• Progress in Medical Physics
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• v.10 no.1
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• pp.1-7
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• 1999

In this study, the dose distributions of a $^{32}$ p uniform cylindrical volume source and a surface source, a pure $\beta$emitter, were calculated in order to obtain information relevant to the utilization of a balloon catheter and a radioactive stent. The dose distributions of $^{32}$ p were calculated by means of the EGS4 code system. The sources are considered to be distributed uniformly in the volume and on the surface in the form of a cylinder with a radius of 1.5 mm and length of 20 mm. The energy of $\beta$particles emitted is chosen at random in the $\beta$ energy spectrum evaluated by the solution of the Dirac equation for the Coulomb potential. Liquid water is used to simulate the particle transport in the human body. The dose rates in a target at a 0.5mm radial distance from the surface of cylindrical volume and surface source are 12.133 cGy/s per GBq (0.449 cGy/s per mCi, uncertainty: 1.51%) and 24.732 cGy/s per GBq (0.915 cGy/s per mCi, uncertainty: 1.01%), respectively. The dose rates in the two sources decrease with distance in both radial and axial direction. On the basis of the above results, the determined initial activities were 29.69 mCi and 1.2278 $\mu$Ci for the balloon catheter and the radioactive stent using $^{32}$ P isotope, respectively. The total absorbed dose for optimal therapeutic regimen is considered to be 20 Gy and the treatment time in the case of the balloon catheter is less than 3 min. Absorbed doses in targets placed in a radial direction for the two sources were also calculated when it expressed initial activity in a 1 mCi/ml volume activity density for the cylindrical volume source and a 0.1 mCi/cm$^2$ area activity density for the surface source. The absorbed dose distribution around the $^{32}$ P cylindrical source with different size can be easily calculated using our results when the volume activity density and area activity density for the source are known.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.481-487
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• 2023

In this study, we analyzed the incidence of side effects of photoneutron dose according to the number of beams during intensity-modulated radiotherapy of prostate cancer using 15 MV. The radiation treatment plan design for intensity-modulated radiation therapy for prostate cancer was established with a prescription dose of 220 cGy per dose and a total of 7260 cGy for 33 treatments. The linear accelerator used in the experiment is Varian's True Beam STx (Varian, USA). Photoneutron dose was generated by using 15 MV energy in the planning target volume (PTV). The treatment plan was designed with IMRT 5, 7, and 9 portals using the Eclipse System (Varian Ver 10.0, USA). An optically stimulated luminescence albedo neutron dosimeter (Landauer Inc., USA) was used to measure photoneutron dose. IMRT 5 portals, 1.7 per 1,000, 7 portals, 1.8 per 1,000, 9 portals, 2.0 per 1,000 were calculated as the probability of experiencing side effects on the thyroid gland due to photoneutron dose. This study studies the risk of secondary radiation exposure dose that can occur during intensity-modulated radiation therapy, and it is considered that it will be used as useful data in relation to stochastic effects in the future.

• Journal of Radiation Protection and Research
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• v.46 no.2
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• pp.39-47
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• 2021

Background: The National Institutes for Quantum and Radiological Science and Technology-National Institute of Radiological Sciences (QST-NIRS) has continuously investigated the undesired radiation exposure in ion beam radiotherapy mainly in carbon-ion radiotherapy (CIRT). This review introduces our investigations on the secondary neutron dose in CIRT with the broad and scanning beam methods. Materials and Methods: The neutron ambient dose equivalents in CIRT are evaluated based on rem meter (WENDI-II) measurements. The out-of-field organ doses assuming prostate cancer and pediatric brain tumor treatments are also evaluated through the Monte Carlo simulation. This evaluation of the out-of-field dose includes contributions from secondary neutrons and secondary charged particles. Results and Discussion: The measurements of the neutron ambient dose equivalents at a 90#x00B0; angle to the beam axis in CIRT with the broad beam method show that the neutron dose per treatment dose in CIRT is lower than that in proton radiotherapy (PRT). For the scanning beam with the energy scanning technique, the neutron dose per treatment dose in CIRT is lower than that in PRT. Moreover, the out-of-field organ doses in CIRT decreased with distance to the target and are less than the lower bound in intensity-modulated radiotherapy (IMRT) shown in AAPM TG-158 (American Association of Physicists in Medicine Task Group). Conclusion: The evaluation of the out-of-field doses is important from the viewpoint of secondary cancer risk after radiotherapy. Secondary neutrons are the major source in CIRT, especially in the distant area from the target volume. However, the dose level in CIRT is similar or lower than that in PRT and IMRT, even if the contributions from all radiation species are included in the evaluation.

