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H R Maxon

Publications and source records attributed to H R Maxon.

At least 19 recordsLinked to original sources
PubMed1992

Rhenium-186 hydroxyethylidene diphosphonate for the treatment of painful osseous metastases.

Rhenium-186 (tin)hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that localizes in skeletal metastases in patients with advanced cancer. A single intravenous administration of approximately 34 mCi (1,258 MBq) resulted in significant improvement in pain in 33 of 43 evaluable patients (77%) following the initial injection, and in 7 of 14 evaluable patients (50%) following a second treatment. Patients responding to treatment experienced an average decrease in pain of about 60%, with one in five treatments resulting in a complete resolution of pain. The only adverse clinical reaction was the occurrence after about 10% of the administered doses of a mild, transient increase in pain within a few days following injection. Statistically significant but clinically unimportant decreases in total white blood cell counts and total platelet counts were observed within the first 8 weeks following the injection; no other toxicity was apparent. Rhenium-186(Sn)HEDP is a useful new compound for the palliation of painful skeletal metastases.

Bone Neoplasms↗
PubMed1992

Safety and efficacy of repeated sequential administrations of Re-186(Sn)HEDP as palliative therapy for painful skeletal metastases. Initial case reports of two patients.

Single intravenous injections of 30 to 35 mCi (1,110 to 1,295 MBq) of Re-186(Sn)HEDP previously have been shown to result in palliation of painful skeletal metastases from prostate cancer. There are no reports of patients receiving repetitive Re-186(Sn)HEDP therapy. We have followed two such patients who received multiple (five to seven) injections of Re-186(Sn)HEDP at 2-month intervals. Each experienced a sustained decrease in both pain and analgesic intake. The only evident clinical or biochemical toxicity was a mild progressive decline in their total platelet counts.

Adenocarcinoma↗
PubMed1992

Radioiodine-131 therapy for well-differentiated thyroid cancer--a quantitative radiation dosimetric approach: outcome and validation in 85 patients.

For almost five decades, 131I treatment of thyroid cancer has been based empirically on administered activity rather than on actual radiation doses delivered. In 1983, we defined radiation dose thresholds for successful treatment. This report is concerned with the subsequent validation of those thresholds in 85 patients. The successful ablation of thyroid remnants occurred after a single initial 131I administration in 84% of inpatients and in 79% of outpatients when treatment was standardized to a radiation dose of at least 30,000 cGy (rad). Administered activities low enough to permit outpatient therapy could be used in 47% of the patients. Lymph node metastases were treated successfully in 74% of patients with a single administration of 131I calculated to deliver at least 8,500 cGy (rad). For athyrotic patients with nodal metastases only, success was achieved in 86% of patients at tumor doses of at least 14,000 cGy (rad). These success rates are equal to or better than those reported with empiric methods of 131I administration. The individualized treatment planning selectively allocates hospitalization and higher exposures to 131I to those patients who require them.

Adenocarcinoma↗
PubMed1991

Rhenium-186(Sn)HEDP for treatment of painful osseous metastases: results of a double-blind crossover comparison with placebo.

Rhenium-186 (tin) hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that simultaneously localizes in multiple skeletal metastases in patients with advanced cancer. A single intravenous administration of 30-35 mCi (1110-1295 MBq) is associated with a prompt, significant relief of osseous pain in about 80% of such patients. The efficacy of this new compound was evaluated further by utilizing a double-blind crossover comparison with 99mTc-methylene diphosphonate (MDP) as a radioactive placebo. The new rhenium compound resulted in a significantly (p less than 0.05) greater decrease in pain than did treatment with the radioactive placebo. Rhenium-186(Sn)HEDP appears to be a useful new compound for the palliation of painful skeletal metastases.

Aged↗
PubMed1990

Re-186(Sn) HEDP for treatment of painful osseous metastases: initial clinical experience in 20 patients with hormone-resistant prostate cancer.

Rhenium-186(tin) hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that localizes in areas of osseous metastases in a manner similar to that of standard bone-scanning agents. It also emits beta particles with sufficient energy to be therapeutically useful. A single intravenous injection of about 33 mCi (1,221 MBq) was given to each of 20 elderly patients with advanced skeletal metastases from hormonally resistant prostate cancer. Prompt, significant relief of pain occurred 80% of the time with no significant side effects and only minimal, transient marrow toxicity. Re-186(Sn) HEDP appears to be a useful new agent for the palliation of painful osseous metastases in prostate cancer.

Adenocarcinoma↗
PubMed1979

Dose to the liver and spleen in pediatric patients undergoing technetium-99m sulfur colloid scans.

Quantitative conjugate view external counting techniques were applied to determine radiation dose to the liver and spleen in pediatric patients undergoing 99mTc-sulfur colloid (Tc-SC) liver scans. The effective half-life of 99mTc-SC was 5.8 +/- 0.23 hours and 5.2 +/- 0.68 hours in the liver and spleen, respectively. Dose per administered activity ranged from 0.34 to 0.63 rad/mCi (92 to 170 muGy/MBq) for the liver and 0.35 to 1.96 rad/mCi (95.0 to 530.0 muGy/MBq) for the spleen. The spleen to liver dose ratio ranged from 1.0 to 4.9. These values are compared with results extrapolated from published adult data to the pediatric population.

Adolescent↗
PubMed1979

A commercial digoxin radioassay modified for use as an emergency ("stat") procedure.

