PubMed Health⌕ Search

Biomedical subjects

F J Lin

Publications and source records attributed to F J Lin.

At least 55 records · Page 3Linked to original sources
PubMed1990

Prognostic factors of nasopharyngeal carcinoma: a multivariate analysis.

Between 1979 and 1985, 561 patients with nasopharyngeal carcinoma were reviewed to determine prognostic factors that may influence survival. Sex (p = 0.294) and histopathology (p = 0.677) had no correlation to the actuarial survival, whereas the site of cervical metastasis (p = 0.001) and the radiation doses to the nasopharynx and regional lymph nodes (p = 0.03) were both significant when one used univariate analyses. Cox's multivariate regression model revealed that the presence rather than the site of distant metastases was the single most important independent factor influencing the treatment outcome (p less than 0.0001). The addition of chemotherapy, on the other hand, did not show a survival benefit even when one took available confounding factors into account. There are, however, survival advantages associated with: (a) young age (less than or equal to 40 years), (b) asymptomatic status, (c) Stage I or II lesions, and (d) biopsy via nasopharynx instead of neck nodes. These favorable prognostic factors may be used for therapeutic guidance and end-result reporting.

Adolescent↗
PubMed1990

[Evaluation of quality assurance program in high dose rate remote after-loading brachytherapy].

In the past 9 years, we have routinely used high-dose-rate remote afterloading systems, a Toshiba RAL-302-2 remote afterloading system and a self-fabricated Ir-192 system, for radiation therapy of various cancers, particularly cancers of the uterine cervix and nasopharynx. The frequency of using these two systems is more than 30 times per week. These machines can deliver high-dose radiation (300-1000 cGy) to a specifically planned target on the patient in a few minutes, therefore, the performance of the systems requires well planned dosimetry and quality control assurance in order to achieve effective therapeutic results and ensure safety of the patient under treatment. Any malfunction of the machines may cause over-radiation that exceeds a planned dose to the patient, and any distortion in the distribution of a planned dose may give an unexpected high dose of radiation to the therapist operating the machines. Hence, a quality assurance program must be enforced regularly to avoid or minimize any possible accidents. Based on information and recommendations reported in the literature, as well as from our own experience, we set up a program of routine checks to correct and adjust the machinery conditions and to ensure the optimum operational status of the equipment on a weekly, monthly, semiannual and annual basis. In checking the Co-60 machine, we found that the rate of occurrence for abnormal source position was 3.9% and that for the timer was 2.8%. In the Ir-192 machine checks, abnormal conditions were found only in the source position at the rate of 7.8%.

Brachytherapy↗
PubMed1990

[Effect of eye shielding block position on dose to lens during radiation therapy].

The lens of the eye is very sensitive to radiation and a low dose of radiation may induce cataracts a few years after radiation therapy. In treatment of head and neck tumors, such as cancer of the ethmoid or maxillary sinus, an adequate eye shielding block is mandatory for reducing the lens dose in order to prevent cataract formation. Experiments were designed to simulate the setup of the lens during radiation therapy and it was observed that the dose to the lens was correlated with the distance between the eye shielding block and the eye surface for Co-60, 10MV and 6MV X-rays. With properly fabricated divergent blocks, the optimal shielding points were found to be 6 cm, 0.9 cm and 1.4 cm above the eye surface for Co-60, 10MV and 6MV X-rays, respectively. In a 10 x 10 cm2 field, by moving the eye shielding block on the blocking tray to the optimal shielding point near the surface, the dose to the lens can be reduced from 14% to 8% for Co-60 beams and from 17% to 7% for 10MV and 6MV X-rays. This effect is more evident in larger field sizes. We recommend that the eye shielding block be placed at the optimal shielding point to minimize the dose to the lens. If the eye shielding block cannot be placed at the optimal shielding point, a simple coin placed on the eye lid surface will also reduce the lens dose substantially when a regular eye shielding block is placed on the blocking tray (Lin's coin effect).

Cataract↗
PubMed1990

[Effect of topical fluoridation on post-radiation caries in patients with head and neck cancer].

Post-radiation caries, a rapidly progressing and highly destructive type of dental caries, is one of the most common post- radiation complications in patients with head and neck cancer. Topical fluoride application has been shown in clinical studies to reduce post-radiation caries in irradiated patients. This study reviewed 148 patients who had received radiation for head and neck cancer. All the subjects received pre-radiation dental care. After radiation, the first group consisted of 53 patients who were under regular 3 months dental recall and received topical fluoride applications. The second group consisted of 95 patients who did not return for regular dental recall. Result from clinical examination and bitewing radiographs revealed that the caries indexes were 7% and 31% for the first and second groups, respectively. Chi-Square test showed significant difference between the two groups (P value less than 0.005). Regular topical fluoride application is valuable in reducing dental caries after radiation for head and neck cancer.