• Radiation Oncology Journal
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• v.29 no.4
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• pp.219-227
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• 2011

Purpose: This study evaluated the treatment effectiveness and proper radiation dose of helical tomotherapy (HT) in spine oligometastases from gastrointestinal cancers. Materials and Methods: From 2006 to 2010, 20 gastrointestinal cancer patients were treated with HT for spine oligometastases (31 spine lesions). The gross tumor volume (GTV) was the tumor evident from magnetic resonance imaging images fused with simulation computed tomography images. Clinical target volume (CTV) encompassed involved vertebral bodies or dorsal elements. We assumed that the planning target volume was equal to the CTV. We assessed local control rate after HT for 31 spine metastases. Pain response was scored by using a numeric pain intensity scale (NPIS, from 0 to 10). Results: Spine metastatic lesions were treated with median dose of 40 Gy (range, 24 to 51 Gy) and median 5 Gy per fraction (range, 2.5 to 8 Gy) to GTV with median 8 fractions (range, 3 to 20 fraction). Median biologically equivalent dose (BED, ${\alpha}/{\beta}$ = 10 Gy) was 52 $Gy_{10}$ (range, 37.5 to 76.8 $Gy_{10}$) to GTV. Six month local control rate for spine metastasis was 90.3%. Overall infield failure rate was 15% and outfield failure rate was 75%. Most patients showed pain relief after HT (93.8%). Median local recurrence free survival was 3 months. BED over 57 $Gy_{10}$ and oligometastases were identified as prognostic factors associated with improved local progression free survival (p = 0.012, P = 0.041). Conclusion: HT was capable of delivering higher BED to metastatic lesions in close proximity of the spinal cord. Spine metastases from gastrointestinal tumors were sensitive to high dose radiation, and BED (${\alpha}/{\beta}$ = 10 Gy) higher than 57 $Gy_{10}$ could improve local control.

• Journal of the Korean Society of Radiology
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• v.18 no.4
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• pp.383-389
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• 2024

In this study, we aimed to analyze the probability of secondary cancer occurring in the abdomen, a normal organ, due to photoneutron exposure during intensity-modulated radiotherapy for prostate cancer. The design of the radiation treatment plan for prostate cancer was established as a daily prescription dose of 220 cGy, a total of 35 treatments, and 7700 cGy. The experimental equipment was a True Beam STx (Varian, USA) linear accelerator from Varian. The energy used in the experiment was 15 MV, and the treatment plan was designed so that the photoneutron dose would be generated within the planning target volume (PTV). The radiation treatment plan was an Eclipse System (Varian Ver. 10.0, USA), and the number of irradiation portals was set to 5 to 9. The irradiation angle was designed so that 95% of the prescription dose area was set to 0 to 320°, and the number of beamlets per irradiation portal was set to 100. The optically stimulated luminescence dosimeter used in this study to measure the dose of photoneutrons was designed to measure photoneutron doses by coating ⁶LiCO₃ on a device containing aluminum oxide components. It was studied that there is a minimum of 7.07 to 11 cases per 1,000 people with secondary cancer due to the photoneutron dose to the abdomen during intensity-modulated radiotherapy. In this study, we studied the risk of secondary radiation dose that may occur during intensity-modulated radiotherapy, and we expect that this will be used as meaningful data related to the probabilistic effects of radiation in the future.

