Safe radiation exposure of medical personnel by using simple methods of radioprotection while administering 131I-lipiodol therapy for hepatocellular carcinoma.

The intra-arterial administration of 131I-lipiodol is a therapeutic approach increasingly used for the treatment of inoperable hepatocellular carcinomas. This technique has even become the reference treatment for hepatocellular carcinomas with portal thrombosis and is the only effective treatment to reduce the risk of recurrence among patients who could benefit from surgical operation. Currently, few data have been published concerning the levels of exposure for personnel carrying out this type of treatment. We undertook a dosimetric study targeted mainly on the exposure of the person performing the injection of 131I-lipiodol to show that this treatment can be carried out with an exposure at the extremities distinctly lower than the regulatory annual threshold by using simple means of radioprotection. The point of puncture was carried out at the level of left femoral artery, the preparation and injection of the therapeutic dose was carried out extemporaneously by the nuclear medicine specialist using a 10 ml syringe (for an injected volume of 4 ml) fitted with an adapted syringe protector. The injection was carried out as rapidly as possible under scopic control while avoiding reflux, with compression carried out by the radiologist. This study comprises 52 intra-arterial injections of 131I-lipiodol (2016+/-92 MBq). For the nuclear medicine specialists, 52 measurements were carried out at the level of the thorax and 41 on the fingers. For the radiologists, 22 measurements were carried out at the level of the thorax and six on their index fingers; nine measurements were carried out at the level of the thorax for the technologist and four at the level of the thorax for the stretcher bearer. For the nuclear medicine specialists, the average dose received at the level of the fingers varies between 140 and 443 microSv (according to the fingers) and the average dose at the thorax is 17 microSv. For the radiologists, the average dose received is 215 microSv at the level of the fingers and 15 microSv at the thorax. These results show that the administration of high therapeutic activities of 131I-lipiodol can be carried out for the exposed personnel with a dose at the level of the fingers much lower than the European regulatory limit of 500 mSv.

Patient dosimetry for 131I-lipiodol therapy.

Patient dosimetry data for intra-arterial()iodine-131 lipiodol therapy for hepatocellular carcinoma (HCC) are scarce. The aim of this study was to determine the absorbed dose (D) to the tumour and healthy tissues, as well as the effective dose (E), by different methods for 17 therapies in 15 patients who received a mean activity of 1.9 GBq (SD 0.2) (131)I-lipiodol. Eight patients received thyroid blocking by potassium iodide (KI). Patient dosimetry was performed based on bi-planar total body scans using the Monte Carlo simulation program MCNP-4B and the MIRDOSE-3 standard software program. CT images of each patient were used to determine liver and tumour volume and position. The total body dose to the patient was also determined by biological dosimetry with the in vitro micronucleus (MN) assay. From the increase in micronucleus yield after therapy, the equivalent total body dose (ETBD) was calculated. Results for D and E were comparable between MCNP and MIRDOSE (liver: mean 7.8 Gy, SD 1.8, lungs: 6.8 Gy, SD 2.9, E: 2.01 Gy, SD 0.58). MIRDOSE gave a systematic overestimation for the tumour dose, especially for tumours <3 cm (15%). The MCNP method is more accurate since the dose contributions from tumour to organs and vice versa can be accounted for. The absorbed dose to the thyroid was significantly lower for patients who received KI (7.2 Gy, SD 2.2) than for the other patients (13.8 Gy, SD 5.0). MN yields could be obtained for only 12 of the 17 therapies due to hypersplenism. A mean ETBD of 1.66 Gy (SD 0.73) was obtained, but the MN results showed no correlation between the ETBD and the total body dose values of the physical dosimetry. Also, in all except one of the patients, no further reduction in the number of thrombocytes was observed after therapy, probably due to the existing hypersplenism. It is concluded that in view of the high E values, patient dosimetry is necessary for patients receiving (131)I-lipiodol therapy. Except in the case of the smaller tumours, comparable results were obtained with MCNP and MIRDOSE. Due to hypersplenism, biological dosimetry results based on the MN assay are not reliable.

Accumulation of iodized oil within the nonneoplastic liver adjacent to hepatocellular carcinoma via the drainage routes of the tumor after transcatheter arterial embolization.