Administration, Topical↗
PubMed1990

Thymic carcinomas: histopathological varieties and immunohistochemical study.

Thirteen cases of primary thymic carcinomas are described. The patients' ages ranged from 19 to 64 years, with a median of 40 years. Nine of them were male. Chest pain with or without cough was the main presenting symptom. No patient had myasthenia gravis. Five histological types were identified; two were undifferentiated (lymphoepithelioma-like) carcinoma, one was a clear-cell carcinoma, two were mixed squamous and small-cell carcinoma, and six were squamous cell carcinoma. All the tumors were variably positive for anti-keratin antibody AE1 and AE3, but negative for AE2. Anti-neuron specific enolase antibody was useful in identifying and confirming the small-cell carcinoma component of the mixed carcinomas. Anti-epithelial membrane antigen antibody aided in revealing the glandular structures in mixed adenosquamous and small-cell carcinomas. Thymic carcinomas were histopathologically differentiated from thymomas by their malignant cytological appearance, increased mitotic activity, and central tumor necrosis. All six patients with pure squamous-cell carcinoma were still alive, with a median survival time of 27 months. All but one of the other patients of different histological types died, the exception being a recent case of mixed adenosquamous and small-cell carcinoma; their median survival was 19.5 months, or 18 months when the latter surviving case is included. The prognosis of patients with pure squamous-cell carcinoma was better.

Adult↗
PubMed1989

[Radiation safety program at the Chang Gung Memorial Hospital].

There are many areas in several departments where radiation-producing facilities are routinely used for diagnosis and therapy in Chang Gung Memorial Hospital. We used RD-8 Wallac survey meters to survey the surroundings of controlled and noncontrolled areas. The results of the survey showed background level in the noncontrolled areas and under 0.2 mR/hr in the controlled areas. In diagnostic fluoroscopy, the worker wore 0.5mm lead apron and received an exposure under 0.5 mR/hr. The operator of the portable X-ray machine was exposed to an exposure of background level when he was 4.5 meter from target and wore a 0.5mm lead apron. The patients in the nuclear medicine department were given 15m Ci Tc-99m for bone scan and the exposure rate was under 0.5 mR/hr at 1.0 meter from the patient. The patient loaded with 55 mCi of Cs-137 for brachytherapy produced exposure rate of 1.5 mR/hr behind lead shielding placed beside the patient bed, and the surroundings outside the room was at background level. We also checked the execution and enforcement of the radiation safety regulations which was found to have met the requirements of the Atomic Energy Council.

Hospital Departments↗
PubMed1989

[Clinical evaluation of aggressive nutritional care to head and neck cancer patients during radiation therapy].

Anorexia, dysphagia, and dysgeusia are the most prevalent symptoms in head and neck cancer patients during radiation therapy. The patients, who were in poor general condition, suffered marked loss of body weight and consequently were unable to tolerate further anti-cancer treatments. Aggressive nutritional support to the head and neck cancer patients was started in April, 1986 to improve the general condition of these patients in our hospital. The physiological condition of 152 patients who underwent nutritional support were evaluated as a study group (Group I) between August 1986 and May 1987. Group II, 165 patients without nutritional care were evaluated as a control group between August 1985 and May 1986. In Group I, oral supplementary diets or enteral feedings were provided as nutritional support to all of the anorectic patients. Anthropometric measurement and laboratory data were collected in both groups at the several time points. An average of 1.1 kilogram (Kg) and 3.5Kg body weight loss was observed in Group I and Group II, respectively (P less than 0.005). In patients diagnosed with nasopharyngeal carcinoma, the average duration of radiation treatment was 11 days shorter in Group I than that in Group II (42 vs 53 days). In conclusion, aggressive nutritional care performed by a group of clinical staff, which included doctors (radiation oncologist), dietitians and oncologic nurses, was sufficient to improve the general condition of the head and neck cancer patients during radiation therapy and to therefore increase the recovery rate of these patients after radiation treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Clinical significance of cranial nerve deficit in the therapy of nasopharyngeal carcinoma.

