의한 종양의 움직임으로 인해서 L-gram이나 EPID를 이용하여 정확한 위치를 확인하는데는 여러 가지 어려움이 있다. 이러한 문제점들에 대하여 verification system(exactrac)을 이용하여 set up의 정확성을 확인해 보고자 한다. 대상 및 방법 : Body frame(elekta, sweden)을 이용하여 전신 정위적 방사선 수술을 받는 폐암 환자 6명을 대상으로 (ABC tool을 사용한 환자 5명과 사용 안한 환자1명) 기존의 L-gram과 EPIDs로 image를 획득하여 Ant, Lat image를 비교하여 환자의 set-up을 확인하고 CT에서 얻은 DRR image와 Verification system(exactrac)의 X-ray image를 얻어서 두image를 3차원적으로 fusion하여 그 좌표 값(vertical, longitudinal, lateral)을 분석하고 기존의 방법과의 차이를 확인하였다. 결과 : L-gram과 EPIDs로는 정확한 좌표 값보다는 주관적으로 Set up의 정확성 여부를 판단하여 치료할 수 있었지만 Verification system(exactrac)을 이용하여 확인한 결과 치료환자의 Set up 전, 후의 좌표 값(vertical, longitudinal, lateral)이 0.5cm이내에 포함되는 것을 볼 수 있었고 좌표 값의 차이를 시각적이고 객관적으로 평가할 수 있어서 Set up의 정확성을 판단하는 데 유용했다. 결론 : Verification system(exactrac)을 사용하면 환자의 Set up이 정확한 지 치료 전 또는 중간에도 시각적인 확인이 가능한 장점이 있지만 기존의 방법보단 확인과정이 조금 복잡하고 CT scan 시 3mm 이내로 해야 하며 X-ray image가 선명하게 나타나야 된다는 단점이 있다. 이러한 문제점만 해결된다면 Set up의 정확성을 쉽게 확인할 수 있어서 치료 시 많은 도움이 되리라고 생각된다.

• 대한방사선치료학회지
• /
• 제29권2호
• /
• pp.33-41
• /
• 2017

목 적: 종양에는 최대한의 선량을 부여하고 주변의 정상조직에는 최소한의 선량이 조사되도록 부작용을 줄이는 목적으로 방사선 치료기술이 발전함에 따라 다양한 치료계획 및 치료 방법이 개발되고 있다. 방사선 치료 시 CT(Computed tomography)와 MRI(Magnetic resonance imaging)영상의 융합은 종양에 선량을 전달하는데 커다란 역할을 한다. 본 연구의 목적은 치료계획 시 자체 제작한 팬톰을 이용하여 CT와 MRI영상들의 융합을 통해 영상의 재현성 및 유용성을 평가하고 획득한 영상에서 타겟 선량을 비교, 분석해보고자 한다. 대상 및 방법: 자체 제작한 팬톰을 이용하여 CT 촬영을 하고, 자장의 세기가 다른 1.5T 와 3.0T의 MRI 촬영을 하여 영상을 획득한다. CT 촬영을 한 팬톰의 영상과 각기 다른 자장의 세기로 촬영한 팬톰의 MRI영상에서 팬톰 내에 존재하는 작은 홀의 크기 및 용적의 재현성을 비교하고, 임의의 타겟에서 선량 변화를 비교, 분석한다. 결 과: 13개의 작은 홀 직경은 CT 촬영에서 최대 31 mm, 최소 27.54 mm를 나타냈으며, 실제 제작한 것과 비교하여 평균 29.28 mm 1 % 이내로 측정되었다. 1.5T MRI 퓨전 영상에서는 최대 31.65 mm, 최소 24.3 mm를 나타냈으며, 평균 28.8 mm 1 % 이내로 측정되었다. 3.0T MRI 퓨전 영상에서는 최대 30.2 mm, 최소 27.92 mm를 나타냈으며, 평균 29.41 mm 1.3 % 이내로 측정되었다. 타겟의 조사된 선량변화는 CT에서 95.9-102.1 %, CT-1.5T MRI 퓨전영상에서 93.1-101.4 %, CT-3.0T MRI 퓨전영상에서는 96-102 %의 선량변화를 보였다. 결 론: CT 및 MRI는 영상획득 시 다른 알고리즘이 적용된다. 또한 인체의 장기는 각기 다른 밀도를 가지고 있으므로 영상 획득 시 이미지 왜곡이 발생할 수 있다. 이러한 부정확한 영상의 묘사는 타겟의 용적범위 및 선량에 영향을 주기 때문에 정확한 타겟의 용적과 위치는 불필요한 선량이 조사되는 것을 방지하며, 치료계획 시 오차를 방지할 수 있다. 즉 CT와 MRI 영상이 가지고 있는 영상 표출 알고리즘의 장점을 이용하여 치료계획에 적용해야 할 것이다.

