A dynamic infrared imaging-based diagnostic process for breast cancer.

BACKGROUND: Dynamic infrared (IR) imaging is an emerging functional imaging modality for the detection of breast cancer without evidence of optimal imaging and diagnostic application. PURPOSE: To evaluate dynamic IR imaging in breast cancer diagnostics by comparing a stepwise diagnostic scheme to digital mammography and postoperative histopathology. MATERIAL AND METHODS: Dynamic IR imaging of breasts was undertaken preoperatively with a long-wave quantum well (QWIP) and two mid-wave photovoltaic (PV) IR cameras in 10 cases (age 34-80 years) with breast cancer size 6-45 mm on mammography. Image stabilization, two-phase frequency analysis, and two image-processing algorithms were applied. RESULTS: Combining image processing with frequency analysis proved advantageous in detecting breast cancer. The IR imaging process recognized the cancer area independently of tissue density, cancer size, and cancer appearance on mammography. Compared to histopathology, all cancers yielded abnormal analysis results, including one case of ductal carcinoma in situ. Evidence of lymphatic invasion in postoperative histopathology, imaging with PV camera, and image processing with the Wiener filtering combination correlated with highest confidence between normal and cancer tissue measured by the calculated superiority value. CONCLUSION: Dynamic IR imaging with image-processing-guided frequency analysis is a promising modality for breast cancer detection and may not have the tissue-dependent limitations of mammography. Our results encourage further work on medical IR imaging and comparison to established breast-imaging modalities.

Dynamic infrared imaging in identification of breast cancer tissue with combined image processing and frequency analysis.

Five combinations of image-processing algorithms were applied to dynamic infrared (IR) images of six breast cancer patients preoperatively to establish optimal enhancement of cancer tissue before frequency analysis. mid-wave photovoltaic (PV) IR cameras with 320x254 and 640x512 pixels were used. The signal-to-noise ratio and the specificity for breast cancer were evaluated with the image-processing combinations from the image series of each patient. Before image processing and frequency analysis the effect of patient movement was minimized with a stabilization program developed and tested in the study by stabilizing image slices using surface markers set as measurement points on the skin of the imaged breast. A mathematical equation for superiority value was developed for comparison of the key ratios of the image-processing combinations. The ability of each combination to locate the mammography finding of breast cancer in each patient was compared. Our results show that data collected with a 640x512-pixel mid-wave PV camera applying image-processing methods optimizing signal-to-noise ratio, morphological image processing and linear image restoration before frequency analysis possess the greatest superiority value, showing the cancer area most clearly also in the match centre of the mammography estimation.

Imaging of breast cancer with mid- and long-wave infrared camera.

In this novel study the breasts of 15 women with palpable breast cancer were preoperatively imaged with three technically different infrared (IR) cameras - micro bolometer (MB), quantum well (QWIP) and photo voltaic (PV) - to compare their ability to differentiate breast cancer from normal tissue. The IR images were processed, the data for frequency analysis were collected from dynamic IR images by pixel-based analysis and from each image selectively windowed regional analysis was carried out, based on angiogenesis and nitric oxide production of cancer tissue causing vasomotor and cardiogenic frequency differences compared to normal tissue. Our results show that the GaAs QWIP camera and the InSb PV camera demonstrate the frequency difference between normal and cancerous breast tissue; the PV camera more clearly. With selected image processing operations more detailed frequency analyses could be applied to the suspicious area. The MB camera was not suitable for tissue differentiation, as the difference between noise and effective signal was unsatisfactory.

Cost accounting of radiological examinations. Cost analysis of radiological examinations of intermediate referral hospitals and general practice.

The purpose of this study was to analyse the cost structure of radiological procedures in the intermediary referral hospitals and general practice and to develop a cost accounting system for radiological examinations that takes into consideration all relevant cost factors and is suitable for management of radiology departments and regional planning of radiological resources. The material comprised 174,560 basic radiological examinations performed in 1991 at 5 intermediate referral hospitals and 13 public health centres in the Pirkanmaa Hospital District in Finland. All radiological departments in the hospitals were managed by a specialist in radiology. The radiology departments at the public health care centres operated on a self-referral basis by general practitioners. The data were extracted from examination lists, inventories and balance sheets; parts of the data were estimated or calculated. The radiological examinations were compiled according to the type of examination and equipment used: conventional, contrast medium, ultrasound, mammography and roentgen examinations with mobile equipment. The majority of the examinations (87%) comprised conventional radiography. For cost analysis the cost items were grouped into 5 cost factors: personnel, equipment, material, real estate and administration costs. The depreciation time used was 10 years for roentgen equipment, 5 years for ultrasound equipment and 5 to 10 years for other capital goods. An annual interest rate of 10% was applied. Standard average values based on a sample at 2 hospitals were used for the examination-specific radiologist time, radiographer time and material costs. Four cost accounting versions with varying allocation of the major cost items were designed. Two-way analysis of variance of the effect of different allocation methods on the costs and cost structure of the examination groups was performed. On the basis of the cost analysis a cost accounting program containing both monetary and nonmonetary variables was developed. In it the radiologist, radiographer and examination-specific equipment costs were allocated to the examinations applying estimated cost equivalents. Some minor cost items were replaced by a general cost factor (GCF). The program is suitable for internal cost accounting of radiological departments as well as regional planning. If more accurate cost information is required, cost assignment employing the actual consumption of the resources and applying the principles of activity-based cost accounting is recommended. As an application of the cost accounting formula the average costs of the radiological examinations were calculated. In conventional radiography the average proportion of the cost factors in the total material was: personnel costs 43%, equipment costs 26%, material costs 7%, real estate costs 11%, administration and overheads 14%. The average total costs including radiologist costs in the hospitals were (FIM): conventional roentgen examinations 188, contrast medium examinations 695, ultrasound 296, mammography 315, roentgen examinations with mobile equipment 1578. The average total costs without radiologist costs in the public health centres were (FIM): conventional roentgen examinations 107, contrast medium examinations 988, ultrasound 203, mammography 557. The average currency rate of exchange in 1991 was USD 1 = FIM 4.046. The following formula is proposed for calculating the cost of a radiological examination (or a group of examinations) performed with a certain piece of equipment during a period of time (e.g. 1 year): a2/ sigma ax*ax+ b2/ sigma bx*bx+ d1/d5*dx+ e1 + [(c1+ c2) + d4 + (e2 - e3) + f5 + g1+ g2+ i]/n.