Design method for light source, and light irradiation device

Abstract

The present invention provides a design method for a light source of a light irradiation device that is used during usage or storage of a photosensitive substance or when managing a patient who has been administered a photosensitive substance. A design method according to the present invention comprises: a step for obtaining an emission spectrum of a reference light source; a step for obtaining an emission spectrum of a light source to be evaluated; a step for obtaining an absorption coefficient of a photosensitive substance; and a step for using the absorption coefficient and the obtained light source spectra to find the ratio of absorption energy in the photosensitive substance caused by irradiation from the reference light source to absorption energy in the photosensitive substance caused by irradiation from the light source to be evaluated, and using said ratio to design a light source.

Description

Light source design method and light irradiation device

[0001] The present invention relates to a method for designing a light source, and more particularly to a method for designing a light source for a light irradiation device used when using or storing a photosensitive substance or when managing a patient who has been administered a photosensitive substance, and to a light irradiation device.

[0002] Photodynamic therapy (hereinafter referred to as "PDT") is a treatment method in which laser light or the like is irradiated onto photosensitive substances accumulated in the affected area, and it is a treatment method that kills tumors by irradiating them with light of an excitation wavelength specific to the photosensitive substance.

[0003] In PDT, first, photosensitive substances accumulated (residual) in tumor tissue are irradiated with illumination light such as laser light. The photosensitive substance enters an excited state (a high-energy, unstable state) due to the absorption of energy from the light irradiation. This unstable state does not last long, and the photosensitive substance transitions to its original stable energy state, the ground state. At this time, excess energy is released in the form of light energy called phosphorescence or fluorescence. When this phosphorescence or fluorescence is received by oxygen present in the vicinity, the oxygen transitions to an excited state called singlet oxygen. This singlet oxygen then causes the degeneration and necrosis of tumor tissue.

[0004] The administered photosensitizer may be present in tissues other than tumor tissue, and singlet oxygen also affects normal tissue. This singlet oxygen causes cell necrosis and damage, resulting in photosensitivity reactions. Therefore, the biggest problem with PDT is that exposure to high-intensity light, such as sunlight, after administration of the photosensitizer can result in photosensitivity reactions such as erythema, blisters, and pigmentation of the skin. Therefore, patients must be kept under low-intensity light (e.g., 500 lux or less) for a certain period of time after administration of the photosensitizer, and must be placed under a different light level than other patients. Adding such a special environment to the management of patients with diverse medical conditions increases the burden on medical professionals. To remove this light-shielding regimen, a negative photosensitivity test is required. For example, when talaporfin sodium is used as the photosensitizer in PDT, the photosensitivity test involves exposing the dorsum of the palm to direct sunlight at 20,000 lux or more for 5 minutes to assess the presence or absence of photosensitivity reactions.

[0005] As an alternative method, Patent Document 1 discloses a skin residual drug measuring device and a skin residual drug measuring device that measure an estimated concentration of a photosensitizer remaining in the skin tissue of a living body.

[0006] Japanese Patent Publication No. 2018-64720

[0007] As mentioned above, photosensitivity testing requires a specific level of illumination, so it must be performed on a sunny day. Therefore, if bad weather persists, the test cannot be performed, delaying the lifting of light-blocking measures, and in some cases delaying the patient's discharge. Similarly, light-blocking measures require maintaining low illumination levels. In this case, patients may be forced to live under conditions of lower illumination than necessary to avoid risk.

[0008] Therefore, one aspect of the present invention has been made in consideration of the above-mentioned problems, and its object is to provide a method for designing a light source that can replace sunlight and can be used in a photosensitivity test performed when determining whether to stop light protection during light protection management for patients undergoing PDT.

[0009] In another aspect of the present invention, an object is to provide a method for designing a light source that reduces the risk of photosensitivity in patients undergoing PDT treatment when they are kept under shading.

[0010] In another aspect of the present invention, it is an object to provide a method for designing a light source that can minimize unintended excitation of drugs associated with PDT treatment.

[0011] The singlet oxygen that causes photosensitive reactions is produced by phosphorescence and fluorescence from photosensitizers. When a photosensitizer is excited by irradiation with light having the absorption wavelength spectrum of the photosensitizer, the amount of phosphorescence and fluorescence emitted upon transition to the ground state is thought to be proportional to the magnitude of the absorption energy of the photosensitizer. Therefore, the reaction amount of photosensitive reactions is thought to be proportional to the absorption energy of the photosensitizer, and therefore, the absorption energy of the photosensitizer can be said to be one of the indicators of the reaction amount of photosensitive reactions. The inventors focused on this point and completed the present invention.

[0012] In order to solve the above-mentioned problems, a method for designing a light source according to one aspect of the present invention is a method for designing a light source for a light irradiation device used when using or storing a photosensitive substance or when managing a patient who has been administered a photosensitive substance, and includes the steps of: (a1) obtaining a reference light source spectrum, which is the emission spectrum of a reference light source; (a2) obtaining an evaluation light source spectrum, which is the emission spectrum of a light source to be evaluated; (a3) ​​obtaining an absorption coefficient of the photosensitive substance; and (a4) using the absorption coefficient, the reference light source spectrum, and the evaluation light source spectrum, determining a ratio of the evaluation light source absorption energy, which is the absorption energy in the photosensitive substance when irradiated with the reference light source, to the evaluation light source absorption energy, which is the absorption energy in the photosensitive substance when irradiated with the reference light source, and using the ratio to design a light source.

[0013] According to a method for designing a light source according to one aspect of the present invention, it is possible to design a light source that can replace sunlight and be used in a photosensitivity test, thereby making it possible to conduct a photosensitivity test regardless of weather and time.

[0014] Furthermore, according to a method for designing a light source according to another aspect of the present invention, it is possible to design lighting that is suitable for use in a light-shielded, controlled environment after photodynamic therapy and that is less likely to cause photosensitivity reactions, thereby providing patients with a comfortable environment with a low risk of developing photosensitivity and reducing the management burden on medical professionals.

