James G. Kereiakes

Relation between Effective Radiation Dose and Outcome of Radioiodine Therapy for Thyroid Cancer

We used a combination of radioiodine scanning and quantitative radiation dosimetry to evaluate responses to therapeutic irradiation with 131I in 76 patients with thyroid adenocarcinoma. Fifty patients received 131I treatment for ablation of residual thyroid tissue after surgical thyroidectomy, and 26 had 131I treatment for metastatic thyroid cancer. Successful ablation was observed in patients receiving higher radiation doses to the thyroid--about 4.4 times those in patients whose lesions were not ablated--largely because of a longer effective half-life of 131I in residual thyroid tissue in the patients with ablated lesions. Patients with metastases that persisted after 131I therapy tended to have more advanced disease and received significantly lower radiation doses per millicurie of administered 131I than did persons whose lesions responded to treatment. Initial 131I treatment resulting in radiation doses of at least 30,000 rad to thyroid remnants and 8000 rad to metastases was associated with a significant increase in the rate of response to therapy.

Ionizing irradiation and the induction of clinically significant disease in the human thyroid gland

Because of increasing concern over continuing medical and potential nonmedical exposure of the thyroid to radiation, risk estimates have been developed for acute thyroiditis, hypothyroidism, and both benign and malignant thyroid nodules following exposure of the human thyroid to external and internal sources of ionizing radiation. These estimates are unique in that they are based entirely on data in human subjects are included corrections for the spontaneous occurrence of thyroid disease in human populations not subjected to radiation whenever possible.

Quantitative External Counting Techniques Enabling Improved Diagnostic and Therapeutic Decisions in Patients with Well-Differentiated Thyroid Cancer

A quantitative technique is described which allows the physician to predict more accurately whether a recurrent or metastatic well-differentiated thyroid carcinoma is amenable to radioiodine-131 therapy or is better treated by other means. A calibrated uptake probe and scaler system is used to obtain conjugate view (i.e., diametrically opposed) counting rates for both the whole body and for any areas of abnormal uptake (lesion) at 24,48 annd 72 hours following the administration of 2 mCi 131l. Quantitative calculations accounting for patient attenuation, lesion size and geometrical factors then provide a determination of the lesion uptake as well as the effective half-life of 131l in the lesion. The radiation dose which would be delivered to the lesion by a given therapeutic amount of 131l may then be calculated to help determine the desirability of 131l treatment. The results of patient studies indicate the potential benefit of such quantitative evaluation.

Experimental studies on the radiation‐modifying effect of cis‐diamminedichloroplatinum II (DDP) in human bladder transitional cell carcinomas grown in nude mice

The effect of cis‐diamminedichloroplatinum II (DDP) and ionizing radiation on human bladder transitional cell carcinoma (TCC) was evaluated in nude mouse‐grown human tumors following administration of single‐agent and combination treatment. Combination of DDP and radiation resulted in accelerated tumor regression and substantially delayed tumor regrowth. The potentiating effect of DDP on ionizing radiation was related to timing and sequence of treatments and was independent of tumor sensitivity to DDP. Best results, as judged by tumor growth curve characteristics, histopathologic changes, and absence of tumor metastases, were obtained when DDP was administered at an early stage following radiation treatment.

The distribution of power and heat produced by interstitial microwave antenna arrays: II. The role of antenna spacing and insertion depth☆

The distribution of power and temperature generated by 915 MHz interstitial microwave antenna arrays was studied in static muscle-equivalent phantoms and both perfused and non-perfused canine thigh muscle. These arrays, which would form the geometric basis of larger volume implants, consisted of four parallel antennas oriented such that transverse to their long axes they formed the corners of a square. Arrays with 2 and 3 cm sides were compared at various depths of insertion where the nodes for all four antennas were coincident at the same depth. The position relative to the antenna nodes of the maximum power and highest temperature within the array volume varied with the depth of insertion of the antennas. Though power dropped rapidly distal to the nodes at all depths, a shift in the location of the maximum power proximal to the nodes resulted in an increase in the effective heating volume at certain insertion depths. For 2 cm array spacing the highest power and temperature were measured along the central axis of the array at all insertion depths. However, arrays using 3 cm spacing generated their maximum power adjacent to the antennas with only 50% of this level occurring along the central axis. When the temperature produced by 3 cm arrays was measured in phantoms midway through simulated 30-minute hyperthermia treatments, the effect of thermal conduction on the temperature distribution was evident. Though power was only 50% centrally, the highest temperatures occurred there. This same pattern of central heating occurred in perfused canine muscle demonstrating the importance of conductive and convective heat redistribution in reducing thermal gradients within the array volume.

Liver size determination in pediatrics using sonographic and scintigraphic techniques

Knowledge of the normal liver size is essential for making the scintigraphic estimate of hepatomegaly. A nomogram for sonographic liver size versus height of the patient was developed for the normal pediatric patient. Liver size was measured as the longitudinal liver length in the plane midway between the xiphoid and the right lateral liver margin. Scintigraphic and sonographic measurements showed a good correlation. The scintigraphic nomogram was developed using the experimentally determined relationship between the two modalities.

Radiation-Induced Change in Serum and Urinary Amylase Levels in Man

Serum and urinary amylase levels in cancer patients were studied before and after radiation treatment. Fourteen patients received radiation to the whole body, 2 to the upper body (above the xiphoid...

Radiation-Associated Carcinoma of the Salivary Glands a Controlled Study

Five hundred fifty-four persons were evaluated who had received external radiation therapy for benign diseases of the head and neck in childhood and whose salivary glands were presumably included in the radiation field. A significant excess of salivary gland cancers were noted when they were compared to 958 nonirradiated control subjects.

RADIATION EXPOSURE FROM RADIOIODINE COMPOUNDS IN PEDIATRICS.

The increasing use of radionuclides in diagnostic procedures and the importance of minimizing radiation exposure to infants and children necessitate accurate and detailed information concerning the doses sustained during these procedures. Although abundant data are available for dosages to adults (1.1, 35, 36) only an occasional reference is found to those received by children of various ages (12). Furthermore, much of the available information deals with exposure to the in-organic form of the radionuclide, while today many of the administered radionuclides are “tagged” to various organic molecules. Since these tagged substances are not handled by the body in the same manner as the inorganic compound, greater or less radiation exposure may result. This situation is particularly pertinent in the case of radioiodine which, because of its abundance, ease of detection, and chemical properties, has been incorporated as a tag for many organic compounds. Table III records the average whole-body radiation doses r...

The Use of Photogrammetry in Tissue Compensator Design

The surface topography of a patient can be determined by photogrammetry before beginning radiotherapy. The source light of the therapy unit or simulator is used to project a grid pattern onto the patient, and this is then photographed together with control points consisting of miniature light bulbs mounted on a frame suspended from the wedge slot of the therapy machine. When the photograph is projected onto a graphics terminal for data entry into a computer, the three-dimensional topography of the patients surface can be reconstructed as a two-dimensional matrix of discrete points. A computer algorithm can then design a tissue compensator to fit the individual patient.