The results of radiation treatment of nasopharyngeal carcinoma (NPC) have recently been improved, but the prognosis remains relatively poor in cases with cranial nerve (CN) involvement. A total of 109 cases with histologically-proven NPC and cranial nerve involvement treated during 1979-1985 were reviewed and analysed. Definitive radiotherapy (RT) was given to patients with a high upper margin of the RT field at 2.5 cm above the base of the skull to a total dose of 70.2 Gy/39 fractions/8 weeks, with two applications of intranasopharyngeal brachytherapy. There were 37 cases (34%) in Group I (upward invasion only) and 72 cases (66%) in Group II (bidirectional invasion). Abducens, trigeminal, oculomotor and facial were the commonly involved nerves. Headache was the major symptom at diagnosis and was present in 82.6% of the patients, significantly higher than in general NPC cases (p less than 0.005). Fifty per cent (31/62) achieved complete response to definitive RT, but it did not correlate well with survival rate. The residual neurological deficit of each CN ranged from 31 to 57%. The actuarial 5-year survival rates of Groups I and II were similar in spite of neck lymph node metastasis in Group II (33% (I) compared with 24% (II); p greater than 0.05). Cases with single CN deficit did not show better results than those with multiple CN involvements. Five-year survivors were seen only in those who received a complete course of definitive RT.

Adult↗
PubMed1989

[Arterial blood gas changes in patients with malignant airway obstruction treated with Nd-YAG laser under local anesthesia].

The purpose of this report is to observe the changes in arterial blood gas in patients with malignant airway obstruction treated with Nd-YAG laser under local anesthesia. Nine inoperable lung cancers (7 primary, 2 metastatic) with tracheal and/or bronchial obstruction were studied. Recanalization of the obstructing airway was the goal of Nd-YAG laser treatment. Arterial blood gas levels were measured at rest, post-bronchoscopy, during treatment with Nd-YAG laser, immediately after treatment, and at each hour post-treatment for 5 hours. Blood samples were obtained from a cannula that had already been inserted into the radial artery. A significant decrease in PaCO2 levels was noted after bronchoscopy (12.1 +/- 7.47 mmHg, p less than 0.005), during laser phot resection (16.9 +/- 6.37 mmHg, p less than 0.001), immediately (17.7 +/- 8.51 mmHg, p less than 0.001) and at 1 hour (12.4 +/- 14.01 mmHg, p less than 0.05) after the Nd-YAG laser treatment. No significant changes (p greater than 0.05) in PaCO2 levels were found at 2, 3, 4, 5 hours after treatment. Both PaCO2 and PH showed no significant changes during the process. Because of the marked decline in PaCO2 during and after the Nd-YAG laser treatment, it is suggested that oxygen supplementation should be considered, particularly in hypoxemic patients.

Adult↗
PubMed1989

[Prognosis of chronic obstructive pulmonary disease after acute respiratory failure].

We followed the course of 53 patients (male 38, female 15 and average age 66 +/- 10) with chronic obstructive pulmonary disease hospitalized in our intensive care unit due to acute episode of respiratory failure. Etiologies of acute respiratory failure, patient's clinical data and arterial blood gases analysis were recorded. Most of the results showed no significant difference between the initial survival and the non-survival group. Low hematocrit. hypoalbulinemia and severe hypoxemia were found in the dead group but relative hypercapnea in the survival group was noted. Infection was the most common cause of acute respiratory failure and following by congestive heart failure, pneumothorax and asphyxia. Intubation and mechanical ventilator were needed in all patients except 3 cases to whom only conservative treatment was given. Hospital mortality was 50.9 percent (27/53) and most of the cases (22/53) died in the intensive care unit. Twenty six cases (49.1%) were discharged from the hospital and follow-up was continued for at least two years. Fifteen patients died during two year follow-up and except for one suicide case all died of repeated respiratory failure. The two year survival was only 20.8 percent (11/53). The prognosis of patients with chronic obstructive pulmonary disease following an episode of acute respiratory failure is poor.

Acute Disease↗
PubMed1989

Prospective hormone study of hypothalamic-pituitary function in patients with nasopharyngeal carcinoma after high dose irradiation.