• 핵의학기술
• /
• 제21권2호
• /
• pp.31-36
• /
• 2017

최근 PET/CT 장비의 성능의 발전과 다양한 기법의 개발로 민감도와 해상도등 영상 품질을 개선할 수 있게 되었다. 본 논문에서는 GE사의 Discovery IQ 장비의 Q.Clear (a fully convergent iterative reconstruction) 기법을 이용하여 영상의 질 향상에 유용성이 있는지 알아보고자 한다. 장비는 Discovery IQ (GE Healthcare, MI, USA)를 사용하였다. NEMA IEC Body Phantom의 배후방사능과 열소 체적(10 mm, 13 mm, 17 mm, 22 mm)의 비를 1:4로 하고 3분간 촬영하여 VPHDs (VUE Point High-Definition SharpIR)와 Q.Clear의 대조도를 비교 분석하였다. PET/SPECT Performance Phantom에 $^{18}F-FDG$를 187 MBq을 주입 후 4분간 촬영하여 해상도와 균일도를 비교 분석하였다. 그리고 100명의 임상 환자에서 질환의 종류와 상관없이 2 cm 미만의 작은 병소의 SUVmax를 측정하여 t-test 통계분석하였다. NEMA IEC Body Phantom에서 VPHDs와 Q.Clear의 대조도가 $63.6{\pm}5.7%$, $75{\pm}4.8%$로 나왔고 PET/SPECT Performance Phantom에서 해상도는 VPHDs가 9.2 mm, Q.Clear가 7.3 mm로 나왔다. 균일도는 Q.Clear가 10.8% 더 우수하였다. 임상 환자의 t-test 통계 결과 p-value가 0.021로 유의한 차이가 있었다. 임상환자에서 SUVmax는 Q.Clear에서 높게 측정 되었으며, 신호대 잡음 비도 우수하였다. 이는 부분체적효과의 영향을 줄였기 때문으로 볼 수 있다. Phantom test와 임상 환자의 결과 모두 Q.Clear를 적용 하였을 때 영상품질이 향상된 것을 확인하였다. 이러한 영상 품질 향상은 병소를 더욱 정확하게 발견할 수 있고 나아가 선량저감과 환자평가 그리고 영상 분석 등 다양한 방면에서 활용할 수 있을 것으로 사료된다.

• 대한의용생체공학회:의공학회지
• /
• 제25권6호
• /
• pp.519-523
• /
• 2004

골다공증이 있는 대퇴골두 해면골과 골다공증이 없는 대퇴골두 해면골의 특성을 평가하고자 미세단층촬영기 및 유한요소모델을 이용하여 해면골을 미세구조 특성과 기계적 특성을 비교 및 분석하였다. 골다공증이 있는 대퇴골두는 골밀도를 측정하여 T-score 값이 -2.5 이상인 시편 15개를 사용했으며, 골다공증이 없는 대퇴골두는 사망전 골다공증으로 인한 병력이 없었던 사체 4구에서 대퇴골두 5개를 획득하여 사용하였다. 대퇴골두 해면골의 미세구조 특성을 분석하기 위해서 미세단층촬영기를 이용하여 골다공증이 있는 대퇴골두와 골다공증이 없는 대퇴골두를 촬영하여 형태학적 지수(histomorphometry index)를 구했고, 미세단층촬영기에 의해서 획득된 미세영상(pixel size=21.31㎛)을 바탕으로 유한요소모델을 재건하여 기계적 특성을 구하였다. 형태학적지수는 골다공증이 없는 대퇴골두가 골다공증이 있는 대퇴골두에 비해서 골소주 두께, 골 체적, 골 체적비, 이방성 정도 그리고 골소주 개수가 증가했으며, 골소주 간격과 구조모델지수는 감소했다. 기계적특성 지수는 골다공증이 없는 대퇴골두 해면골 시편에서 반력, 표면응력 그리고 영률이 높게 분석되었다. 골다공증이 있는 대퇴골두 해면골 시편에서 미세구조 특성이 퇴화되며, 기계적 특성이 감소된다는 사실을 알수 있었다.

