• Title/Summary/Keyword: Minimum effective dose

Search Result 73, Processing Time 0.034 seconds

Patient Specific Quality Assurance of IMRT: Quantitative Approach Using Film Dosimetry and Optimization (강도변조방사선치료의 환자별 정도관리: 필름 선량계 및 최적화법을 이용한 정량적 접근)

  • Shin Kyung Hwan;Park Sung-Yong;Park Dong Hyun;Shin Dongho;Park Dahl;Kim Tae Hyun;Pyo Hongryull;Kim Joo-Young;Kim Dae Yong;Cho Kwan Ho;Huh Sun Nyung;Kim Il Han;Park Charn Il
    • Radiation Oncology Journal
    • /
    • v.23 no.3
    • /
    • pp.176-185
    • /
    • 2005
  • Purpose: Film dosimetry as a part of patient specific intensity modulated radiation therapy quality assurance (IMRT QA) was peformed to develop a new optimization method of film isocenter offset and to then suggest new quantitative criteria for film dosimetry. Materials and Methods: Film dosimetry was peformed on 14 IMRT patients with head and neck cancers. An optimization method for obtaining the local minimum was developed to adjust for the error in the film isocenter offset, which is the largest part of the systemic errors. Results: The adjust value of the film isocenter offset under optimization was 1 mm in 12 patients, while only two patients showed 2 mm translation. The means of absolute average dose difference before and after optimization were 2.36 and $1.56\%$, respectively, and the mean ratios over a $5\%$ tolerance were 9.67 and $2.88\%$. After optimization, the differences in the dose decreased dramatically. A low dose range cutoff (L-Cutoff) has been suggested for clinical application. New quantitative criteria of a ratio of over a $5\%$, but less than $10\%$ tolerance, and for an absolute average dose difference less than $3\%$ have been suggested for the verification of film dosimetry. Conclusion: The new optimization method was effective in adjusting for the film dosimetry error, and the newly quantitative criteria suggested in this research are believed to be sufficiently accurate and clinically useful.

Evaluation of the usefulness of the method according to changes in patient breathing during chest 4D CT imaging (흉부 4D CT에서 호흡 변화에 대한 일시 중지 및 재개 방법의 유용성 평가)

  • Heo, Sol;Shin, Chung Hun;Jeong, Hyun Sook;Yoo, Soon Mi;Kim, Jeong Mi;Yun, In Ha;Hong, Seung Mo;Back, Geum Mun
    • The Journal of Korean Society for Radiation Therapy
    • /
    • v.33
    • /
    • pp.47-54
    • /
    • 2021
  • Purpose : In order to evaluate the usefulness of clinical application of the Pause & Resume methods by comparing and analyzing the data stability and dose reduction effect when repeat scan assuming irregular breathing and using the Pause & Resume method during chest 4D CT using QuasarTM Phantom. Materials and Methods : Using the QuasarTM Phantom, set the breathing rate per minute to 15 BPM and 7.5 BPM, and set the S15 point as an irregular breathing section, and then placed OSLD to this point and use the Pause & Resume method to measure the dose of S15. CTDIvol, DLP, and ALARA-CT were used for comparative analysis of radiation dose between Pause & Resume method and Repeat-scan. In order to evaluate the stability and usability of the data applying the Pause & Resume method, the captured images were sorted by Advanced Workstation Volume Share7 and then sent to EclipseTM, the diameter and volume were analyzed by forming a contour on the iron ball in the QuasarTM Phantom Results : When using Pause & Resume, the dose of OSLD measurement increased by 1.97 times in the section of S15. As a result of image evaluation, the average value of all volumes measured with and without the Pause & Resume method at 15 BPM and 7.5 BPM was 15.2 cm3±0.5%.Allthemeasuredvaluesfor the radius of iron ball were 3.1 cm regardless of whether Pause & Resume method was used or not. In the case of using Pause & Resume, 33% decreased from the lowest DLP value and 38% decreased from the highest DLP value of repeat scan, and the effective dose also decreased 32.1% from the minimum value and 37.6% from the maximum value. Conclusion: Irradiation dose was increased by Pause & Resume method because of the repeat scan on the S15 site where assuming irregular breathing occurred, However Pause & Resume method led to a significant reduction in dose on overall scan range. It also proved the usefulness of clinical application of the Pause & Resume method as a result of similar diameters and volumes of iron ball measurement.

