Heavy ion therapy has two definite advantages: good dose localization and higher biological effect. Range calculation of the heavy ions is an important factor in treatment planning. X-ray CT numbers are used to estimate the heavy ion range by looking up values in a conversion table which relates empirically photon attenuation in tissues to particle stopping power; this is one source of uncertainty in the treatment planning. Use of positron emitting radioactive beams along with a positron emission tomograph or a positron camera gives range information and may be used as a means of checking in heavy ion treatment planning. However, the metabolism of the implanted positron emitters in a living object is unpredictable because the chemical forms of these emitters are unknown and the metabolism is dependent on the organ species and may be influenced by many factors such as blood flow rate and fluid components present. In this paper, the washout rate of 11C activity implanted by injecting energetic 11C beams into thigh muscle of a rear leg of a rabbit is presented. The washout was found to consist of two components, the shorter one was about 4.2 +/- 1.1 min and the longer one ranged from 91 to 124 min. About one third of the implanted beta+ activity can be used for imaging and the rest was washed out of the target area.

Gamma-seminoprotein (gamma-Sm), a potential new marker for prostate cancer, has been evaluated with a sandwich-type enzyme immunoassay (EIA). This assay system has been confirmed to have a sensitivity and detectable range of 3.0 and 3.0-100 ng/ml, respectively, with a high reproducibility (approximately equal to 6% coefficient of variation between assays). A total of 256 serum samples were drawn from normal Japanese subjects for detection of gamma-Sm. Serum gamma-Sm was undetectable (less than 3.0 ng/ml) in 26 samples from 26 females. In 230 male cases, serum gamma-Sm levels ranged from less than 3.0 to 4.0 ng/ml. These values were not related to age. An upper normal limit of 3.6 ng/ml was calculated for 99 percentile Japanese males (n = 103) over 50 years of age. Serum gamma-Sm was detected in 192 untreated male patients with urological diseases. Gamma Sm levels (mean +/- SD) in each disease were as follows: prostate cancer (n = 64) 11.0 +/- 17.9 ng/ml; benign prostatic hypertrophy (n = 50), 3.02 +/- 0.113; bladder cancer (n = 58), 3.13 +/- 0.514; and renal adenocarcinoma (n = 30), 3.26 +/- 1.01. Serum gamma-Sm levels were statistically higher (p less than 0.05) in the prostate cancer group, however, there was no statistical difference in gamma-Sm levels among clinical stages or histopathologic grades. Furthermore, serum gamma-Sm values showed no correlation (r = 0.3870) with prostatic acid phosphatase (PAP), but were slightly correlated to prostate antigen (PA) levels (r = 0.6980) in patients with prostate cancer. These results suggest that gamma-Sm is a potential tumor marker of prostate cancer and that serially detected serum gamma-Sm levels could be used to monitor the disease.

No abstract

Serum prostate-specific antigen (PA) values detected by a newly developed enzyme immunoassay (EIA, MARKIT-M PA) as a successor of MARKIT-F PA, which has been a leading kit in Japan, were evaluated for its role in the diagnosis of cancer of the prostate and follow-up of the patients afflicted with the disease. The system is one-step sandwich type EIA using horseradish peroxidase as a tracer and has 0.50-100 ng/ml of detectable range with small amount of sample volume (25 microliters) and reliable quality control data. Furthermore, serum PA values detected by the assay were almost equivocal to those detected by MARKIT-F PA. Serum PA values in prostate cancer patients (n = 122) were statistically higher than those in normal males (n = 90), urological malignancies other than prostate cancer (n = 48) or benign prostatic hypertrophy (BPH, n = 73). Even in the patients with stage A and B prostate cancer, serum PA values were observed to be statistically higher than those in BPH cases. If 3.6 ng/ml was used, which is normal value in MARKIT-F PA, as a cut-off value and BPH cases as a control, the sensitivity, specificity and efficacy for diagnosis of prostate cancer were 77.9, 91.8 and 83.1%, respectively, which showed the best results during the range examined. Serially determined serum PA values in following up the patients with prostate cancer were confirmed to be highly effective to evaluate treatment responses. These results suggest that MARKIT-M PA is thought to be one of the best tool for determination of serum PA values.

No abstract