PURPOSE: After transcatheter arterial embolization (TAE) with iodized oil (Lipiodol), a relatively dense accumulation of Lipiodol is often seen in the nontumorous liver adjacent to a hypervascular hepatocellular carcinoma (HCC) nodule. We compared this phenomenon with the findings obtained with single-level dynamic CT during hepatic arteriography (SLDCTHA) and presumed its possible mechanism. METHODS: Fifty-six patients with HCC underwent hepatic angiography including SLDCTHA followed by segmental or subsegmental TAE with a mixture of an anticancer drug and Lipiodol. We compared the drainage area of the HCC depicted on SLDCTHA with the Lipiodol accumulation in the nontumorous liver adjacent to the HCC on CT after TAE (LpCT). RESULTS: In 26 of the 56 patients, a definite corona enhancement around the HCC, suggesting the drainage of blood from the tumor into the surrounding liver parenchyma, was seen on the late phase of SLDCTHA. In 17 of these 26 patients (65.4%), LpCT showed a more intense accumulation of Lipiodol in the nontumorous liver adjacent to the HCC that corresponded to the drainage area revealed on SLDCTHA. CONCLUSION: The drainage of blood from the HCC was considered to be a possible mechanism of the accumulation of Lipiodol in the nontumorous liver adjacent to the HCC.

A new assay for lipiodol in a tumor using a combination of m-chloroperbenzoic acid-mediated oxidation and the iodo-starch reaction.

Lipiodol, an iodine adduct lipid, has been used as a targeting carrier of anticancer drugs in experimental animals and humans. In most studies, the concentrations of the anticancer drugs in tissues and organs have been monitored, but not of the carrier because a simple method for measuring lipiodol in biological organs did not exist. Here we present an analytical method for the quantitative determination of lipiodol in tissue. This method is based on the measurement of iodine released from lipiodol by an oxidative reaction. The released iodine was measured spectrophotometrically by monitoring the iodo-starch reaction. Using this method, we were able to demonstrate the tumor specificity of lipiodol using rabbits bearing VX2 tumors in the liver. The present method is also expected to be applicable to human cancers, such as hepatic and colon cancer.

Safety and pharmacokinetics of iotrolan in hysterosalpingography. Retention and irritability compared with Lipiodol.

RATIONALE AND OBJECTIVES: The authors compared the safety and pharmacokinetics of Iotrolan (water-soluble) in hysterosalpingography (HSG) with those of Lipiodol (oil-soluble). METHODS: Iotrolan and Lipiodol were administered intraperitoneally at doses of 100 mg iodine/kg to female rabbits. Retention in the body was investigated by x-ray imaging, plasma kinetics, and urinary and fecal excretion. Irritability in the abdomen was investigated by histologic examination. RESULTS: Iotrolan was entirely excreted into the urine within 2 days after administration. Conversely, Lipiodol was excreted into the urine, had a half-life of 50 days, and was retained for more than 21 days in the abdomen. Iotrolan induced no inflammatory reaction in the abdomen, whereas Lipiodol induced a marked abdominal inflammatory reaction, including granuloma formation. Iotrolan had no effect on iodine concentration in the thyroid; Lipiodol increased iodine concentration significantly. CONCLUSIONS: Iotrolan, which is a water-soluble and nonionic dimeric contrast medium, has potential greater safety for use in HSG than Lipiodol.

Studies on anticancer treatment with an oily anticancer drug injected into the ligated feeding hepatic artery for liver cancer.

In six adult patients with nonresectable liver cancer, as well as in mature New Zealand white rabbits with implanted VX2 carcinoma in the liver, the artery feeding the hepatic lobe with the malignant lesion was ligated, and an oily contrast medium (Lipiodol Ultra-Fluid) was injected into the hepatoproximal lumen of the ligated artery of the liver with carcinoma. The oily contrast medium was detected in all the branches of the artery injected, and thereafter was found only in tumor tissue for 7 days experimentally and for 16 months clinically. Taking advantage of this phenomenon, the therapeutic effect of the injection of an oily anticancer drug (bleomycin oil suspension) into the hepatoproximal lumen of the ligated hepatic artery was investigated in rabbits with VX2 carcinoma of the liver. The mean concentration level of bleomycin in the tumor tissue was 2.4 +/- 0.4 microgram/g 1 week after the injection of bleomycin oil suspension (1.5 mg potency/kg) in three rabbits. However, its concentration level in nontumorous tissue of the liver was undetectably low in two rabbits, but 0.6 microgram/g in the third rabbit. The group of rabbits receiving an injection of bleomycin oil suspension into the ligated artery had a significantly longer mean survival time than those of the experimental group receiving an injection of saline solution of bleomycin into the ligated artery as well as the three other groups treated (P less than 0.02, N = 5 for each group). It may be concluded that an oily anticancer drug injected into the hepatoproximal lumen of the ligated hepatic artery can intensify the anticancer effects of a ligation of the hepatic artery for liver cancer.