[0015] Furthermore, according to another aspect of the present invention, a method for designing a light source makes it possible to design a light source and device that can minimize unnecessary drug excitation caused by drug adjustments during photodynamic therapy or by shadowless lamps or endoscopic light sources used in surgery, thereby enabling more accurate and controlled photodynamic therapy.

[0016] 1 is a diagram showing the spectrum of relative luminous efficiency. 2 is a diagram showing the irradiation spectrum of sunlight. 3 is a diagram showing the molar absorption coefficient of talaporfin sodium in the co-presence of albumin. 4 is a diagram showing the measurement results of the emission spectrum of a white LED. 5 is a diagram showing the measurement results of the emission spectrum of a sunlight LED. 6 is a diagram showing an example of the configuration of a photosensitivity test device configured using an LED light source for photosensitivity tests. 7 is a diagram showing the measurement results of the emission spectrum of a blue LED. 8 is a diagram showing the measurement results of the emission spectrum of a green LED. 9 is a diagram showing the measurement results of the emission spectrum of a red LED. 10 is a diagram showing the measurement results of the emission spectrum of an RGB-LED (color temperature 6000K). 11 is a diagram showing the measurement results of the emission spectrum of an RGB-LED (color temperature 3500K). 12 is a diagram showing an example of the configuration of a lighting device for use under shading control using an RGB-LED. 13 is a diagram showing the measurement results of the emission spectrum of a daylight fluorescent lamp. 14 is a diagram showing the measurement results of the emission spectrum of an incandescent fluorescent lamp.

[0017] [Embodiment 1] Hereinafter, one embodiment of a method for designing a light source for a light irradiation device used during use or storage of a photosensitizer or during management of a patient administered a photosensitizer according to the present invention will be described. Hereinafter, as an example of a method for designing a light source, a case where an LED is used as the light source to be evaluated will be described, but this embodiment is not limited thereto. Furthermore, where appropriate, a case where the photosensitizer is talaporfin sodium will be described as an example, but this embodiment is not limited thereto.

[0018] In this specification, "use in the management of patients administered with a photosensitizer" means use in the light-protection management of patients undergoing PDT treatment, and use in the implementation of a photosensitivity test to determine whether or not the light-protection management can be discontinued. In this embodiment, a method for designing a light source of a light irradiation device for use in the implementation of a photosensitivity test will be described.

[0019] In this specification, "designing a light source" means (i) determining the light source to be used and determining the intensity (illuminance, drive current value, etc.) required when using that light source, or (ii) determining the intensity required for a certain light source when using that light source.

[0020] Furthermore, in this specification, the terms "irradiation spectrum" and "emission spectrum" are used interchangeably.

[0021] The method for designing a light source for a light irradiation device used in conducting a photosensitivity test in this embodiment includes the steps of: (a1) obtaining an emission spectrum of a reference light source; (a2) obtaining an emission spectrum of a light source to be evaluated; (a3) ​​obtaining an absorption coefficient of a photosensitizer; and (a4) using the obtained emission spectra and absorption coefficients to determine the ratio of the absorbed energy of the photosensitizer when irradiated with the reference light source to the absorbed energy of the photosensitizer when irradiated with the light source to be evaluated, and evaluating the light source to be evaluated using this ratio. Note that there is no restriction on the order of steps (a1) to (a3) ​​as long as they are performed before step (a4).

[0022] (1. Step (a1)) In step (a1), an emission spectrum of a reference light source is obtained. In this embodiment, an irradiation spectrum of sunlight that provides the illuminance required for the photosensitivity test is obtained as the emission spectrum of the reference light source. As one aspect, a case where the illuminance is 20,000 lux, i.e., a case where the reference light source is sunlight with an illuminance of 20,000 lux, will be described as an example.

[0023] Generally, illuminance can be calculated using the irradiance spectrum, which is the wavelength distribution of the irradiance of a light source, and luminosity. The luminosity may be calculated using a relative luminosity where the maximum value is normalized to 1. When using the relative luminosity, the illuminance L (lux (= lm / m ２ )) is expressed as in equation (1) using the irradiance spectrum P(λ) and the relative luminous efficiency V(λ). Here, K is a constant, K = 683 (lm / W). λ represents wavelength. The luminous efficiency and relative luminous efficiency values ​​are defined as international standards by the International Commission on Illumination (CIE), but may be appropriately selected depending on the purpose. In the calculations, formulas, and explanations herein, when the irradiance spectrum P(λ) is used, it means that the irradiance for each wavelength in the irradiance spectrum P(λ) is used.

[0024] The relative luminous efficiency exhibits a distribution as shown in FIG. 1. As shown in FIG. 1, the relative luminous efficiency V(λ) is nearly zero in the range of 400 nm or less and in the range of 700 nm or more. Therefore, while the calculation of formula (1) essentially involves integration over the entire wavelength range, it is sufficient to perform the calculation within the range of 400 nm to 700 nm. Note that the wavelength range used for the calculation is not limited to the lower and upper limits as long as it includes the range of 400 nm to 700 nm. For example, it may be a range of 350 nm to 700 nm. Furthermore, in actual calculations, the relative luminous efficiency and irradiance at each wavelength are multiplied for each unit wavelength (e.g., 1 nm) within the wavelength range to be calculated (e.g., 400 nm to 700 nm), and the resulting values ​​are integrated. This is then multiplied by a constant K to calculate the illuminance L.

