• Applied Microscopy
• /
• v.24 no.1
• /
• pp.28-40
• /
• 1994

Xerostomia and xerophthalmia are delicate or serous side effects, occuring when the radiotherapy is administered to the head and neck cancer patient. It is known that the cause of the above side effect is radiosensitivity of serous cells. In this study, the ultrastructural features of the parotid glands of the X-irradiated rats were observed. Sprague-Dawley rats weighing 200-250g each were anesthetized with sodium thiopental, and placed on the Mitsubishi linear accelerator. Only the head and neck areas of animals were exposured at the distance of 80cm, within the area of $30X30cm$, in the depth of 1cm, with the speed of 200R/min. Total doses applied were 3,000R or 6,000R depending on the experimental groups. Animals were sacrificed on the 6th hour, 2nd day and 6th day after the irradiation. Parotid glands were fixed in the 2.5% glutaraldehyde-1.5% paraformaldehyde solution, and followed by refixation in the 1% osmium tetroxide solution. Dehydrated blocks were embedded in araldite mixture, and ultrathin sections were cut. Sections were contrasted with the solution of uranyl acetate and lead citrate, and observed with JEM 100 CX-II electron microscope. The results were as follows: 1. Normal parotid acinar cells are two types; the light and the dark acinar cells. The light acinar cell contains dense secretory granules, whereas dark acinar cells contains granules of medium density with some darker spots within them, or other cells contain granules of medium density with darker rims. 2. Six hours after the irradiation, many acinar cells were degenerated showing variable stages of cytolytic bodies, light bodies, or dense degenerations. Within the acinar cell, Golgi apparatus and granular endoplasmic reticula were most severely altered elements. Granules showed more contrasting densities and irregularities. 3. Two days after the irradiation, some cytolytic bodies, and focal lucent degeneration of cytoplasm, and fine granular alteration of cytoplasmic matrix were pronounced. But other elements including secretory granules are rather looked unlatered. 4. Six days after the irradiation, most severe alterations were seen. Many intracellular canaliculi (or secretion figures), quanta of cytoplasm containing secretion antecedants, severely irregular luminal border, and again contrasting density of secretory granules showing tigroid spots or dense rims were noted. And myoepithelial degenerations were observed not uncommonly. 5. Irregular densities of secretory granules were interpreted as abnormal components of protein or carbohydrate portion are synthesized or abnormally metabolized under severe X-irradiation. 6. Myoepithelial degeneration and related alteration of nerve endings, etc., were suggested as the other causes of xerostomia following X-irradiation. 7. It is requested that radiation doses should be arranged, considering in mind not only the sensitivity of acinar cells but also the myoepithelial and neural functions.

• Journal of Radiation Protection and Research
• /
• v.36 no.3
• /
• pp.160-167
• /
• 2011

This study conducts cross-comparison through verification of treatment planning of using beam spoiler and bolus, according to the dose variation of different tumor bed and metastatic lymph node cancers, against ionization and optically stimulated luminescence detectors(OSLDs), in head and neck radiotherapy. Verification of treatment planning examined the feasibility of inserting detectors through simulated solid dry water slabs under identical irradiated conditions from treatment planning system to measure beam spoiler and 0.5, 1 cm bolus. In addition, two detectors were cross-compared for verification of treatment planning accuracy and reliability within ${\pm}$2%. The study found that, given a beam spoiler thickness of 0.5 cm and beam spoiler-to-skin distance of 10 cm subjected to optimal dose distribution given for metastatic lymph node cancers, the bolus low-level skin dose was less, and the tumor bed dose reduced slightly. Additionally, two detectors were cross-compared for accuracy within ${\pm}$1%. Accordingly, The use of beam spoiler was determined that reduces skin side effects and can deliver an optimal dose distribution for tumor, and to apply to future clinical studies should be performed.

• Radiation Oncology Journal
• /
• v.5 no.2
• /
• pp.149-155
• /
• 1987

The success of radioation therapy depends on exact treatment of the tumor with significant high dose for maximizing local control and excluding the normal tissues for minimizing unwanted complications. To achieve these goals, correct estimation of target volume in three dimension, exact dose distribution in tumor and normal critical structures and correction of tissue inhomogeneity are required. The effect of therapy oriented CT (plannng CT) were compared with conventional simulation method in necessity of planning change, set dose, and proper distribution of tumor dose. Of 365 new patients examined, planning CT was performed in 104 patients $(28\%)$. Treatment planning was changed in $47\%$ of head and neck tumor, $79\%$ of intrathoracic tumor and $63\%$ of abdmonial tumor. in breast cancer and musculoskeletal tumors, planning CT was recommended for selection of adequate energy and calculation of exact dose to critical structures such as kidney or spinal cord. The average difference of tumor doses between CT planning and conventional simulation was $10\%$ in intrathoracic and intra-abdominal tumors but $20\%$ in head and neck tumors which suggested that tumor dose may be overestimated in conventional simulation Although some limitations and disadvantages including the cost and irradiation during CT are still criticizing, our study showed that CT Planning is very helpful in radiotherapy Planning.

