Lloyd J J
Regional Medical Physics Department, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, U.K.
Br J Dermatol. 2004 Jun;150(6):1162-6. doi: 10.1111/j.1365-2133.2004.05981.x.
Phototherapy units should regularly use hand-held ultraviolet (UV) meters to assess the output of treatment lamps, and these meters should be accurately calibrated. Several medical physics departments in the U.K. can calibrate UV meters traceable to national standards, but there is concern that there may be disagreement among departments. In particular, there may be difficulty in calibration for narrow-band UVB phototherapy lamps (TL-01).
To ascertain the level of agreement in UV meter calibration at expert centres in the U.K., and to survey methodology at these centres, consider sources of errors and to make recommendations on calibration methods.
The same UV meter with two detectors (for UVA and UVB) was calibrated by seven medical physics departments. A questionnaire on methods was also distributed and measured spectral outputs from each centre were examined.
The calibration factors for the meter varied by +/- 18% for the UVA detector and by +/- 60% for the UVB detector (2 standard deviations). Six centres performed calibration using a spectroradiometer and one centre used a reference meter method. The spectra of lamps used for calibration were similar. For the spectroradiometric methods there were some differences in methodology and instrumentation that may account for the differences in calibration factors.
UV meter calibration in the U.K. shows unacceptable variability, particularly for TL-01 lamps. An accuracy of around of +/- 10% would be clinically acceptable and should be technically achievable.
光疗设备应定期使用手持式紫外线（UV）计来评估治疗灯的输出，并且这些计应进行准确校准。英国的几个医学物理部门可以校准可追溯到国家标准的紫外线计，但人们担心各部门之间可能存在差异。特别是，窄带UVB光疗灯（TL - 01）的校准可能存在困难。
确定英国专家中心紫外线计校准的一致程度，调查这些中心的方法，考虑误差来源并就校准方法提出建议。
由七个医学物理部门对同一台带有两个探测器（用于UVA和UVB）的紫外线计进行校准。还分发了一份关于方法的问卷，并检查了每个中心测量的光谱输出。
该计的校准因子对于UVA探测器变化了±18%，对于UVB探测器变化了±60%（2个标准差）。六个中心使用光谱辐射计进行校准，一个中心使用参考计方法。用于校准的灯的光谱相似。对于光谱辐射计方法，在方法和仪器方面存在一些差异，这可能解释了校准因子的差异。
英国的紫外线计校准显示出不可接受的变异性，特别是对于TL - 01灯。约±10%的准确度在临床上是可接受的，并且在技术上应该是可以实现的。