[0025] According to equation (1), a certain irradiation spectrum P １ The irradiance of each wavelength at (λ) is multiplied by α to obtain the irradiance spectrum P α When the illuminance is calculated from equation (1) using (λ), the resulting illuminance L α Is, P １ (λ) Illuminance L obtained using １ Therefore, in step (a1), the reference spectrum of sunlight is P' ｓｕｎ(λ), the sunlight irradiance spectrum that gives an illuminance of 20,000 lux is P ｓｕｎ (λ), the reference spectrum of sunlight P' ｓｕｎ The spectrum obtained by simply multiplying the irradiance of each wavelength at (λ) by α is P ｓｕｎ The coefficient α for (λ) is calculated as the reference spectrum P′ of sunlight. ｓｕｎ (λ) may be, for example, a spectrum defined in ASTM G173-03 or ASTM AM1.5, or may be an actual value obtained by measuring in advance using a spectrophotometer or the like. When measuring sunlight using a spectrophotometer, it is sufficient to measure, for example, when the illuminance measured on the illuminometer is 20,000 lux or more on a clear day, approximately one hour after noon. When using the reference spectrum of ASTM G173-03, the illuminance of this reference spectrum is approximately 115,604 lux according to equation (1). In this case, α is 0.1730 (= 20,000 / 115,604). An example of the sunlight irradiation spectrum obtained using this value of α is shown in Figure 2.

[0026] (2. Step (a2)) In step (a2), the emission spectrum of the light source to be evaluated is obtained. The emission spectrum of the light source to be evaluated is intended to be the emission spectrum when the light source to be evaluated is irradiated at an arbitrary current value. In this embodiment, an LED is used as the light source to be evaluated, so the emission spectrum of the light source to be evaluated can be the emission spectrum when driven with a current within the range of the absolute maximum rated current of the LED element. In this specification, the current value when the emission spectrum of the light source to be evaluated is obtained is referred to as the "current value at evaluation". In the following, the emission spectrum of the light source to be evaluated at the current value at evaluation is referred to as P' ＬＥＤ Let (λ).

[0027] Emission spectrum P' ＬＥＤ (λ) may be measured using a spectrophotometer, etc. For example, the emission spectrum P′ of a white LED (Nichia Chemical, NSDW570GS-K1 (b4p11)) measured using a spectrophotometer as an example of the light source to be evaluated is ＬＥＤ (λ) is shown in FIG.

[0028] (3. Step (a3)) In step (a3), the molar absorption coefficient ε(λ) of the photosensitizer is obtained. The method for obtaining the molar absorption coefficient ε(λ) of the photosensitizer is not particularly limited, and it may be obtained by measurement using a spectrophotometer. When measuring using a spectrophotometer, a person skilled in the art can measure the molar absorption coefficient ε(λ) of the photosensitizer using an existing spectrophotometer without undue burden.

[0029] In vivo, the molar absorption coefficient ε(λ) of a photosensitizer may be slightly different from the value in the absence of a biological substance, such as albumin, due to the presence of such a biological substance. Therefore, in one aspect of this embodiment, the molar absorption coefficient ε(λ) is preferably a value measured in the presence of a biological substance, such as albumin.

[0030] The method for obtaining the emission spectra of the reference light source and the light source to be evaluated, and the molar absorption coefficient of the photosensitive substance is not particularly limited, and may be obtained by measurement using a spectrophotometer or spectrophotometer, by obtaining results of measurements already taken by others, by calculation from other measurements, or by using other publicly known information.

[0031] (4. Step (a4)) In step (a4), first, the ratio of the absorbed energy in the photosensitive substance when irradiated with the light source to be evaluated (evaluated light source absorbed energy) to the absorbed energy in the photosensitive substance when irradiated with the reference light source (reference light source absorbed energy) is determined. Next, the light source is designed using this ratio. In this specification, "absorbed energy" refers to the absorbed energy of the photosensitive substance per unit concentration, unit volume, and unit time. In this embodiment, an example will be described in which the absorbed energy is determined when irradiated with the light source to be evaluated and the reference light source, and the ratio is calculated from the obtained absorbed energy values, but the calculation method is not limited to this as long as a value equivalent to the ratio can be obtained.

[0032] Specifically, the sunlight irradiation spectrum P ｓｕｎ The absorbed energy in the photosensitizer upon irradiation with (λ) is E ｓｕｎ and the emission spectrum P' of the light source to be evaluated is ＬＥＤThe absorbed energy due to irradiation at (λ) is E' ＬＥＤ The ratio E ｓｕｎ / E' ＬＥＤ Then, using this ratio, the absorbed energy E ｓｕｎ We design a light source that provides an absorbed energy equal to or greater than this ratio E ｓｕｎ / E' ＬＥＤ is called the absorbed energy ratio and is represented by β.

[0033] The absorbed energy E of a photosensitizer when irradiated with an irradiation spectrum P(λ) can be calculated using the molar absorption coefficient ε(λ) of the photosensitizer as shown in formula (2). This is because the irradiation spectrum P(λ) represents the irradiance at each wavelength, and the product of the irradiance and the molar absorption coefficient ε(λ) at each wavelength is the contribution to a photosensitivity reaction at that wavelength, and integrating this over the entire wavelength range is thought to give the total amount of contribution to a photosensitivity reaction. In the actual calculation of formula (2), the absorbed energy E can be calculated by multiplying the irradiance of the irradiation spectrum P(λ) at each unit wavelength (for example, every 1 nm) within a predetermined wavelength range by the molar absorption coefficient ε(λ), and integrating the obtained values.

[0034] Regarding the molar absorption coefficient ε(λ) used to calculate the absorbed energy E, if the molar absorption coefficient ε(λ) is measured in the presence of a biological substance, the absorption by the biological substance will also be included in the measured value. Therefore, when using the value of the molar absorption coefficient ε(λ) measured in the presence of a biological substance in equation (2), it is preferable to calculate the absorbed energy E within a range that is not affected by absorption by the biological substance or a range in which the effect is negligible and in which the absorbed energy of the photosensitizer can be appropriately calculated, for example, a range that includes all of the main peaks of the molar absorption coefficient of the photosensitizer. The effect of absorption by the biological substance on the measured value can be easily determined by comparing it with a measured value in the absence of the biological substance.