• Korean Journal of Head & Neck Oncology
• /
• v.19 no.2
• /
• pp.127-132
• /
• 2003

Objectives: The best treatment for the malignant parotid tumor still remains to be defined, and a better knowledge about the tumor features that predict the treatment result is needed. The aim of this study is to evaluate the treatment outcomes and to suggest the optimal treatment modality for the parotid cancer. Materials and Methods: The clinicopathologic characteristics of 113 patients who were treated for parotid cancer from January 1990 to December 2002 were retrospectively analysed. Univalate analyses were performed to establish the prognostic influence of pateint age, gender, tumor size, histologic grade and lymph node metastasis. Results: The mean age was 46.4 years old (15-81 years) and. The male to female ratio was 1 : 1.1. The chief complaint was a palpable mass in 85%, pain was in 12.4% and facial nerve palsy was accompanied with 2.7%. The mean tumor size was 3.5cm in diameter. The most common malignant tumor was mucoepidermoid carcinoma (33.6%), followed by acinic cell carcinoma (15%), adenoid cystic carcinoma (11%), carcinoma expleomorhpic adenoma (11%), basal cell carcinoma (7%). The most common operative procedure was total parotidectomy (47.8%) and various types of cervical lymph node dissection were added in 69.9%. Postoperative radiotherapy was done in 61.1 %. Postoperative complications developed in 54 cases (47.8%), including 46 cases (40.7%) of facial nerve palsy and 9 cases (8%) of Frey's syndrome. Recurrences developed in 21 cases (18.6%) and deaths in 15 (13.3%). Cumulative survival at 5 year was 75.4%. Univariate analysis of clinical factors showed that histologic grade and positive cervical lymph node significantly influenced survival (p<0.05). Conclusion: These results suggests that the radical resection with lymph node dissection and postopertaive XRT would be necessary to improve the survival of the patients with high grade cancer or positive lymphnode metastasis.

• Korean Journal of Head & Neck Oncology
• /
• v.24 no.1
• /
• pp.26-32
• /
• 2008

Purpose：Hypopharyngeal carcinoma is usually diagnosed as an advanced disease after an asymptomatic beginning, and it is related to a high frequency of lymph node metastases. An eventual negative outcome may occur not only because of possible locoregional failures but also for frequent distant metastases. Thus, the efficacy of induction chemotherapy followed by radiation therapy, with regards to the response, survival rate and complications for locally advanced hypopharyngeal carcinoma patients, was examined. Methods and Materials：Since July 1998 to February 2001, 18 patients having locally advanced hypopharyngeal carcinoma were treated with induction chemotherapy followed by radiation therapy, and the results were retrospectively analyzed. The regimen of the induction chemotherapy was the 5-flurouracil(5-FU, 1,000mg/$m^2$ daily for 5 consecutive days) and cisplatin(100mg/$m^2$ on day 1) combination at 3-week intervals for 2 cycles. The total radiation dose for the primary tumor and metastatic lymph nodes was 68.4-72.0Gy(median：70.2Gy) Results：The 3-year overall survival rate and disease free survival rate were 31.3% and 22.2%, respectively. In 6 patients(33.3%), preservation of the larynx for over 3 years was possible. After the induction chemotherapy and radiotherapy, a complete response was noted in 14 patients(77.8%), and a partial response in 4 patients (22.2%), with an overall response rate of 100%. Conclusion：Induction chemotherapy followed by radiation therapy is an effective treatment and larynx preservation rate was 33% in patients with locally advanced hypopharyngeal carcinoma in our report.

• Korean Journal of Head & Neck Oncology
• /
• v.26 no.2
• /
• pp.171-177
• /
• 2010

연구목적 : 비인두암 환자들을 대상으로 방사선치료 시 삼차원입체조형치료기법과 용적세기조절회전치료기법을 비교하고 이하선을 포함한 정상조직 보호에 있어 그 차이점을 알아 보고자 본 연구를 시행하였다. 대상 및 방법 : 비인두암 환자 5명을 대상으로 치료계획용 CT(computed tomography)를 시행 후 삼차원입체조형방사선치료계획 과 용적세기조절회전치료계획을 시행하였다. 이를 바탕으로 얻은 선량분포, conformity index(CI) 그리고 선량체적 히스토그램을 통해 손상위험장기(organ at risk)와 계획용표적체적(planning target volume)을 비교 분석하였다. 결 과 : 분석결과 이하선에 조사되는 평균선량이 용적세기조절회전치료계획에서는 43.9%로 삼차원입체조형치료계획에서의 89.4% 보다 유의하게(p=0.043) 감소하였다. 계획용표적체적 conformity index의 경우 용적세기조절회전치료계획 (CI=1.06)에서 삼차원입체조형치료계획(CI=2.55) 보다 유의하게(p=0.043) 향상된 결과를 보였다. 결 론 : 비인두암 환자에서 용적세기조절회전 치료계획 시 삼차원입체조형치료계획 보다 유의하게 이하선에 평균선량이 줄었고 계획용 표적체적에 대한 conformity도 유의하게 향상되는 결과를 보였다. 본 연구가 적은 수의 환자를 대상으로 하였으나 용적세기조절회전치료기법을 시행 시 구강건조증의 발생을 줄일 수 있을 것으로 기대된다. 향후 더 많은 환자군을 대상으로 한 임상연구가 필요할 것으로 사료된다.

