• Journal of Radiation Protection and Research
• /
• v.46 no.4
• /
• pp.151-159
• /
• 2021

Background: Computed tomography (CT) is one of the crucial diagnostic tools in modern medicine. However, careful monitoring of radiation dose for CT patients is essential since the procedure involves ionizing radiation, a known carcinogen. Materials and Methods: The most desirable CT dose descriptor for risk analysis is the organ absorbed dose. A variety of CT organ dose calculators currently available were reviewed in this article. Results and Discussion: Key common elements included in CT dose calculators were discussed and compared, such as computational human phantoms, CT scanner models, organ dose database, effective dose calculation methods, tube current modulation modeling, and user interface platforms. Conclusion: It is envisioned that more research needs to be conducted to more accurately map CT coverage on computational human phantoms, to automatically segment organs and tissues for patient-specific dose calculations, and to accurately estimate radiation dose in the cone beam computed tomography process during image-guided radiation therapy.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.22 no.4
• /
• pp.315-321
• /
• 2022

Although rare, hypodermic needle fractures can occur in the maxillofacial region. In cases of fracture, urgent intervention is required to prevent further complications. We present the case of a 37-year-old female patient with a fractured needle in the left sublingual fossa during a lingual nerve block 6 months before referral. The fragment of a 30-gauge needle was located using cone-beam computed tomography and retrieved under local anesthesia with blunt dissection. The patient recovered uneventfully, except for predictable postoperative inflammatory complications, which resolved within 2 weeks. Precautions should be implemented to prevent needle fractures, which are usually preventable. However, if the retrieval is unsuccessful, the patient should be referred to a well-equipped surgical unit without delay.

• Journal of Korean Dental Science
• /
• v.15 no.2
• /
• pp.147-151
• /
• 2022

Horizontal root fracture (HRF) is a result of trauma to teeth and periodontium, which implies severe injury to cementum, dentin, and pulp. This is a rare case of HRF in the maxillary lateral incisor of a 62-year-old male who only presented persistent gingival swelling, fistula, and dull pain at first. An apical radiolucency of unknown origin turned out to be a result of hidden HRF at the coronal third level that was later visualized radiographically during endodontic treatment. The tooth was scheduled to be extracted upon the patient's agreement. The purpose of this report is to alert clinicians about the importance of diagnosing HRF through thorough clinical and radiographic examinations. Where there is persistent fistula without proper cause, HRF should be considered as a causative factor, and the diagnosis could be effective with aid of cone beam computed tomography, electronic root apex locator, as well as other clinical signs.

• Imaging Science in Dentistry
• /
• v.53 no.1
• /
• pp.35-42
• /
• 2023

Purpose: This study investigated the current dental radiology reporting methods and the recording rate of 10 mandatory reporting items in Korea. Materials and Methods: An original online survey created using Google Forms was distributed to dental practitioners. The survey asked about the participants' age, experience, workplace, use of radiologic equipment, radiology reporting methods, and recording reporting items. Results: In total, 354 responses were analyzed. Radiologic reporting in dental charts was the most commonly used method for each modality. Four out of 10 mandatory items were recorded at a high rate, but the remaining 6 items had substantially lower recording rates, often below 50%. The participants who reported radiographic findings through other separate methods had higher item scores than those who wrote findings in dental charts(P<0.05). Conclusion: Radiologic societies and dental associations should encourage the use of separate reports for radiographic examinations. Education regarding radiology reports and the justification for reporting items should be reinforced in dental schools, training courses on radiology, and the continuing education curriculum.

• Imaging Science in Dentistry
• /
• v.53 no.2
• /
• pp.169-174
• /
• 2023

Gardner syndrome has head and neck manifestations that may be recognized during dental visits. Features such as multiple gnathic osteomas, impacted supernumerary teeth, and multiple foci of idiopathic osteosclerosis can be easily identified on dental radiographs, prompting the clinician to refer the patient for further investigation. A dental examination and routine radiographs play a vital role in revealing the extracolonic presentation of Gardner syndrome, which facilitates timely screening and detection of colorectal cancer and other malignancies associated with this condition. This report discusses the case of a 50-year-old Caucasian man who presented with a hard swelling of the left angle of the mandible and was diagnosed with Gardner syndrome based on abnormal findings from an oral examination, dental imaging, and medical and family history.

