Five individuals who meet the eligibility criteria will take part in this study. They will have a variety of assessments performed throughout the treatment period in order to evaluate both dermatomyositis and calcinosis severity and their potential response to fractional carbon dioxide and sodium thiosulfate treatment. A medical history will be taken and baseline assessments will be performed during the screening period. Serum creatinine kinase levels will be determined on this visit and repeated at the end of the study (week 20); these levels will be one measure of monitoring disease activity during the study. One calcinosis lesion will be treated, assessed, and followed. If a second calcinosis lesion is present, it will act as a control (not treated). Two weeks prior to the first treatment session, an optional (not required) skin biopsy of the target (treated) calcinosis lesion will be offered to the the first 3 patients ≥ 18 years of age to determine optimal fractional carbon dioxide laser settings that will be used for treatment. Area and durometer (a device that measures hardness) measurements and photographs of the calcinosis lesions will be performed at weeks 0,4,8,12,16,and 20. One x-ray of the control and one x-ray of the target calcinosis lesion will also be performed during the screening period and at week 20. Assessment of muscle strength, physical functioning, endurance, and range of motion, as well as myositis activity outside of the muscles will be performed during the screening period and at weeks 8 and 20. Myositis damage assessment will be performed at the screening period and at week 20. Questionnaires to assess physical functioning pertaining to activities of daily living and quality of life, as well as the quality of life related to skin disease and the calcinosis lesions will be completed during the screening period and at weeks 8 and 20. Treatment of the target calcinosis lesion with fractional carbon dioxide laser and topical sodium thiosulfate will occur on weeks 0,2,4,6,8,10,12,14,16,and 18. Each patient will receive a total of 8-10 treatments over a 6 month period. Assessments for any side effects from the treatment will be performed prior to each treatment session on weeks 0,2,4,6,8,10,12,14,16,18, and 20.