Comparison of Treatment Plans with Multileaf Collimators of different Leaf Width (Leaf width가 다른 다엽 콜리메터에 의한 치료계획 비교)

  • Kim Joo Young;Park Sung Yong;Lee Doo Hyun;Lee Seok Ho;Kim Tae Hyun;Cho Kwan Ho
    • Progress in Medical Physics
    • /
    • v.15 no.4
    • /
    • pp.173-178
    • /
    • 2004
  • Purpose: To compare desimetrically intensity-modulated radiotherapy treatment plans with commercially available multileaf collimators (MLCs) of different leaf width for intracranial lesions. Materials and Methods: Twelve patients with intracranial lesions were treated with BrainLAB's micro-MLCs (mMLCs) and performed with the BrainSCAN ver. 5.2 planning software. They were replanned using the Varian 120 and 80 MLCs. These collimators have minimum leaf width of 3 mm, 5 mm and 10 mm at isocenter, respectively. PTV was $3.3~339.2\textrm{cm}^3$ and the number of beams was 3~7. These three plans were compared with respect to the uniformity and the conformity indices, doses to critical organ and normal tissue. Results: For the uniformity index of the planning target volume (PTV), there were no statistically significant differences between mMLCs and 120 MLCs (p=0.057) and between 120 MLCs and 80 MLCs (p=0.388). However, there was a difference between mMLCs and 80 MLCs (p<0.001). Maximum target dose to the PTV showed no dependency with respect to the leaf width. On the contrary, there were statistically significant differences in the conformity indices between mMLCs and 120 MLCs (p=0.003), between mMLCs and 80 MLCs (p=0.003) and between 120 MLCs and 80 MLCs (p=0.003). The volume of brainstem irradiated to $\geq$70% dose and to $\geq$50% dose was increased as the leaf width of MLCs increased. In particular, the volume of normal tissue irradiated is obviously changed for different leaf width. Volumetric increments for MLCs with leaf widths of 5 mm and 10 mm were 6.3% and 23.2% to the normal tissue irradiated to $\geq$50% dose, and 8.7% and 32.7% to the normal tissue irradiated to $\geq$70% dose, respectively, compared to the volume for MLCs with leaf width of 3 mm. Conclusions: The uniformity index and maximum target dose to the PTV showed no dependency with respect to leaf width of MLCs. However, the conformity index was improved as the leaf width decreased. For the sparing of normal brain tissue, treatment plans with MLCs of 3 mm leaf width is more effective, compared to ones with MLCs of 5 mm and 10 mm leaf widths.

  • PDF

Dose Related Effects of Poloxamer/Sodium Alginate Mixture in Prevention of Postoperative Adhesion Formation in Dogs (개에서 Poloxamer/Sodium Alginate 혼합물의 용량에 따른 복강 유착방지 효과)

  • Jeong, Won-Seok;Seong, Yun-Sang;Kwon, Young-Sam;Jang, Kwang-Ho
    • Journal of Veterinary Clinics
    • /
    • v.26 no.6
    • /
    • pp.547-555
    • /
    • 2009
  • This study was performed to determine the minimum dose of Poloxamer/Sodium alginate (PX/SA) mixture on preventing intraperitoneal adhesions to evaluate organ toxicity. Twenty five healthy adult mongrel dogs (weighing 4.68${\pm}$1.67 kg) were divided into five experimental groups composed of five dogs respectively; negative control group (NC, non-treated), positive control group (PC, 2% carboxymethyl chitosan solution treated), and experiment 1 group (E1, 0.25 ml PX/SA mixture of abraded area), experiment 2 group (E2, 0.5 ml PX/SA mixture of abraded area), experiment 3 group (E3, 1.0 ml PX/SA mixture of abraded area). Venous blood specimens were collected from all experimental animals for hematologic and biochemical analysis: WBC, fibrinogen, AST, ALT, ALP, BUN and creatinine. The anti-adhesion effect was evaluated using a serosa abrasion model. The denuded ileum was coated with PX/SA mixture, carboxymethyl chitosan solution or neither. The tensile strength of the adhesion site was evaluated with a tensiometer. For histopathological examination, tissue samples of the liver and kidney were collected from all dogs. According to the results, the frequency and tensile strength values for adhesion separation in PX/SA group were significantly lower than those in negative control group (p < 0.05). In E2 group, the tensile strength was significantly decreased in consideration of PX/SA dose. The values of AST, ALT, ALP, BUN and creatinine of the control and the experimental groups showed no statistical differences. No obvious microscopic differences were noted among tissue sections obtained from all groups. The results suggest that PX/SA mixture may be effective on reducing peritoneal adhesion formation in dog and that 0.5 ml PX/SA mixture of abraded area is most effective dose. Moreover, PX/SA mixture was considered not to have toxicity for the liver and the kidney.