[0035] According to equation (2), a certain irradiation spectrum P １ The irradiance of each wavelength at (λ) is multiplied by α to obtain the irradiance spectrum P αWhen the absorbed energy is calculated from equation (2) using (λ), the obtained absorbed energy E α Is, P １ The absorbed energy E obtained using (λ) １ Therefore, as shown in the following formula (3), the absorbed energy E ｓｕｎ Absorbed energy E' ＬＥＤ By dividing by this, the absorbed energy E' ＬＥＤ Absorbed energy E ｓｕｎ Find the ratio.

[0036] The obtained ratio is the emission spectrum P' of the light source to be evaluated. ＬＥＤ By multiplying by (λ), the absorbed energy E ｓｕｎ The emission spectrum P of the light source to be evaluated that will give the same absorbed energy (the same contribution to photosensitivity reaction) as ＬＥＤ (λ) can be obtained.

[0037] In the case of LEDs, the radiation intensity is roughly proportional to the current value within the rated current value, so the value obtained by multiplying the evaluation current value of the light source to be evaluated by β is used as the absorbed energy E ｓｕｎ This can be considered as the drive current value (hereinafter referred to as the "required current value") required to provide the same absorbed energy as the current value during evaluation. In other words, by calculating the absorbed energy ratio β at the evaluation current value, the drive current value required for use as a light source for photosensitivity testing can be determined. Furthermore, the step of confirming that the desired emission spectrum is achieved by measuring the emission spectrum and illuminance of the light source to be evaluated at the determined required current value may be included, or the step of (readjusting) the light source design by recalculating β may be included. The smaller the required current value, the more suitable the light source is for photosensitivity testing.

[0038] Another indicator for determining a light source for photosensitivity testing is whether the required current value is within the absolute maximum rated current of the light source. For example, it is generally considered preferable to use an LED at 60 to 80% of its absolute maximum rated current. Therefore, the suitability of a light source for use in photosensitivity testing can be determined depending on whether the required current value is within the absolute maximum rated current of the light source. The criteria for selecting a light source can be set appropriately, taking into account the characteristics of the light source, etc.

[0039] Furthermore, when multiple light sources are used as candidate light sources and the absorbed energy ratio β is calculated for each of them by performing the above steps (a2) and (a4), for example, the light source with the lowest required current value within the absolute maximum rated current can be selected as the light source for the photosensitivity test. This allows a light source with lower power consumption to be selected. Furthermore, the greater the difference between the required current value and the absolute maximum rated current, the more likely it is that irradiation will be performed at a current value greater than the required current value. Therefore, the required current value is preferably 95% or less of the absolute maximum rated current of the light source, more preferably 90% or less, even more preferably 85% or less, and particularly preferably 80% or less.

[0040] The absorption coefficient of a photosensitizer may have one or more peaks that differ depending on the photosensitizer. For example, in the case of talaporfin sodium in the presence of albumin, absorption peaks exist near 410 nm, 510 nm, and 660 nm. Therefore, when the energy efficiency is the same, a light source that contains more spectral components near these peak wavelengths is expected to require a smaller current. Therefore, it is preferable that the light source to be evaluated includes a light source that contains more spectral components near the peak wavelength of the absorption coefficient.

[0041] (5. Step (a5)) In one aspect of this embodiment, the absorption energy E ｓｕｎThe illuminance thus obtained may be referred to as the required illuminance L. ＬＥＤ It should be noted that step (a5) may be performed together with step (a4). By calculating the required illuminance through step (a5), a relatively easily measurable illuminance can be used as a standard when calibrating the light source when designing and using a fixture using the light source to be evaluated.

[0042] Required illuminance L ＬＥＤ As a method for calculating P obtained by the above formula (3), for example, ＬＥＤ (λ) and use this as P(λ) in the above formula (1) to calculate the illuminance from formula (1). The illuminance obtained in this way is the required illuminance L ＬＥＤ This becomes:

[0043] Furthermore, according to equations (1) and (3), P' ＬＥＤ (λ) is P(λ) in the above formula (1), and P' ＬＥＤ The required illuminance L can also be obtained by multiplying this by β. ＬＥＤ can be obtained.

[0044] As described above, by carrying out steps (a1) to (a4) or steps (a1) to (a5), it is possible to design a light source that can be used in photosensitivity testing of photosensitive substances, i.e., a type of light source and a necessary irradiation intensity (current value, illuminance, etc.) that will contribute to a photosensitivity reaction equal to or greater than that of sunlight at 20,000 lux. When the emission spectrum of the designed light source is obtained and the absorbed energy ratio β is calculated, E' ＬＥＤ is E ｓｕｎ Since it is equal to or greater than ｓｕｎ / E' ＬＥＤ ) is 1 or less than 1.

[0045] Furthermore, the above method makes it possible to determine the irradiation conditions for any light source that will cause the same contribution to photosensitivity reaction as irradiation with 20,000 lux sunlight. Therefore, by performing the above method using a light source that does not contain wavelengths in the ultraviolet region, which have adverse effects on the skin, as a candidate light source, it is possible to determine the irradiation conditions that can be used in photosensitivity testing for that light source. This makes it possible to conduct photosensitivity testing using a light source that does not contain wavelengths in the ultraviolet region.

[0046] (6. Specific Embodiments) The following provides a specific explanation of an embodiment using talaporfin sodium as the photosensitizer. In the case of PDT using talaporfin sodium as the photosensitizer, the minimum illuminance required for photosensitivity testing is 20,000 lux. This section also describes an example in which a white LED (Nichia Chemical, NSDW570GS-K1 (b4p11)) and a sunlight LED (Toyoda Gosei, ENB01-NHSD7-F1 (P3H5)) are used as the light source to be evaluated. A white LED is expected to contain a component corresponding to the maximum wavelength in the visible light region of the absorption coefficient of the sensitizer. The sunlight LED is intended to be an LED with a spectral waveform similar to that of sunlight.