• Journal of Veterinary Clinics
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• v.14 no.2
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• pp.195-200
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• 1997

In order to compare the pharmacokinetic profiles of enrofloxacin-HCL)ENFLX-HCL) and enrofloxacin-KOH (ENFLX-KOH) after oral administration in broiler chickens, the study was performed. The chickens used in this study weighed $1.82 {\pm}0.2 kg$ and clinically healthy. The dose of intravenous and lral administration was 5 mg per kg of body weight as enrofloxacin. After intravenous injection of enrofloxacin, it showed two-compartment model with the rapid distribution phase and the slow elimination phase. The mean apparent volume of distribution (Vd) was 2.70 l/kg. The mean half-life of elimination and distribution showed 8.26 h and 0.44 h, respectively. The mean area under curve (AUC) was calculated as $19.7 {\mu} g{\cdot} h/ml$. After oral administration of ENFLX-HCL and ENFLX-KOH with a rate of dose 5 mg of enrofloxacin/kg of body weight, Both of the products were showed one-compartment model unlike that of i.v. enrofloxacin standard solution showed the mean bioavailability of 79.64% for the ENFLX-KOG and 86.24% for the ENFLX-HCL. The mean total body clearance of the former was 0.24 l/kg/h and the latter 0.42 l/kg/h. Both enorfloxacin formulations seemed to have good tissue distribution and penetration as indicated by large volume of distribution : 2.72 l/kg for the -KOH and 4.44 l/kg for the -HCL. With the results obtained in this study, ENFLX-HCL could be used in place of its salt form in chickens.

• Radiation Oncology Journal
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• v.14 no.1
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• pp.41-52
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• 1996

Purpose : This paper reports a dosimetric study of 88 patients treated with a combination of external radiotherapy and high dose rate ICR for FIGO stage IIB carcinoma of the cervix. The purpose is to investigate the correlation between the radiation doses to the rectum, external radiation dose to the whole pelvis, ICR reference volume, TDF BED and the incidence of late rectal complications, retrospectively. Materials and Methods : From November 1989 through December 1992, 88 patients with stage IIB cervical carcinoma received radical radiotherapy at Department of Radiation Oncology in Yonsei University Hospital. Radiotherapy consisted of 44-54 Gy(median 49 Gy) external beam irradiation plus high dose rate intracavitary brachytherapy with 5 Gy per fraction twice a week to a total dose of 30 Gy on point A. The maximum dose to the rectum by contrast(r, R) and reference rectal dose by ICRU 38(dr, DR) were calculated. The ICR reference volume was calculated by Gamma Dot 3.11 HDR planning system, retrospectively The time-dose factor(TDF) and the biologically effective dose (BED) were calculated. Results : Twenty seven($30.7\%$) of the 88 patients developed late rectal complications:12 patients($13.6\%$) for grade 1, 12 patients($13.6\%$) for grade 2 and 3 patients($3.4\%$) for grade 3. We found a significant correlation between the external whole pelvis irradiation dose and grade 2, 3 rectal complication. The mean dose to the whole pelvis for the group of patients with grade 2, 3 complication was Higher, $4093.3\pm453.1$ cGy, than that for the patients without complication, $3873.8\pm415.6$ (0.05$7163.0\pm838.5$ cGy, than that for the Patients without rectal complication, $0772.7\pm884.0$ (p<0.05). There was no correlation of the rate of grade 2, 3 rectal complication with the iCR rectal doses(r, dr), ICR reference volume, TDF and BED. Conclusion : This investigation has revealed a significant correlation between the dose calculated at the rectal dose by ICRU 38(DR) or the most anterior rectal dose by contrast(R) dose to the whole pelvis and the incidence of grade 2, 3 late rectal complications in patients with stage IIB cervical cancer undergoing external beam radiotherapy and HOR ICR. Thus these rectal reference points doses and whole pelvis dose appear to be useful Prognostic indicators of late rectal complication in high dose rate ICR treatment in cervical carcinoma.