Comparison of ondansetron and granisetron for antiemetic prophylaxis in maxillofacial surgery patients receiving general anesthesia: a prospective, randomised, and double blind study

  • Savant, Kiran;Khandeparker, Rakshit Vijay Sinai;Berwal, Vikas;Khandeparker, Purva Vijay;Jain, Hunny
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
    • /
    • v.42 no.2
    • /
    • pp.84-89
    • /
    • 2016
  • Objectives: To compare the efficacy of intravenous ondansetron (4 mg, 2 mL) and granisetron (2 mg, 2 mL) for preventing postoperative nausea and vomiting (PONV) in patients during oral and maxillofacial surgical procedures under general anesthesia. Materials and Methods: A prospective, randomized, and double blind clinical study was carried out with 60 patients undergoing oral and maxillofacial surgical procedures under general anesthesia. Patients were divided into two groups of 30 individuals each. Approximately two minutes before induction of general anesthesia, each patient received either 4 mg (2 mL) ondansetron or 2 mg (2 mL) granisetron intravenously in a double blind manner. Balanced anesthetic technique was used for all patients. Patients were assessed for episodes of nausea, retching, vomiting, and the need for rescue antiemetic at intervals of 0-2, 3, 6, 12, and 24 hours after surgery. Incidence of complete response and adverse effects were assessed at 24 hours postoperatively. Data was tabulated and subjected to statistical analysis using the chi-square test, unpaired t-test, or the Mann-Whitney U-test as appropriate. A P-value less than 0.05 was considered statistically significant. Results: There was no statistically significant difference between the two groups for incidence of PONV or the need for rescue antiemetic. Both study drugs were well tolerated with minimum adverse effects; the most common adverse effect was headache. The overall incidence of complete response in the granisetron group (86.7%) was significantly higher than the ondansetron group (60.0%). Conclusion: Granisetron at an intravenous dose of 2 mg was found to be safe, well tolerated, and more effective by increasing the incidence of complete response compared to 4 mg intravenous ondansetron when used for antiemetic prophylaxis in maxillofacial surgery patients receiving general anesthesia. Benefits of granisetron include high receptor specificity and high potency, which make it a valuable alternative to ondansetron.

Medical Treatment of Laryngopharyngeal Reflux (인후두역류의 약물치료)

  • Chu, Hyung-Ro
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
    • /
    • v.18 no.2
    • /
    • pp.108-112
    • /
    • 2007
  • Otolaryngological manifestations of acid reflux include a wide range of pharyngeal and laryngeal symptoms ; and the constellation of symptoms has been called laryngopharyngeal reflux (LPR). In the absence of definite diagnostic criteria, LPR disease remains a subjective entity. A diagnosis of LPR is usually based on response of symptoms to empirical treatment. Investigative modalities such as pH monitoring and, more recently, impedance studies are generally reserved for treatment failures. LPR usually requires more aggressive and prolonged treatment to achieve regression of both symptoms and laryngeal findings. The suppression of gastric acid and secretion with anti-secretary agents has been the mainstay of medical treatment for patients with acid-related disorders. The suppression of gastric acid secretion achieved with Hz-receptor antagonist $(H_2RA)$ has proved suboptimal for relief of reflux symptoms. The rapid development of tolerance and rebound acid hypersecretion after the with-drawal of $H_2RA$ limit their clinical use. Proton pump inhibitors (PPI) have been proved to be very effective for suppressing intragastric acidity, but the optimal dose and duration is unknown. Current evidence indicates that pharmacologic intervention should include, at a minimum, a 3 month trial of twice daily PPI. Symptoms of LPR improve over 2 months of therapy. The physical findings of LPR resolve more slowly than the symptoms and this continues through out at least 6 months of treatment. For most patients with LPR, twice daily dosing with a PPI is usually recommended for an initial treatment for a period of no less than 6 months treatment, and lifetime treatment may be required.

