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Biomedical subjects

C C Ling

Publications and source records attributed to C C Ling.

At least 145 records · Page 8Linked to original sources
PubMed1983

Directional dependence of radiation fluence from 192Ir and 198Au sources.

Radiation fluence distribution around 192Ir and 198Au seeds of the type used for brachytherapy application was measured using a NaI crystal connected to a multi-channel analyzer. The radiation fluence, determined as a function of the angle between the seed axis and the direction of detection, is anisotropic with the fluence along the seed axis amounting to 78% of that perpendicular to the seed axis for seeds of both isotopes. The region of fluence reduction is broader for 198Au seeds, extending from 0-45 degrees; for 192Ir the decrease in fluence is evident for angles of 0-20 degrees. Integration of the angular distribution over 4 pi geometry indicated the effective activity of the implants to be 4% and 1% less than the nominal activity for the 198Au and 192Ir seeds, respectively, based on calibration measurements perpendicular to the seed axis.

Brachytherapy↗
PubMed1980

Iodine-125 implant and external beam irradiation in patients with localized pancreatic carcinoma: a comparative study to surgical resection.

Twelve patients with biopsy-proven clinically localized ductal pancreatic cancers (less than 7 cm in greatest diameter) judged unsuitable for resection were treated by bypass surgery, an Iodine-125 implant (20-39 mCi), and postoperative irradiation (4000-4500 rads). The potential problems of significant bleeding, pancreatic fistula, or pancreatitis were not experienced. A local recurrence developed in one patient and two recurred in regional lymph nodes. The projected median survival of the group is 11 months with four of the 12 patients still surviving. For purposes of comparison all patients with pancreatic ductal carcinoma treated by radical resection during a similar time were evaluated. All ten have died with a median survival of six months. Twelve of 22 (55%) of the combined implanted and resected groups have developed distant metastasis. Further pursuit of intraoperative techniques of irradiation in combination with adjuvant multidrug chemotherapy seems indicated in an attempt to prolong patient survival which is now limited by hematogenous metastases.

Adult↗
PubMed1980

Preoperative irradiation, lymphadenectomy and 125iodine implant for patients with localized prostatic carcinoma: a correlation of implant dosimetry with clinical results.

The 30 patients with clinically and surgically localized prostatic carcinoma who were selected for treatment by a short course of preoperative irradiation (1,050 rad), pelvic lymphadenectomy and 125iodine implant have been followed for 1 to 4 years. Perioperative morbidity (10 per cent), postimplant impotence (11 per cent), lymphedema (17 per cent), tumor recurrence (4 per cent) and distant metastasis (4 per cent) have been minimal to date. However, urinary irritative symptoms, which usually subsided in 6 to 9 months, occurred in half of the patients and correlated with implant volume. Total dose and total dose per unit of implanted activity were calculated. Of the various implant parameters evaluated implant dose homogeneity has corrrelated with the rate of tumor regression.

Brachytherapy↗
PubMed1976

Irradiation of cells by single and double pulses of high intensity radiation: oxygen sensitization and diffusion kinetics.

The biological effects of ionizing radiation in living cells are the ultimate result of a long chain of events with the initial step being the local absorption of radiation. Whereas such physical abosrption is probably over within 10(-16) s after dose delivery, the biological consequences of radiation do not manifest themselves until very much later times. Between these two extremes of time, events occur relatively early at the molecular level which are undoubtedly critically related to the still unknown basic mechanisms of cellular radiation damage. These events may include not only the interaction of highly reactive species produced within the cell but also the diffusion of molecules such as oxygen or other chemical radiosensitizers.

Bacteria↗