• Restorative Dentistry and Endodontics
• /
• v.46 no.4
• /
• pp.50.1-50.8
• /
• 2021

Although several techniques have been proposed to remove fiber-reinforced composite (FRC) post, no safe and efficient technique has been established. Recently, a guided endodontics technique has been introduced in cases of pulp canal obliteration. This study describes 2 cases of FRC post removal from maxillary anterior teeth using this guided endodontics technique with a dental operating microscope. Optically scanned data set from plaster cast model was superimposed with the data set of cone-beam computed tomography. By implant planning software, the path of a guide drill was selected. Based on them, a customized stent was fabricated and utilized to remove the FRC post. Employing guided endodontics, the FRC post was removed quickly and safely with minimizing the loss of the remaining tooth structure. The guided endodontics was a useful option for FRC post removal.

• Imaging Science in Dentistry
• /
• v.53 no.4
• /
• pp.383-388
• /
• 2023

Simple bone cyst is a pseudocyst that typically occurs in patients during their second and third decades of life. This benign entity is an empty or fluid-filled cavity that lacks a true epithelial lining. Simple bone cysts are often asymptomatic and are commonly found in mandibular body, predominantly in the posterior region. The treatment of simple bone cysts can be influenced by factors such as the patient's age, the size of the lesion, and the presence or absence of symptoms. In the case of a simple bone cyst in the mandible that is small and symptomless, a watchful waiting approach may be appropriate. However, if the cyst is large and symptomatic, surgical treatment is recommended. This report presents a radiological examination of a simple bone cyst that developed around the root of the mandibular first molar in a 36-year-old female patient. The cyst recurred in adjacent areas despite surgical treatment.

• Journal of Korean Dental Science
• /
• v.17 no.3
• /
• pp.138-144
• /
• 2024

Osteochondroma, the most common benign bone tumor, rarely occurs in the craniofacial region. This case report presents a sporadic osteochondroma found in the posterior mandibular ramus of a 56-year-old woman, resulting in chronic restricted mouth opening and facial asymmetry persisted over 20 years. Clinical and radiographic examinations, including panoramic and cone-beam computed tomography, revealed a large radiopaque mass causing mechanical locking. Surgical excision of the mass resolved the symptoms without recurrence for 5.5 years. This case underscores the importance of considering osteochondromas in the differential diagnosis of temporomandibular disorders with restricted mouth opening. It emphasizes the necessity for thorough clinical evaluation and careful radiographic interpretation of extraoral findings.

• Korean Journal of Optics and Photonics
• /
• v.25 no.4
• /
• pp.200-206
• /
• 2014

In this paper, using the value theoretically calculated to emit multidirectionally a beam coming into an optical fiber with diameter of $125{\mu}m$, we modeled and produced a cone-shaped structure at the distal end of the fiber. A numerical simulation was performed for an optical fiber tip in which all incident beams were totally reflected and emitted toward the side, as well as for an optical fiber tip from which the beams could be emitted forward and sideways simultaneously. We produced multidirectional-firing optical fiber tips based on the simulation result and model. Laser fabrication of the optical fiber was done by processing a cone-shaped structure at the distal end of an optical fiber with diameter of $125{\mu}m$ using a femtosecond pulsed laser and polishing the processed surface with a $CO_2$ laser. We also conducted an analysis to compare experimental and simulation results.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.2
• /
• pp.289-295
• /
• 2014

Purpose : Cone Beam Computed Tomography(CBCT) in Image Guided Radiation Therapy(IGRT), Set-up error can be reduced but exposure dose of the patient due to CBCT will increase. Through this study, we are to evaluate by making a scenario with the implementation period of CBCT as every other day. Materials and Methods : Of prostate cancer patients, 9 patients who got a Intensity Modulated Radiation Therapy(IMRT) with CBCT in IGRT were analyzed. Based on values corrected by analyzing set-up error by using CBCT every day during actual treatment, we created a scenario that conducts CBCT every other day. After applying set-up error values of the day not performing CBCT in the scenario to the treatment planning system(Pinnacle 9.2, Philips, USA) by moving them from the treatment iso-center during actual treatment, we established re-treatment plan under the same conditions as actual treatment. Based on this, the dose distribution of normal organs and Planning Target Volume(PTV) was compared and analyzed. Results : In the scenario that performs CBCT every other day based on set-up error values when conducting CBCT every day, average X-axis : $0.2{\pm}0.73mm$, Y-axis : $0.1{\pm}0.58mm$, Z-axis : $-1.3{\pm}1.17mm$ difference was shown. This was applied to the treatment planning to establish re-treatment plan and dose distribution was evaluated and as a result, Dmean : -0.17 Gy, D99% : -0.71 Gy of PTV difference was shown in comparison with the result obtained when carrying out CBCT every day. As for normal organs, V66 : 1.55% of rectal wall, V66 : -0.76% of bladder difference was shown. Conclusion : In case of a CBCT perform every other day could reduce exposure dose and additional treatment time. And it is thought to be able to consider the application depending on the condition of the patient because the difference in the dose distribution of normal organs, PTV is not large.