No Abstract Available.
X-Ray Film*

PURPOSE: X-ray film over responds to low-energy photons in relative photon beam dosimetry because its sensor is based on silver bromide crystals, which are high-Z molecules. This over-response becomes a significant problem in clinical photon beam dosimetry particularly in regions outside the penumbra. In intensity modulated radiation therapy (IMRT), the radiation field is characterized by multiple small fields and their outside-penumbra regions. Therefore, in order to use film dosimetry for IMRT, the nature the source of the over-response in its radiation field need to be known. This study is aimed to verify and possibly improve film dosimetry for IMRT. MATERIALS AND METHODS: Modulated beams were constructed by a combination of five or seven different static radiation fields using 6 MeV X-rays. In order to verify film dosimetry, we used X-ray film and an ion chamber were used to measure the dose profiles at various depths in a phantom. In addition, in order to reduce the over-response, 0.01 inch thick lead filters were placed on both sides of the film. RESULTS: The measured dose profiles showed a film over-response at the outside-penumbra and low dose regions. The error increased with depths and approached 15% at a maximum for the field size of 15X15 cm(2) at 10 cm depth. The use of filters reduced the error to 3%, but caused an under-response of the dose in a perpendicular set-up. CONCLUSIONS: This study demonstrated that film dosimetry for IMRT involves sources of error due to its over-response to low-energy photons. The use of filers can enhance the accuracy in film dosimetry for IMRT. In this regard, the use of optimal filter conditions is recommended.
Film Dosimetry* ; Photons ; Silver ; X-Ray Film

PURPOSE: To investigate the characteristics of the newly marketed, Insight dental X-ray film. MATERIALS AND METHODS: Kodak Ultraspeed (DF-58), E-speed, Agfa Dentus M2, and Kodak Insight (IP-21) films were radiographed using a Trophy intra-oral radiographic machine. 10 step exposure times were prepared and each step exposure was monitored using a FH 40G (ESM Eberline Instruments) dosimeter for each of the 4 types of intra-oral film. All films were manually processed and the radiographic densities at 6 sites of each processed film were measured, and the characteristic curves of each of the 4 types intra-oral films were created utilizing these dosimetric data and radiographic densities, based on ISO 5779. The film contrast, speed, and base plus fog density of Insight film were compared with those of the 3 other films examined in this experiment. RESULTS: E-speed film showed greatest average gradients followed by Insight film. E-speed and Ultraspeed film showed great average gradients at low density levels. Insight film showed the fastest speed followed by E-speed, Dentus M2 and Ultraspeed film. Dentus M2 film showed greatest base plus fog density level followed by Insight film. CONCLUSION: Kodak Insight film showed fastest film speed with comparable film contrast on characteristic curve.
Film Dosimetry ; Weather ; X-Ray Film*

Posterior cervical fusion is still the procedure of choice in the cases of spinal instability caused by flexion injuries. Halifax interlaminar clamp system can be used whenever posterior cervical fusion is to be performed. Thirty-one consecutive patients were treated with Halifax interlaminar clamp for cervical instability from Jan. 1991 to Jan. 1995. We followed up all of the cases for more than one year. All of the twenty-six mid-and low-cervical fixations showed immediate and long-term stability and there were no neurological complications. Two cases among the five C1-2 fixations were failed due to loosening of clamps. Fifteen cases of mid-and low-cervical fixations showed facet sclerosis and interbody fusion on the plain X-ray films after more than one year.
Humans ; Sclerosis ; X-Ray Film

BACKGROUND: Among various methods for measuring colon transit time, radio-opaque marker study is simple, reproducible and economical method. The commonly used marker, Sitzmarks (Konsyl Pharmaceuticals Inc. Texas) had limitation in its use due to expensiveness and difficulty in importation. We thought that the new domestic marker comparable to Sitzmarks is necessary and made a Kolomark (Korean colon marker)TM. The comparison of radio-opaqueness and the measurement of colon transit times by two markers were done. METHODS: In two 1000 ml beakers, 350 ml of rice-gruel, several chicken-bones and ten rings of Sitzmarks and KolomarkTM were mixed separately. Then, X-ray films of the two beakers were taken. The digital image file was analyzed by Image and the value of pixels were obtained. These were repeated five times. Colon transit times were measured in 60 healthy persons stratified by age, 30 by Sitzmarks and 30 by KolomarkTM. RESULTS: The mean value of pixel of KolomarkTM was much lower than that of Sitzmarks. The difference between background or beaker and KolomarkTM was much greater than that of Sitzmarks . There was no significant difference between colon transit time studied by Sitzmarks and KolomarkTM. CONCLUSION: KolomarkTM, a more radio-opaque and cheaper marker than Sitzmarks will be applied usefully for measuring colon transit time.
Colon* ; Humans ; X-Ray Film