• Journal of Oral Medicine and Pain
• /
• 제23권4호
• /
• pp.457-473
• /
• 1998

This study was performed to investigate the morophological and positional correlation between the upper cervical vertebra, the oral structures and the pharyngeal tissues, and the correlation of these anatomical structures with dental features, such as teeth wear area nad tooth contact status, etc. Seventy patients with temporamandibular disorders and sixty three dental students without any signs and symptoms in head and neck region were selected for this study. All they had natural dentition without any fixed and removable protheses. Teeth wear area and arch width wre measured from the upper dental cast, tooth contact status were observed by T-Scan system$^\textregistered$ and four cephaloradiograpohs were taken from four head postures, namely, natural(NHP), forward(FHP), upward(UHP), and downward head postiure(DHP). 22 cephalometric items were measured on the films and the data were processed with SAS statistical program. The result of this study were as follows : 1. In normal group, angle of cervical vertebra tangent and of between hard and soft palate were broader in female subjects than those in male subjacets, but distance from subocciput to axis, size of soft palate, and pharyngeal space width were larger in male subjects. 2. In normal group with natural head posture, the items correlated each others from the three anatomical regions were distance between first nad second vertebra in posterior part, distance from the lingual surface of lower anterior teeth to anterior surface of soft palate, and distance from the hyoid bone to third vertebra. 3. Three set of items showed significant correlation each other in the four head postures in normal group. First set was the angle between hard and soft palate and the idstance from subocciput to posterior arch of first vertebra, second set was the distance between first and second vertebra in posterior part and the teeth wear area, third set was number and force of tooth contact and length of soft palate and distance from anterior tip of hyoid bone to mandibular plane.

• Journal of Oral Medicine and Pain
• /
• 제18권2호
• /
• pp.71-79
• /
• 1993

Many types of occlusal splints are used for treatment of craniomandibular disorders. Most widely used splint among them is flat-type centric relation splint. Insertion of splint into the mouth may cause increasing of vertical dimension, masticatory muscle realignment and rearrangement of maxillo-mandibular relationship, so as a result of splint treatment, occlusal relation may vary whether you like it or not. From this point of view, occlusal state of patient shold be frequently monitored to prevent undesired or harmful effect during occlusal splint therapy. The purpose of this study was to investigate the effect of occlusal splint, especially centric relation splint, on the occlusal contact state after 3 months treatment. 32 patients with craniomandibular disorders who had unilateral symptoms participated in this study. To observe and record occlusal contact state, the author used T-Scan system (Tekscan Co. U.S.A.) at both pretreatment and posttreatment. The recorded date were analyzed with regard to contact number, contact force and contact time, change of anterior tooth contact and coincidence of first contact point with affected side were observed, too. Aan last, the subjects were divided into 2 groups and compared, according to average value of VAS index, with respect to joint pain, sound and limitation of movement, respectively. The collected date were statistically processed with SPSS and the result as follows : 1. Total occlusal contact number and force were not changed by occlusal splint therapy but total occlusal contact time decreased slightly. 2. There was a tendency of increasing number of subjects with anterior tooth contact after treatment and change of first contact point side were observed in as many as 40.6% of subjects. 3. There were no difference between higher and lower group of VAS index, and between pretreatment and posttreatment in each group, either.

• Journal of Oral Medicine and Pain
• /
• 제19권2호
• /
• pp.181-192
• /
• 1994

There have been many different theories on the etiology of temporomandibular disorders(TMDs). The objective of the study was to investigate the effects of occlusal fctors and recent life event changes as prediposing fctor on the development of temporomandibjlar disorders. To evaluate the above predisposing factor, the author used T-scan system(Tekscan Co. U.S.A.) for quantitative occlusal analysis, clinical examination for occlusal state and Social Readjustment Rating Scale(SRRS) for recent life event change units (LCU). 63 patients with TMDs and 57 patients with malocclusion presented at Wonkwang University Dental Hospital participated in this study. The subjects were grouped by Angle's classification and presence of absence of TMDs and parafunctional oral habits. Data gained with regard to contact number, contact force, contact time, occlusal state(number of total teeth and occluding teeth, overjet, overbite) and occlusal interferences (protrusive posterior contact, nonworking side interference, and RCP-ICP slide) and recent life event changes. The data were processed and analysed by SAS statistical package program, The results of this study were as follows : 1. There were no significant differences on both quantitative occlusal contact analysis and occlusal state between TMDs group and Angle's malocclusion group. Also, there were no differences among the Angle's classifications. But amount of overjet in TMDs group were more greater than that of malocclusion group. 2. There was no difference on protrusive posterior contact, and balancing contact between TMDs group and Angle's malocclusion group. Premature contact was more frequent in malocclusion group, but RCP-ICP slide was more frequent in TMDs group. And RCP-ICP slide was more freqent in Angle's class II malocclusion than Angle's I or III malocclusion. 3. Life changes units in TMDs group were higher than those in malocclusion group. And recent life change units in group with parafunctional oral habit were higher than those in group without parafunctional oral habits. Clenching was the most common habit among parafunctional oral habits.