With the aim of evaluating the effect of high dose irradiation (6,500 cGy/36 fractions or higher) to pituitary fossa, a prospective study was carried out in patients with nasopharyngeal cancer by a serial determination of several hormones in the serum, before and after the course of radiation therapy (RT). The radiation treatment field was at least 1 cm above the skull base with bilateral parallel opposing fields. Hormone assays were performed three times on each patient: (1) prior to, (2) one month after, (3) 15-18 months after radiation therapy. The study included determination of serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), cortisol, growth hormone (GH) and prolactin concentrations and LH-releasing hormone, thyrotrophin-releasing hormone stimulation and insulin tolerance tests were also carried out. Complete profiles were obtained in 24 patients (16 males and 8 females), aged 16-67 years. The results showed a significant decrease in the level of serum peak value of LH in males 18 months after therapy, and also in GH both one month and 18 months after therapy. A significant increase in the peak value of serum TSH observed after therapy. Decreased serum FSH, cortisol and prolactin levels were noted, but these did not reach statistical significance. The decrease in GH level appeared earlier and was more sensitive than that found for the other hormones, and could prove to be a useful parameter for clinical evaluation. None of the patients showed any clinically recognizable symptoms or signs of hormone deficiency in the 18-33 months following completion of the radiation therapy.

Adolescent↗
PubMed1989

Dosimetry of high dose rate intracavitary radiation therapy using Co-60 and Ir-192 sources.

For decades, the high dose rate sources of Co-60 and Ir-192 have been used in remote controlled afterloading brachytherapy. A small volume ion chamber was used to measure the dose rate in varying distances from the sources. The entire dose distribution around the source was tabulated and the data were used to calculate the treatment time for individualized patient setting. A solid diode detector was used to plot the relative distance dose and the symmetrical dose distribution of the sources. Thermoluminescence dosimetry (TLD) was used for spot-checking of the dose. The dose distribution in the clinically useful range of 2-5 cm was carefully estimated. When normalized at 2.0 cm from the source, the dose rate at 5.0 cm was 17.1% for the Co-60 source and 18.4% for the Ir-192 source. It is clearly demonstrated that Ir-192 offers no dosimetric advantages, which is contrary to what used to be believed by some clinicians. The parameters of the computer treatment planning system have to be corrected and then adopted into clinical application.

Brachytherapy↗
PubMed1989

Determination of possible doses to the gonads or fetus in pregnant patients during radiation therapy.

Some of the women undergoing radiation therapy may be pregnant and the scatter radiation to the fetus and gonads is a matter of great concern. Quantitative measurement of the scatter dose in polystyrene solid phantoms with a Farmer type chamber and effects of shielding blocks under the collimators were studied. The scatter dose outside of the primary beam was found to be decreasing exponentially with increasing distance from the radiation beam edge. When the distance increased from 10 cm to 60 cm, the scatter dose drops from 1-2% to 0.15% for the Co-60 beam and from 1-2% to 0.02% for the 10 MV X-rays. The collimation system was a major source of scatter radiation because the scatter dose could be substantially reduced by placing shielding blocks under the collimators and the scatter dosed varied with field sizes. The lead apron used in diagnostic radiographic procedures reduced the scatter dose by 5-6% only. The scatter dose distribution in the body outside of the radiation field was also analyzed.

Female↗
PubMed1988

[A preliminary study for cellular, albumin and immunoglobulin components of bronchoalveolar lavage fluid in normal control, pulmonary T.B. and malignant lung diseases].

Bronchoalveolar lavage (BAL) is a new diagnostic tool which could be applied repeatedly to investigate the nature of lesion in pulmonary diseases. To evaluate the clinical significance of the difference in immunoglobulin content for the differential diagnosis between benign and malignant pulmonary diseases, we performed bronchoalveolar lavage for 64 patients. They included 12 patients with bronchogenic carcinoma, 12 patients with pulmonary tuberculosis, 20 patients with benign non-specific bronchopulmonary diseases (these including 6 patients with pneumoconiosis, 6 patients with bronchietasis, 2 patients with paraquate intoxication, 6 patients with pneumonia) and 20 healthy persons as of the control group. We analyzed the following items: (1) cell count (2) differential count (3) protein content (4) immunoglobulin content. The results showed that there were increase in PMN cells in paraquate intoxication, pnuenmonia and bronchiectasis. While there was lymphocytosis in pulmonary tuberculosis. In comparison with the control group, there was elevation of statistical significance in the IgA/Albumin ratio in bronchogenic carcinoma and pulmonary tuberculosis. Although the IgG/Albumin ratio would be elevated with statistical significance among a variety of pulmonary diseases, it was particularly high in pulmonary tuberculosis. In contrast, the IgA/IgG ratio was significantly increased only in bronchogenic carcinoma. In conclusion, there were differences in the cell number, differential cell count, protein content and immunoglobulin content among various pulmonary diseases. It may be useful in making differential diagnosis between benign and malignant pulmonary disease and the prediction of prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