  • PDF

Bioequivalence Evaluation of Senafen Tablet and Airtal Tablet Containing Aceclofenac 100 mg (아세클로페낙(100mg) 제제인 세나펜 정과 에어할 정의 생물학적동등성 평가)

  • 박은우;송우헌;차영주;최영욱
    • Biomolecules & Therapeutics
    • /
    • v.6 no.4
    • /
    • pp.423-428
    • /
    • 1998
  • Aceclofenac is an orally effective non-steroidal anti-inflammatory agent of the phenylacetic acid derivative. Bioequivalence study of two aceclofenac preparations, the test drug (Senafe $n_{R}$: Daewon Phar-maceutical Company) and the reference drug (Airta $l_{R}$: Daewoong Pharmaceutical Company), was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). Sixteen healthy male volunteers, 24$\pm$4 years old and 63.9$\pm$6.9 kg of body weight in average, were divided randomly into two groups and administered the drug orally at the dose of 100 mg as aceclofenac in a 2$\times$2 crossover study. Plasma concentrations of aceclofenac were monitored by HPLC method for 12 hr after administration. AU $Co_{-12h}$ (area under the plasma concentration-time curve from initial to 12 hr) was calculated by the linear trapezoidal method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{msx}$) were compiled directly from the plasma drug concentration-time data. Student's t-test indicated no significant differences between the formulations in these parameters. Analysis of variance (ANOVA) revealed that there are no differences in AU $Co_{12h}$, $C_{max}$ and $T_{max}$ between the formulations. The apparent differences between the formulations were far less than 20% (e.g., 0.25, 0.01 and 7.32 for AU $Co_{-12h}$, $C_{max}$. and $T_{max}$, respectively). Minimum detectable differences (%) between the formulations at $\alpha$=0.05 and 1-$\beta$=0.8 were less than 20% (e.g., 14.65, 12.47 and 15.46 for AU $Co_{-l2h}$, $C_{max}$ and $T_{max}$, respectively). The 90% confidence intervals for these parameters were also within $\pm$ 20% (e.g.,-10.19~10.68, -8.87~8.89 and -3.69~ 18.33 for AU $Co_{-12h}$, $C_{msx}$ and $T_{max}$, respectively). These results satisfy the bioequivalence criteria of KFDA guidelines, indicating that two formulations of aceclofenac are bioequivalent.quivalent.ivalent.ent.t.ent.

  • PDF

Effects of Egg Shell Membrane Hydrolysates on UVB-radiation-induced Wrinkle Formation in SKH-1 Hairless Mice

  • Yoo, Jin Hee;Kim, Jong Keun;Yang, Hee Jin;Park, Ki Moon
    • Food Science of Animal Resources
    • /
    • v.35 no.1
    • /
    • pp.58-70
    • /
    • 2015
  • This study was conducted to examine the effect of egg shell membrane hydrolysates (ESMH) on wrinkle, UV, and moisture protection for cosmetic use. ESMH were fragmented as whole ESMH (before fractioning), Fraction I (> 10 kDa), Fraction II (3-10 kDa), and Fraction III (< 3 kDa). In order to test whether fractionated ESMH can be used for functional cosmetic materials, we examined not only the level of hyaluronic acid and collagen production, but also the MMP-1 activity using a HaCaT and CCD-986Sk cell line. Our study treated each sample of fractionated ESMH with different concentrations (0.01, 0.1, 1 mg/mL). In our in vivo research, we used hairless mice that had been exposed to UV-B to induce wrinkles for 7 wk, then applied Fraction I to the treatment group for 5 wk and then tested skin thickness, minimum erythema dose and moisture content. In addition, Fraction I was high in collagen and HA biosynthesis and it was better than TGF-${\beta}$ in improving of the skin. When TNF-${\alpha}$ caused MMP-1 activity in the CCD-986Sk cells, the whole ESMH and Fraction I proved to be effective in hindering the induction of collagenase depending on the concentration, and also showed outstanding effects in the suppression of skin aging. We found that the treatment group mice's UV-B radiation-induced skin damage was largely mitigated compared to that of the non-treatment group mice. Thus, we have concluded that EMSH helps to mitigate UV-B radiation-induced wrinkles, collagen, HA, MMP-1 activity and can be used for functional cosmetic materials.