[0047] The lower limit of the wavelength range used in each step is set to 350 nm for the following reasons. First, according to information on the Japan Meteorological Agency's website (https: / / www.data.jma.go.jp / gmd / env / uvhp / 3-40uv.html), UV-B (280-315 nm) accounts for approximately 0.1% of the total solar radiation irradiation energy. Therefore, the UV-B range is negligible in the calculations of this embodiment. Furthermore, as shown in FIG. 2 , the short-wavelength component of the solar radiation irradiation spectrum drops sharply below 350 nm. Furthermore, the molar absorption coefficient ε(λ) of talaporfin sodium measured in advance using a spectrophotometer with albumin alone and in an albumin buffer solution showed that in the albumin buffer solution, a peak due to albumin (absorption that does not contribute to photosensitivity reactions) was present below 300 nm, with its base extending beyond 300 nm. Therefore, to eliminate the influence of albumin, the lower limit of the wavelength range used in the calculation is set to 350 nm.

[0048] As shown in FIG. 1, the relative luminous efficiency V(λ) becomes almost zero at wavelengths of 700 nm or more, so the upper limit of the wavelength range used in each step is set to 700 nm.

[0049] The reference spectrum of sunlight P' defined in ASTM G173-03 ｓｕｎ (λ) is substituted into equation (1) as P(λ) to obtain P' ｓｕｎ Calculate the illuminance L at (λ) and then calculate the sunlight irradiation spectrum P where L = 20,000 lux. ｓｕｎ The calculation in equation (1) is performed by multiplying the relative luminosity and radiant intensity at each 1 nm wavelength and integrating the values ​​obtained in the range of 350 nm to 700 nm.

[0050] Irradiation spectrum P ｓｕｎ The absorbed energy E of talaporfin sodium per unit concentration, unit volume, and unit time when irradiated with sunlight (λ) ｓｕｎ is the molar absorption coefficient ε(λ) of talaporfin sodium and P ｓｕｎThe molar absorption coefficient ε(λ) is calculated from equation (2) using (λ). Here, the molar absorption coefficient ε(λ) of talaporfin sodium was obtained by measuring it in advance using a spectrophotometer in an albumin buffer solution. The molar absorption coefficient ε(λ) of talaporfin sodium in an albumin buffer solution is shown in Figure 3. In the calculation of equation (2), the molar absorption coefficient at each 1 nm wavelength is multiplied by the irradiance and the resulting values ​​in the range of 350 nm to 700 nm are integrated.

[0051] From the above, the absorbed energy E of talaporfin sodium under sunlight with an illuminance of 20,000 lux is ｓｕｎ The calculation results are as follows: ｓｕｎ =115978673.6 [W / (M・m ３ ) ].

[0052] The emission spectra of the white LED and sunlight LED, which are the light sources to be evaluated, were measured using a spectrophotometer at current values ​​of approximately 20 mA and approximately 95 mA, respectively. The obtained emission spectra are shown in Figure 4 (white LED) and Figure 5 (sunlight LED), respectively. Using these emission spectra, the absorbed energy E ｓｕｎ Similarly, the absorbed energy E' by irradiation with these emission spectra ＬＥＤ Ask for.

[0053] The obtained absorbed energy E' ＬＥＤ and the absorbed energy E by irradiation with sunlight of 20,000 lux ｓｕｎ The absorption energy ratio β was calculated from the above equation and was found to be as follows: White LED: β=3.398 Sunlight LED: β=0.7780 The emission spectra P′ shown in FIGS. 4 and 5 are respectively ＬＥＤ The irradiance at (λ) is multiplied by the corresponding β to obtain the absorbed energy E ｓｕｎ The emission spectrum P of each light source that gives the same absorption energy as ＬＥＤ (λ) is obtained.

[0054] White LED P ＬＥＤ Using (λ), the emission spectrum P ＬＥＤ The required illuminance L of the white LED when (λ)ＬＥＤ The result was as follows: L ＬＥＤ =83914 [lux] This means that when this white LED is used, with an illuminance of 83914 [lux], it can be used as an alternative light source for photosensitivity testing under sunlight conditions of 20,000 lux.

[0055] Similarly, the P of solar LED ＬＥＤ Using (λ), the emission spectrum P ＬＥＤ The required illuminance L of the sunlight LED when (λ) ＬＥＤ The result was as follows: L ＬＥＤ =34837 [lux] This means that when this sunlight LED is used, it can be used as an alternative light source for photosensitivity testing under sunlight conditions of 20000 lux, provided that the illuminance is 34837 [lux].

[0056] The current value of the white LED used during evaluation was approximately 20 mA (absolute maximum rated current: 80 mA), so the drive current value (required current value) required to obtain an illuminance of 83,914 lux was calculated by multiplying 20 mA by β = 3.398, to obtain approximately 68 mA, which is approximately 85% of the absolute maximum rated current.

[0057] Similarly, the current value during evaluation of the sunlight LED used was approximately 95 mA (absolute maximum rated current: 100 mA), so the drive current value (required current value) required to obtain an illuminance of 34,837 lux was calculated by multiplying 95 mA by β = 0.7780, to obtain approximately 74 mA, which is approximately 74% of the absolute maximum rated current.

[0058] From the above, it can be seen that the white LED requires a smaller drive current, but the drive current required for the white LED exceeds 60-80% of the absolute maximum rated current. Therefore, if the only light sources to be evaluated are the two LEDs mentioned above, the sunlight LED can be selected based on the evaluation results, and the required drive current can be designed. It is also possible to evaluate other light sources using the same procedure, and if one has a higher rating than the sunlight LED, then that light source can be selected.