A recent "stat" procedure recommended by the manufacturer for use with a commercial digoxin radioassay involves doubling the amount of antibody used in the regular procedure, to compensate for the decrease in binding that results from use of a shorter (10 min) incubation. This has two obvious disadvantages: increased material cost and decreased sensitivity because of the increase in the binding capacity of the assay. In our modified procedure, we kept the binding capacity constant by decreasing the volume of the incubation mixture without increasing the amount of antibody. Total binding and the rate of binding on 10-min incubation are 50.4 and less than 1.3% per minute, respectively. Results by our modified stat procedure compare well with those by the manufacturer's suggested regular procedure in terms of sensitivity, accuracy, and precision, and are more sensitive and economical than those by the manufacturer's suggested stat procedure.

Digoxin↗
PubMed1979

A statistical method for determining normal ranges from laboratory data including values below the minimum detectable value.

Determination of normal ranges from laboratory data containing undectable values is a frequently encountered problem in the radioimmunoassay of peptide hormones. In the past, such determinations usually have been based on the mid-point method or the one-end Winsorized method. A graphic method involving the use of probability paper has also been reported. We propose that the maximum-likelihood estimation is a more appropriate statistical method for the determination of normal range from this type of data (Type I censored data). With this method, the mean and standard deviation, and hence the tolerance limits, can be estimated. We used the maximum-likelihood estimation method to determine the normal range of serum thyrotropin values obtained from 93 healthy subjects, based on a log normal distribution. Although the serum thyrotropin content was undetectable in 14% of the subjects, a normal range could be calculated. Using tolerance limits for 95% coverage of the population with 90% confidence, we calculated the normal range of thyrotropin to be 0.51-5.75 milliunits/L, with a mean value of 1.71 milliunits/L, and predicted that 91.4% of undetectable serum thyrotropin values will fall within the normal range.

Humans↗
PubMed1978

Dose to the metaphyseal growth complexes in children undergoing 99mTc-EHDP bone scans.

The spatial temporal distribution of radionuclides in children may differ greatly from that accepted for adults. Following injection of a bone-seeking agent (99mTc-EHDP), radioactivity in the metaphyseal growth complexes of the distal femur and proximal tibia was quantitated in a series of children 4 to 16 years of age, using a gamma camera/computer system. The dose to the growth plate was fount to range from 0.8 to 4.7 rads when adjusted to an administered activity of 200 muCi/kg, compared to approximately 0.6 rad to the adult skeleton for a corresponding study.

Adolescent↗
PubMed1978

Clinical comparison of technetium-99m diphosphonate and pyrophosphate in bone scintigraphy: concise communication.

Thirty patients had bone scintigraphy with both Tc-99m pyrophosphate (Tc-PPi) and Tc-99m diphosphonate (Tc-HEDP). The images were given a composite rating for quality and the basis of three sets of criteria, and were also compared for the number of lesions detected by each agent. The two agents provided no difference in scan quality. Nevertheless, in ten of the 30 patients, at least two of the three readers detected with Tc-HEDP lesions that were not seen with Tc-PPi, and in two such cases all three readers considered the Tc-PPi scan normal. In another of these ten, two of three readers felt the Tc-PPi image was norm, whereas all three detected the lesion with Tc-HEDP. The reverse never occurred (P less than 0.01).

Bone Neoplasms↗
PubMed1978

Emergency procedure for digoxin radioassay.

A rapid but precise radioassay for digoxin has been developed by optimizing the conditions for antigen-antibody interaction and for separation of bound and free fractions. This new procedure involves incubation of radioactively labeled antigen, antibody, and standard or sample at 3 degrees C for 10 min. Charcoal is then added, the mixture centrifuged for 5 min, and the radioactivity of the supernate counted. Results are available in less than 1 h after receipt of the specimens, making the procedure suitable for emergency determinations. Results correlate well with those by our routine procedure (Becton Dickinson) (r = 0.9739, y = 0.0356 + 0.9915x, n = 49). Analytical recovery of added pure digoxin exceeds 94%, both within and between assay CV's are less than 8%.

Antigen-Antibody Reactions↗
PubMed1978

Hypercalcemia in thyrotoxicosis.

Hypercalcemia occurs in approximately one of every five patients with thyrotoxicosis, and one of seven patients with hypercalcemia and thyrotoxicosis will have hyperparathyroidism as the cause of the serum calcium elevation. While there are no clinical features which permit easy identification of patients with hyperparathyroidism and thyrotoxicosis, determination of serum parathyroid hormone levels may help. Parathyroid hormone levels may be normal or suppressed if hypercalcemia is due to hyperthyroidism alone, and an elevated parathyroid hormone level suggest coexisting hyperparathyroidism.

Adult↗
PubMed1977

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.

Adolescent↗
PubMed1977

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.

Half-Life↗
PubMed1977

Metastatic pulmonary calcification in primary hyperparathyroidism.

Metastic pulmonary calcification (MPC) developed in a patient with primary hyperparathyroidism. Renal function was only minimally impaired (creatine clearance of 65 ml/min) the day prior to appearance of the lung infiltrate, but deteriorated (creatinine clearance of 14 ml/min) concomitantly with the appearance of MPC. Lung imaging with 99mTc bone-scanning agents helps differentiate MPC from other problems with similar clinical and roentgenographic findings, thus allowing prompt therapy.

Calcinosis↗