ABSTRACT
@#<b>Objective</b> To analyze the distribution features of the Bragg peak of carbon ion beams in materials using SRIM software, and to explore the use of computed tomography (CT) number to calculate the incident energy of carbon ion beams. <b>Methods</b> SRIM software was used to study the travel of carbon ion beams (100 to 300 MeV/u) in different equivalent materials, and analyze the effects of the incident energy of carbon ion beams and the type and thickness of equivalent materials on the depth of the Bragg peak of carbon ion beams. Origin 2017 was used to analyze the functional relationship between CT number and water-equivalent Bragg peak depth ratio (<i>Di</i>) through data fitting. <b>Results</b> The ratios of the Bragg peak depths in equivalent materials to that in water almost stayed constant with the increase in the incident energy of carbon ion beams. Through the functional relation between CT number and <i>D</i><sub><i>i</i></sub>, the Bragg peak depth of a carbon ion beam of a given energy in an equivalent material could be converted to the equivalent Bragg peak depth in water. <b>Conclusion</b> With the water-equivalent Bragg peak depth ratio <i>D</i><sub><i>i</i></sub> and CT number of different volume units of human tissues, the equivalent Bragg peak depth in water required for the Bragg peak to fall in the tumor can be accurately calculated, which can be used to reversely infer the needed incident energy of carbon ion beams.
ABSTRACT
Objective:To analyze clinical and histopathological features of cutaneous horns, and to explore their relationship.Methods:A total of 204 patients with cutaneous horns confirmed by clinical and histopathological examinations were collected from Department of Pathology, Shanghai Skin Disease Hospital between January 2014 and May 2020, and their clinical and histopathological data were retrospectively analyzed.Results:Among 204 patients, there were 88 males and 116 females with the age being 70.47±14.76 years and median ( P25, P75) course being 6 (6, 24) months. Cutaneous horns were solitary in 201 cases, and multiple in 3. There were a total of 207 cutaneous horns, including 163 (78.74%) located on the head, face and neck, 18 (8.70%) on the trunk and 26 (12.56%) on the extremities. According to histopathological conditions at the base of the cutaneous horns, 154 (74.40%) cutaneous horns were considered to arise from benign lesions (named as benign horns) , including viral warts ( n=129) , seborrheic keratosis ( n=15) , inverted follicular keratosis ( n=3) , trichilemmomas ( n=5) , pyogenic granuloma ( n=1) and calcifying epithelioma ( n=1) ; 40 (19.32%) were considered to arise from premalignant lesions (actinic keratosis) and named as premalignant horns; 13 (6.28%) were considered to arise from malignant lesions (named as malignant horns) , including Bowen′s disease ( n=5) and squamous cell carcinoma ( n=8) . The average ages of patients with premalignant and malignant horns were significantly higher than those of patients with benign horns ( H=4.05, 3.16, respectively, both P < 0.01) . The base width of the malignant horns was significantly higher than that of the premalignant and benign horns ( H=2.74, 3.49, P < 0.05, 0.01, respectively) , and there was no significant difference between the premalignant and benign horns ( H=0.73, P > 0.05) . The height to base width ratio was significantly lower in the premalignant and malignant horns than in the benign horns ( H=4.06, 3.72, respectively, both P < 0.01) . The incidence rate of basal erythema was significantly higher in the premalignant and malignant horns than that in the benign horns ( χ2=29.57, 6.23, P < 0.01, 0.05, respectively) , and bleeding and crusting occurred more frequently in the malignant horns compared with the benign horns ( χ2=4.89, P < 0.05) . Conclusions:The base of most cutaneous horns is benign, which mainly includes viral warts, and premalignant and malignant horns account for about a quarter. Male, older age, wide base, low ratio of the height to base width, basal erythema, history of bleeding and crusting can serve as clues to early recognition of malignant lesions at the base of cutaneous horns.