BACKGROUND/AIMS: Colon transit time is a useful method for assessing colonic motor function and classifying the type of idiopathic chronic constipation. Among various methods, a radio-opaque marker study is a simple, reproducible and economical method. The commonly used marker, Sitzmarks(R)(Konsyl Pharmaceuticals Inc. Texas) had limitations in its use due to expensiveness and difficulty in importation. We thought that a new domestic marker comparable to Sitzmarks(R) was necessary and we developed Kolomark (Korean colon marker)(TM). The radio-opaqueness of Kolomark(TM) was compared to that of Sitzmarks(R). METHODS: In two 1000ml of beakers, 350ml of rice-gruel, several chicken-bones and ten rings of Sitzmarks(R) and Kolomark(TM) were mixed separately. Then, X-ray films of the two beakers were taken. The digital image file was analyzed by image(R), a medical image processing program, and the value of pixels were obtained. These were repeated five times. RESULTS: The mean value of pixel of Kolomark(TM) was much lower than that of Sitzmarks(R). The difference between background or beaker and Kolomark(TM) was much greater than that of Sitzmarks. CONCLUSION: Kolomark(TM), a Korean colon marker which is more radio-opaque and cheaper than Sitzmarks(R) is developed and further study is needed to prove its clinical usefulness.
Colon* ; Constipation ; X-Ray Film

If one can measure the actual angle of the bowing and rotation of a long bone three-dimensionally, it will be a great help in fracture reductions, operative treatments of the congenital snomalies, determination of the fusion angles in arthrodeses, and so on. We developed a computer program that gives us the actual bowing and rotation angle when we input the angles from the two X-ray films with known angle between them. We measured anteversion and neck-shaft angle of the femur, the amount of bowing and rotation in fracture model, and the fusion angles in arthrodeses. The angles calculated from the computer program were same as those from another X-ray that showed the actual angle taken by derotating the subject.
Arthrodesis ; Femur ; X-Ray Film

The use of high dose rate remote afterloading system for the treatment of intraluminal lesions necessitates the need for a more accurate of dose distributions around the high intensity brachytherapy sources, doses are often prescribed to a distance of few centimeters from the linear source, and in this range the dose distribution is very difficult to assess. Accurated and optimized dose calculation with stable numerical algorithms by PC level computer was required to treatment intraluminal lesions by high dose rate brachytherapy system. The exposure rate from sources was calculated with Sievert integral and dose rate in tissue was calculated with Meisberger equation. An algorithm for generating a treatment plan with optimized dose distribution was developed for high dose rate intraluminal radiotherapy. The treatment volume becomes the locus of the constrained target surface points that is the specified radial distance from the source dwelling positions. The treatment target volume may be alternately outlined on a x-ray film of the implant dummy sources. The routine used a linear programming formulism to compute which dwell time at each position to irradiate the constrained dose rate at the target surface points whiles minimizing the total volume integrated dose to the patient. The exposure rate and the dose distribution to be confirmed the result of calculation with algorithm were measured with film dosimetry, TLD and small size ion chambers.
Brachytherapy ; Film Dosimetry ; Humans ; Programming, Linear ; Radiotherapy ; X-Ray Film

PURPOSE: To compare the film density of Insight dental X-ray film (Eastman Kodak Co., Rochester, NY, USA) with that of Ektaspeed Plus film (Eastman Kodak) under manual and automatic processing conditions. MATERIALS AND METHODS: Insight and Ektaspeed Plus films were exposed at three different exposure conditions with an aluminum step wedge on the films under the three different exposure times. The exposed films were processed by both manual and automatic ways. The Base plus fog density and the optical density made by exposing step wedge were calculated using a digital densitometer (model 07-443, Victoreen Inc, Cleveland, Ohio, USA). The optical densities of the Insight and Ektaspeed film versus thickness of alumimun wedge at the same exposure time were plotted on the graphs. Statistical analyses were applied for comparing the optical densities of the two films. RESULTS: The film density of both Insight films and Ektaspeed Plus films under automatic processing condition was significantly higher over the manual processing. The film density of Insight films was significantly higher than that of Ektaspeed Plus films on both automatic and manual processing conditions. CONCLUSION: The radiation exposure time can be reduced when using Insight over Ektaspeed Plus film. To take the full advantage of reducing exposure time, Insight film should be processed automatically.
Aluminum ; Ohio ; Radiography ; Weather ; X-Ray Film*

PURPOSE: To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. MATERIALS AND METHODS: Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. RESULTS: As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. CONCLUSION: Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.
Fractals* ; Humans ; Mandible ; Radiography ; X-Ray Film