[0059] [Embodiment 2] In the first embodiment, so-called white LEDs and sunlight LEDs having spectral components across almost the entire visible light range were used as the LED light source, but it is also possible to use a monochromatic LED light source having a central wavelength that coincides with the peak of the absorption coefficient of the photosensitizer. Similarly, the following description will be given using talaporfin sodium as an example of a photosensitizer.

[0060] The absorption coefficient of talaporfin sodium has three peaks, near 410 nm, near 510 nm, and near 660 nm. Monochromatic LED light sources with peaks near 410 nm, near 510 nm, or near 660 nm include, for example, a blue LED (OptoSupply, OSV6YL5111A), a green LED (OptoSupply, OSG59L5B61Y), and a red LED (OptoSupply, OSR7XNE1E1E) as candidate light sources for evaluation. Figures 7 to 9 show the measurement results of the emission spectra at each evaluation current value.

[0061] When each step of the first embodiment is carried out using these emission spectra, the results shown in Table 1 are obtained.

[0062]

[0063] As shown in Table 1, in the comparison of the three monochromatic LEDs used this time, the required illuminance L ＬＥＤ In order to obtain the required illuminance L using a red LED, a drive current value greater than the absolute maximum rated current is required, so it was evaluated as unusable (×). ＬＥＤ However, a relatively large current of 117 mA or more is required, which is not efficient, so the evaluation was given as acceptable (○). ＬＥＤ To obtain this, the required drive current is less than the absolute maximum rated current, and the difference is large. Furthermore, the required drive current is only 0.93 mA, which is extremely small. From the above, it can be expected that blue LEDs will operate for long periods of time even when powered by batteries. Therefore, using blue LEDs is the most advantageous in terms of efficiency, and the evaluation was given an excellent (◎).

[0064] [Embodiment 3] The light source determined using the light source design method in embodiments 1 and 2 can be used to replace a photosensitivity test using direct sunlight under any conditions.

[0065] For example, a photosensitivity test involving exposure to 20,000 lux of direct sunlight for five minutes can be substituted by irradiating the LED with a drive current of 74 mA (equivalent to 34,837 lux) for five minutes when using the sunlight LED (Toyoda Gosei, ENB01-NHSD7-F1(P3H5)). Similarly, when using the blue LED (OptoSupply, OSV6YL5111A), this can be substituted by irradiating the LED with a drive current of 0.93 mA (equivalent to 192 lux) for five minutes.

[0066] When using the above blue LED, in order to obtain the same absorbed energy as that of talaporfin sodium in sunlight with an illuminance of 20,000 lux, the drive current value is set to 0.93 mA (equivalent to 192 lux). However, by doubling this to 1.86 mA (equivalent to 384 lux) or even tripling this to 2.79 mA (equivalent to 576 lux), the exposure time can be shortened to 2 minutes 30 seconds and 1 minute 40 seconds, respectively. This is because the total absorbed energy is expressed as (absorbed energy per unit time (second)) x exposure time (seconds), and takes advantage of the fact that if the total absorbed energy is the same, the effect on photosensitivity reactions will be the same.

[0067] As mentioned above, when using LEDs, it is recommended to use them at 60 to 80% of the absolute maximum rated current. By using two or three light sources, rather than just one, it is possible to achieve illumination equivalent to 384 lux or 576 lux, thereby achieving the desired illuminance without exceeding the absolute maximum rated current.

[0068] In this embodiment, a photosensitivity test device using a light source determined by the light source design method in the first and second embodiments will be described with reference to FIG.

[0069] Fig. 6 is a diagram showing an example of the configuration of a photosensitivity test device using an LED. As shown in Fig. 6, the photosensitivity test device 100 is composed of an LED 1, which is a light source that irradiates a living body with light, a constant current source 2 that controls the current value of the LED 1 to maintain a constant irradiation output, a control unit 3 that instructs the current value command value, a display unit 4 that displays control information from the control unit 3, and a power supply 5. In this embodiment, the LED 1 is the blue LED used in embodiment 2.

[0070] Next, an example of the operation of the photosensitivity test device 100 will be described. For example, when replacing a photosensitivity test that involves five minutes of exposure to 20,000 lux of direct sunlight, the control unit 3 sends a current command value equivalent to 192 lux to the constant current source 2 based on input from the tester. The control unit 3 also starts irradiation with the LED 1 and simultaneously measures the five-minute period. While irradiation with the LED 1 is in progress, the display unit 4 displays information indicating that irradiation is in progress (e.g., "irradiation in progress") or information indicating the elapsed time since the start of irradiation (e.g., "irradiation time: xx minutes yy seconds") based on control information from the control unit 3. For example, upon completion of five minutes of irradiation, the control unit 3 sends a current command value of zero to the constant current source 2 to terminate irradiation, and causes the display unit 4 to display "irradiation completed" or "irradiation time: 5 minutes 00 seconds" to inform the tester that irradiation is complete.

[0071] [Embodiment 4] In Embodiments 1 and 2, a design method for a light source for photosensitivity testing was described based on the idea that a light source containing as many wavelength components as possible at the peak of the absorption coefficient of the photosensitizer is desirable. From the opposite perspective, lighting less likely to induce photosensitivity reactions can be constructed by configuring lighting with a light source having a peak wavelength that does not overlap with the peak wavelength component of the absorption coefficient of the photosensitizer. Specifically, in Embodiments 1 and 2, the illuminance of a light source for photosensitivity testing was determined to have the same effect on photosensitivity reactions as exposure to 20,000 lux of sunlight. In contrast, in this embodiment, the light source that has the greatest effect on photosensitivity reactions among common lighting sources such as sunlight, fluorescent lamps, and LEDs is selected as a standard for use under light-shielded control of patients after administration of a photosensitizer, and the illuminance of a light source that has the same effect as the illuminance of other light sources is determined.