• Journal of Acupuncture Research
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• v.40 no.4
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• pp.344-350
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• 2023

Background: 4-carvomenthenol[4-methyl-1-(1-methylethyl)-3-cyclohexen-1-ol] is a main component of Origanum vulgare L., Zanthoxylum piperitum (L.) DC., and other plants. It has been reported to exhibit anti-inflammatory, antibacterial, and anti-tumor effects. Furthermore, it is necessary to conduct a toxicity test on 4-carvomenthenol to ensure its safety. Methods: This study included 5-week-old Institute of Cancer Research mice that were categorized into 3 treatment groups (12, 25, and 50 mg/kg 4-carvomenthenol dose levels) and a control group (10% dimethyl sulfoxide, 40% polyethylene glycol 300, 5% Tween 80, and 45% normal saline injection of the final volume), with 5 male mice and 5 female mice per group. All groups were observed for clinical symptoms and body weight in a period of 14 days and were subjected to gross necropsy after euthanasia. Results: No deaths were recorded. No test substance-related clinical signs in the female mice of the 12 mg/kg dose group were observed. Abnormal gait was observed in 1 male from day 1 to day 3 in the 12 mg/kg dose group; 1-3 males from day 1 to day 7 and 1-5 females from day 1 to day 15 in the 25 mg/kg dose group; and 2-5 males and 2-5 females from day 1 to day 15 in the 50 mg/kg dose group. No test substance-related effect on the body weight and necropsy findings was observed. Conclusion: The results of this study suggested that the lethal dose of 4-carvomenthenol could be greater than 50 mg/kg. However, further research is needed, especially repeated-dose toxicity studies, to confirm the efficacy and safety of 4-carvomenthenol.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.303-309
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• 2017

To evaluate the usefulness of 3-dimensional brachytherapy(BT) planning technique based on CT in cervical cancer. Patients with cervical cancer underwent 2-D BT treatment planning and then CT scan with HDR intracavitary applicators in place with same positions. Dose was prescribed to Point A with 5Gy per fraction on 2-D BT planning. For 3-D BT planning, and dose was prescribed to the High risk CTV for BT (HR CTV) with 5Gy. The 3-D BT planning goal was to cover at least 90% of the HR CTV with target 5Gy isodose surface while limiting the dose to $2cm^3$ of bladder to less than 7.5 Gy, and $2cm^3$ of rectum to less than 5Gy. In one patient of 10 patients, $D_{2cm3}$ of rectal dose was over 5Gy and 6patients at $D_{2cm3}$ of bladder dose on 2-D BT planning. There was a tendency to underestimate ICRU bladder dose than ICRU rectal dose. CT based 3-D BT planning for cervical cancer will enable evaluation of dose distributions for tumor and critical organs at risk. So, rectal and bladder morbidity as well as geographic miss will be reduced in case of the bulky disease or uterine malposition.

• Progress in Medical Physics
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• v.6 no.1
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• pp.49-57
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• 1995

The semiconductor detector has a high sensitive to radiation and a small volume. It has been frequently used in high energy photon and electron beamdosimetry. However, Semiconductor detector are subject to radiation damage in high energy radiation beam which reduces the sensitivity and creat a large discrepancy. In this experiments, P-type semiconductor was irradiated to 18 MeV electron beam with pre-irradiation for reducing the sensitivity for high reproducibility and investigated the dose characteristics against the dose rate variations. The sensitivity per unit dose in small dose rate showed a 35％ large different to a large dose rate with pre-irradiation dose for 0.5 KGy and 20％ for 3 KGyin this study. The silicon detector has showed a large dependency of beam direction with 13％ discrepancy and a linear sensitive as increased temperature.