• The Journal of Advanced Prosthodontics
• /
• 제10권5호
• /
• pp.354-360
• /
• 2018

PURPOSE. To compare and analyze trueness and precision of provisional crowns made using stereolithography apparatus and subtractive technology. MATERIALS AND METHODS. Digital impressions were made using a master model and an intraoral scanner and the crowns were designed with CAD software; in total, 22 crowns were produced. After superimposing CAD design data and scan data using a 3D program, quantitative and qualitative data were obtained for analysis of trueness and precision. Statistical analysis was performed using normality test combined with Levene test for equal variance analysis and independent sample t-test. Type 1 error was set at 0.05. RESULTS. Trueness for the outer and inner surfaces of the SLA crown (SLAC) were $49.6{\pm}9.3{\mu}m$ and $22.5{\pm}5.1{\mu}m$, respectively, and those of the subtractive crown (SUBC) were $31.8{\pm}7.5{\mu}m$ and $14.6{\pm}1.2{\mu}m$, respectively. Precision values for the outer and inner surfaces of the SLAC were $18.7{\pm}6.2{\mu}m$ and $26.9{\pm}8.5{\mu}m$, and those of the SUBC were $25.4{\pm}3.1{\mu}m$ and $13.8{\pm}0.6{\mu}m$, respectively. Trueness values for the outer and inner surfaces of the SLAC and SUBC showed statistically significant differences (P<.001). Precision for the inner surface showed significance (P<.03), whereas that for the outer surface showed no significance (P<.58). CONCLUSION. The study demonstrates that provisional crowns produced by subtractive technology are superior to crowns fabricated by stereolithography in terms of accuracy.

• Journal of Oral Medicine and Pain
• /
• 제21권2호
• /
• pp.293-304
• /
• 1996

The purpose of this study was to investigate the peak electromyographic activity(EMG) and time intervals in firing sequence of Anterior temporalis(TA) and Masseter(MM) on clenching, the number of tender points in the head and neck muscles, the occlusal contact state on clenching, and their relationship. 78 patients with Temporomandibular Disorders(TMDs) participated and were classified into articular or muscular group by clinical signs and symptoms. BioEMG$\textregistered$ of integrated masticatory function analyzer, Biopak$\textregistered$ system(Bioresearch Inc., USA), was used to measure EMG and related items, and T- Scan$\textregistered$(Tekscan, USA), computerized occlusal analyser, was used to record occlusal contact state on maximum voluntary clenching. EMG and occlusal contact were synchronously recorded and analysed with SAS Statistical program. The results of this study were as follows : 1. In total subjects, EMG of TA was lower than that of MM in articular group but in muscular group, vice versa, As a result, the ratio TA to MM was significantly different between the two groups. no significant differece. 3. The number and force of occlusal contact were more in articular group, but there was no significant difference in Total Left-Right statistics(TLR) between the two groups. 4. In unilaterally affected subjects for muscle function, no significant difference was observed between the affected side and the contralateral side in articular group, but in muscular group, the item of the number of tender points showed significant difference. However, for occlusal contact items, contact force in articular group shows significant difference between the two sides. 5. Rate of coincidence of the first firing side of TA with affected side or preferred chewing side was higher and not different between the two groups, but no significant correlation was showed between the first firing side and the first occlusal contact side.

• Journal of Oral Medicine and Pain
• /
• 제19권1호
• /
• pp.137-149
• /
• 1994

This study was performed to investigate the relationship between Forward Head Posture(FHP) and Craniomandlbular Disorders(CMDs). Many studies reported that there was some relationship between them, however, there is still controversy. So It Is necessary to observe and compare many more patients with CMDs wirh normal controls. For the study 85 patients with CMDs and 37 dental students were selected as experimentals and controls, respectively. And the experimentals were classified Into two groups, that is, TMJ internal derangement group and muscle disorders group according to clinical diagnosis. For measuring the FHP, CROM(Cervical-Range-of-Notion)was used. This goniometer is composed of three part. First, gravity goniometer for flexion and extension. Second, magnetic compass and yoke for rotational movement. And last, forward head arm and vertebra locator for forward head posture. Next T-Scan, electronic occlusal analyzer, was used for recording of occlusal contact state. Other items such as maximum opening, lateral excursion, Helkimo's anamnestic index, and muscle palpation point from Friction's craniomandibular index were checked clinically by one examiner. The result of this study were as follows : 1. In male, control group showed much more measurement in resting forward head posture than did experimental group. But there were not significant differences between groups in female subject. From this results, the author contended that CROM is new measuring system and differ from other goniometers in some aspect, so that results should be re-evaluated 2. Mean value of maximum mouth opening in nearly all groups were greater than 40mm. and mouth opening had a significant correlation with occlusal force and with anamnestic index both sex. 3. Mean value of palpation point had not any correlationship with forward head posture in both sex, but there was significant difference between upper and lower group by rounded shouldes. 4. In summary, there was no significant relationship between forward head posture and sign and symptom of Craniomandibular Disorders.