[0072] The method for designing a light source to be used under light-blocking control in this embodiment involves the following steps: obtaining the emission spectrum of a reference light source that provides the illuminance required for light-blocking control, using the absorption coefficient of the photosensitive substance to determine the absorbed energy in the photosensitive substance when irradiated with the emission spectrum of the reference light source obtained in the above step, using the absorption coefficient of the photosensitive substance, determining the absorbed energy in the photosensitive substance when irradiated with the emission spectrum of the light source to be evaluated, using the absorption coefficient of the photosensitive substance, and determining the ratio of the absorbed energy when irradiated with the reference light source to the absorbed energy when irradiated with the light source to be evaluated, and designing a light source such that this ratio is 1 or greater.

[0073] Each step will be described below using an example in which the photosensitizer is talaporfin sodium, the reference light source is assumed to be sunlight, and its illuminance is 500 lux. If the candidate light source that has the greatest effect on photosensitivity among all candidate light sources, including sunlight, is a light source other than sunlight, it will be replaced with the reference light source.

[0074] Specifically, the present embodiment differs in that the illuminance required for the photosensitivity test is used in step (a1) of embodiment 1, whereas the illuminance required for light shielding management is used in the corresponding step, but the other processing details are the same as those of embodiment 1. Therefore, the following description will be given by citing the description of embodiment 1.

[0075] The illuminance L required for shading control was set to 500 [lux], and the same processes as those in the first embodiment were carried out using the irradiation spectrum (FIG. 4) of, for example, a white LED (Nichia Chemical, NSDW570GS-K1 (b4p11)) as the light source to be evaluated. Since the light source for shading control of 500 lux is not specified, the light source is assumed to be sunlight, and the illuminance L required for the candidate light source that has the same absorbed energy as that of 500 lux is calculated. ＬＥＤ The result was as follows: L ＬＥＤ =2098[lux] (4)

[0076] In addition to LEDs for lighting that cannot change their spectral waveform, such as this white LED, there is also the RGB-LED (OptoSupply, OSTCXBEAC1S), which contains three LEDs of red, green, and blue in one package and allows the brightness of each LED to be set individually. RGB-LED types are often used for indoor lighting because the color temperature can be changed.

[0077] For example, the emission spectrum measured when the color temperature is set to approximately 6000 K and white with a bluish tint is shown in Figure 10, and the emission spectrum measured when the color temperature is set to approximately 3500 K and white with a reddish tint is shown in Figure 11. As shown in both figures, the peak wavelengths of the spectrum of this RGB-LED are approximately 460 nm, 530 nm, and 630 nm, which overlap little with the peak wavelength of the molar absorption coefficient of talaporfin sodium (Figure 3). When the spectra shown in Figures 10 and 11 are used as emission spectra, the illuminance L of the light source at which the effect on photosensitivity reactions is the same as that of sunlight 500 lux is ＬＥＤ The results are as follows: ＬＥＤ (6000K)=2192[lux] (5) L ＬＥＤ(3500K) = 2390 [lux] (6) Similarly, using the emission spectrum of the sunlight LED (Fig. 5), the illuminance L at which the effect on photosensitivity reaction is the same as that of sunlight 500 lux was calculated. ＬＥＤ Furthermore, since fluorescent lamps are also sometimes used for indoor lighting, the emission spectra of a daylight fluorescent lamp (Panasonic, EFD15ED / 11EF2) and an incandescent fluorescent lamp (Panasonic, EFD15EL / 11EF2) were determined as examples. These are shown in Figures 13 and 14, respectively. Similarly, the illuminance L at which the effect on photosensitivity reactions is the same as that of sunlight 500 lux was determined. ＬＥＤ The results are shown in Table 2.

[0078]

[0079] As shown in Table 2, when using talaporfin sodium, the illuminance at which the absorbed energy is equal to that of 500 lux sunlight is greater than 500 lux for all light sources, indicating that sunlight has the greatest effect on photosensitivity reactions. For this reason, when designing a light source to be used under light-blocking conditions, 500 lux sunlight is used as the standard, and a light source with an absorbed energy equal to or lower than this can be selected. If a different photosensitizer is used, the light source and illuminance used as the evaluation standard can be appropriately set, taking into account the absorption coefficient of the photosensitizer. If a light source is designed to have an absorbed energy equal to or lower than the absorbed energy of irradiation with the reference light source, the emission spectrum of the designed light source is obtained, and the above-mentioned absorbed energy ratio β is calculated, and the ratio is 1 or greater than 1.

[0080] Generally, the illuminance in areas along the path of patients after PDT, such as hospital wards and dining rooms, is approximately 1000 to 1500 lux even in brightly lit areas, excluding areas exposed to direct sunlight. Therefore, by selecting an appropriate light source, it is possible to reduce the risk of photosensitivity while maintaining the same illuminance, and patients who require light-blocking management can use regular hospital rooms without any particular restrictions.

[0081] In this embodiment, the light source is designed to reduce the absorption energy of the photosensitizer. Therefore, the light source design method of this embodiment can be suitably used not only for designing a light source for use in a light-shielded environment after administration of a photosensitizer to a patient, but also for designing a light source for use in an environment where the effect of light irradiation on the photosensitizer must be reduced, such as a light source for illuminating the environment when preparing a drug using a photosensitizer, a light source for illuminating a room where a photosensitizer is stored, or a light source for ensuring the field of view and visibility during surgery and treatment. Furthermore, by applying the light source design method of this embodiment, it is possible to design lighting devices such as shadowless lamps and microscope light sources used during surgery, and endoscope light sources used during treatment.

[0082] Fifth Embodiment In this embodiment, a light-blocking management lighting device using a light source determined using the light source design method in the fourth embodiment will be described with reference to FIG.

[0083] Fig. 12 is a diagram showing an example of the configuration of a light-blocking lighting device for management using RGB-LEDs. As shown in Fig. 12, the light-blocking lighting device for management 200 is composed of an RGB-LED 11 as an illumination light source, a constant current source 12 for controlling the current value so as to maintain a constant irradiation output independently for each of the three color LEDs included in the RGB-LED 11, a control unit 13 for specifying the current value command value, and a power supply 15.