• Korean Journal of Head & Neck Oncology
• /
• v.19 no.1
• /
• pp.34-40
• /
• 2003

Objective: To analyze the treatment-related parameters after the radiotherapy of T1N0 squamous cell carcinoma of the glottic larynx. Materials and Methods: Between October 1989 and August 2000, 54 patients with histologically proven T1N0 squamous cell carcinoma of the glottic larynx who received definitive radiation therapy in Department of Radiation Oncology, Asan Medical Center were analyzed. They were all males with age ranged from 31 to 80 years (median 61 years). 1997 AJCC stages were 31 T1a, 23 T1b. Patients were treated with 4-MV X-rays with a parallel-opposed two-field technique. Ten patients received 66.0-68.4Gy at 1.2Gy per fraction twice daily, 21 patients received 64.8-66.6Gy at 1.8Gy per fraction once daily, and 23 patients received 66.0Gy at 2.0Gy per fraction once daily. Follow-up period was 16-119 months (median 56 months). Results: 5-year overall survival and local control rates for patients with T1 lesions were 87.0% and 88.5%, respectively. 5-year local control with larynx preservation rate was 90.5%. Host and tumor-related prognostic factors including age, stage, anterior commissure involvement and tumor bulk proved not to be significant. Only shorter overall treatment time among treatment-related factors had correlation with imporved local control. Conclusion: Comparable high local control rate with organ preservation was achieved with primary radiation therapy and salvage surgery. Shortening of overall treatment time is related to improved local control rate. To determine the optimal fractionation scheme, randomized trial is mandatory.

• Korean Journal of Head & Neck Oncology
• /
• v.16 no.2
• /
• pp.167-171
• /
• 2000

Objectives: To compare the outcomes of treatment with a focus on the effectiveness of the two primary techniques of radiation used for treating parotid gland malignancies. Materials and Methods: A retrospective analysis of 70 patients with parotid gland cancer treated between 1981-1997. Radiation was delivered through an ipsilateral field of high energy electron and photon in 37 patients(52.9%). Two wedge paired photon was used to treat in 33 patients(47.1%). The median dose was 60 Gy, typically delivered at 1.8-2.0Gy per fraction. The median follow-up times for surviving patients was 60 months. Results: The overall and disease free 5 year survival rates were 71.6% and 69.5%, respectively. Wedge paired photon and photon-electron treatment disease tree 5 year survival rates were 61.1% and 80.5%, respectively. Overall local failure rate was 18.6%. Local failure rate of wedge paired photon technique was higher than that of mixed beam technique. Late complication rate was 37.1%, but most of them were mild grade. Conclusion: Techniques of radiation were associated with local control. The technique of using an ipsilateral field encompassing the parotid bed and treated with high energy electrons often mixed photons was effective with minimal severe late toxicity. To irradiate deep sited tumors, we consider 3-D conformal treatment plan for well encompassing the target volume.

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

• The Journal of Korean Society for Radiation Therapy
• /
• v.16 no.1
• /
• pp.91-99
• /
• 2004

Purpose : For the head and neck radiotherapy, abutting photon field with electron field is frequently used for the irradiation of posterior neck when tolerable dose on spinal cord has been reached. Materials and methods : Using 6 MV X-ray and 9 MeV electron beams of Clinac1800(Varian, USA) linear accelerator, we performed film dosimetry by the X-OMAT V film of Kodak in solid water phantom according to depths(0 cm, 1.5 cm, 3 cm, 5 cm). 6 MV X-ray and 9 MeV electron(1Gy) were exposes to 8cm depth and surface(SSD 100cm) of phantom. The dose distribution to the junction line between photon($10cm{\times}10cm$ field with block) and electron($15cm{\times}15cm$ field with block) fields was also measured according to depths(0 cm, 0.5 1.5 cm, 3 cm, 5 cm). Results : At the junction line between photon and electron fields, the hot spot was developed on the side of the photon field and a cold spot was developed on that of the electron field. The hot spot in the photon side was developed at depth 1.5 cm with 7 mm width. The maximum dose of hot spot was increased to $6\%$ of reference doses in the photon field. The cold spot in the electron side was developed at all measured depths(0.5 cm-3 cm) with 1-12.5 mm widths. The decreased dose in the cold spot was $4.5-30\%$ of reference dose in the electron field. Conclusion : When we make use of abutting photon field with electron field for the treatment of head and neck cancer we should consider the hot and cold dose area in the junction of photon and electron field according to location of tumor.