Evaluation of Indoor Radon Levels in a Hospital Underground Space and Internal Exposure (의료기관 지하시설의 라돈가스 측정과 내부피폭 조사)

  • Song, Jea-Ho;Jin, Gye-Hwan
    • Journal of the Korean Society of Radiology
    • /
    • v.5 no.5
    • /
    • pp.231-235
    • /
    • 2011
  • Radium is rock or soil of crust or uranium of building materials and thorium after radioactivity collapse process are created colorless and odorless inert gas that accrue well in sealed space like mine or basement. It inflow to lung circulate respiratory organ and caused lung cancer because of deposition of lung or bronchial tubes. Radium sheath of medical institution treat person's life is possible big danger to professional regarding radioactivity who has much amount exposed radioactivity and weaker immune patient. so we do this test. Using measuring instrument at test is real time radium measuring instrument, Professional Continuous Radon monitor, and measuring places are basement first floor and second floor of two hospitals and measure from 10 a.m to 3 p.m. Measurement result of Professional Continuous Radon monitor is minimum 14.8 Bq/$m^3$ to maximum 70.3 Bq/$m^3$ and show domestic baseline below 148 Bq/$m^3$, effective dose-rate is minimum 0.296 mSv to maximum 1.406 mSv that show 2.4 mSv, 10~58.3% level, exposed radiation amount from nature radiation one year.

Pharmacokinetic Evaluation of Ketorolac Tromethamine Sustained-Release Pellets after Oral Administration in Rabbits (케토롤락트로메타민 서방성 펠렛의 약물속도론적 평가)

  • Kwak, Son-Hyok;Hwang, Sung-Joo;Jiang, Ge;Nam, Kyung-Wan;Moon, Young-Girl;Lee, Hai-Bang;Cho, Sun-Hang;Yuk, Soon-Hong;Lee, Han-Koo;Jeong, Sang-Young;Lee, Young-Won
    • Journal of Pharmaceutical Investigation
    • /
    • v.30 no.4
    • /
    • pp.241-246
    • /
    • 2000
  • To develop a sustained-release preparation containing ketorolac tromethamine, two sustained-release pellet formulations were evaluated with a pharmacokinetic study as compared with a conventional commercial tablets (10 mg $Tarasyn^{TM}$, Roche Korea Ltd.). Two sustained-release formulations were as follows; formulation A was composed of an inner layer containing 75% of drug coated with $Eudragit^{TM}$ RS 100 membrane and an outer layer containing 25% of drug mixed with $Eudragit^{TM}$ NE30D, and formulation B was composed of only an inner layer containing 100% of drug coated with $Eudragit^{TM}$ RS 100 membrane. The dissolution test was performed for two formulations. In case of conventional tablets, 2.5 mg of drug per a dose was administered orally into male Albino rabbit (2.0-2.3 kg of body weight) 3 times at intervals of 4 hours. In case of two sustained formulations, 7.5 mg of drug was administered once orally. Blood samples were withdrawn periodically after the administration, and the blood concentration was determined by HPLC. The conventional tablets showed very high peak-trough fluctuation between administered doses, but two sustained formulations showed less fluctuation. Formulation A with the loading dose showed the time to reach minimum effective concentration (MEC) i.e. the onset time was less than 20 min, while Formulation B had more than 1 hr of the onset time. Formulation A had the more constant plasma level than formulation B. However, formulation B had a time lag, so the plasma level was less than MEC for an initial period of 1 hr. In formulation A, the plasma level was maintained within the therapeutic window $(0.3-5\;{\mu}g/ml)$ for a long period. Formulation A was thought to be an ideal sustained-release formulation for ketorolac tromethamine oral delivery system.

  • PDF