[0084] With the light-blocking management lighting device 200, the color temperature of the RGB-LEDs can be increased by increasing the current setting value of the blue (B) LED and decreasing the current setting value of the red (R) LED relative to the green (G) LED (FIG. 10). Conversely, the color temperature of the RGB-LEDs can be decreased by decreasing the current setting value of the blue (B) LED and increasing the current setting value of the red (R) LED (FIG. 11). Therefore, with the light-blocking management lighting device 200, it is possible to configure (white) lighting under light-blocking management while allowing flexibility in color temperature.

[0085] [Embodiment 6] This embodiment describes a verification test for the applicability of the light source designed in the above-described embodiment for photosensitivity testing and light-shielding management. Specifically, after administering a photosensitizer to animals, irradiation tests using various light sources were conducted after a predetermined time period to confirm whether different skin toxicities were manifested depending on the light source. The test animals were 10-week-old Crl:CD (SD) male rats (five rats per group for Test Examples 1-3, and three rats per group for Reference Examples 1 and 2). The photosensitizer was administered via the tail vein at a dose of 10 mg / kg using a talaporfin sodium solution adjusted to 10 mg / mL in physiological saline. After administration, the test animals were maintained at an illumination intensity of 10 lux or less. The irradiation test method was as follows: (1) Prior to irradiation, the animal's back hair was removed to prepare the irradiation site. (2) Irradiation with the light source was performed immediately after administration, 8 hours, 24 hours, and 7 days after administration. The irradiation site (1.5 cm x 1.5 cm) is changed for each irradiation point. (3) During irradiation, the animals are anesthetized with isoflurane using an inhalation anesthesia machine for laboratory animals and are held in a prone position. (4) A light-shielding sheet is placed on the animal to prevent light from reaching areas other than the irradiation site. (5) The tip of the light source's light outlet (the tube covering the light source) is brought into contact with the irradiation site, and irradiation is carried out for 5 minutes. (6) After 5 minutes of irradiation, the condition of the skin at the irradiation site is evaluated according to the Draize evaluation criteria shown in Table 3. Specifically, evaluation is carried out for "1) erythema and crust formation" and "2) edema formation" on the Draize evaluation criteria, and the average value for each group is the sum of the maximum scores for each score.

[0086]

[0087] The actual evaluation results are shown in Table 4. Reference Example 1 is a test example in which an irradiation test was carried out without administering a photosensitizer to animals, and Reference Example 2 is a test example in which a photosensitizer was administered to animals and the skin condition was observed without irradiating with a light source.

[0088] As shown in Test Examples 1 and 2 in Table 4, equivalent results were obtained with Light Source A and Light Source B, which have different illuminances. This confirms that by designing a light source according to the above-described embodiment, even a red LED light source with a lower illuminance than a sunlight LED can be used as a light source for photosensitivity tests.

[0089] Furthermore, the results of Test Example 3 in Table 4 suggest that caution should be exercised when controlling shading when it comes to strong light such as direct sunlight, and that a white LED light source designed according to the above-described embodiment can be used as a light source for shading control even if it is a light source with an illuminance of 2000 lux.

[0090] The present invention is not limited to the above-described embodiments and may be modified in various ways within the scope of the claims. For example, the above-described embodiments have been described using talaporfin sodium as an example of a photosensitizer, but the present invention is also applicable to the design of light sources for photosensitivity testing or light-blocking management when other photosensitizers, such as sarcolemmal sodium, aminolevulinic acid hydrochloride, verteporfin, or porfimer sodium, are used in PDT. Therefore, embodiments obtained by combining technical means modified as appropriate within the scope of the claims are also included within the technical scope of the present invention.

[0091] (Summary) As can be understood from the above description, the present invention includes the following aspects. Aspect 1: A method for designing a light source for a light irradiation device used during use or storage of a photosensitizer or during management of a patient administered a photosensitizer, comprising the steps of: (a1) obtaining a reference light source spectrum that is the emission spectrum of a reference light source; (a2) obtaining an evaluation light source spectrum that is the emission spectrum of a light source under evaluation; (a3) ​​obtaining an absorption coefficient of the photosensitizer; and (a4) using the absorption coefficient, the reference light source spectrum, and the evaluation light source spectrum to determine a ratio of the reference light source absorption energy that is the energy absorbed in the photosensitizer under irradiation with the reference light source to the evaluation light source absorption energy that is the energy absorbed in the photosensitizer under irradiation with the reference light source, and designing a light source using the ratio. Aspect 2: The method for designing a light source according to Aspect 1, comprising determining the evaluation light source absorption energy using the absorption coefficient and the evaluation light source spectrum, and determining the reference light source absorption energy using the absorption coefficient and the evaluation light source spectrum. Aspect 3: The method for designing a light source according to Aspect 1 or 2, comprising determining a required current value, which is a value obtained by multiplying the current value when the spectrum of the light source to be evaluated was obtained by the ratio. Aspect 4: The method for designing a light source according to any one of Aspects 1 to 3, wherein a light source to be evaluated having a smaller required current value is selected as a more suitable light source. Aspect 5: The method for designing a light source according to any one of Aspects 1 to 4, wherein the light irradiation device is a light irradiation device used in photosensitivity testing of photosensitizers, and the light source is designed so that the ratio is 1 or less than 1. Aspect 6: The method for designing a light source according to any one of Aspects 1 to 4, wherein the light irradiation device is a light irradiation device used for managing the photosensitizer or for light-shielding management of a patient administered the photosensitizer, and the light source is designed so that the ratio is 1 or greater than 1. Aspect 7: The method for designing a light source according to any one of Aspects 1 to 5, wherein the light irradiation device is a light irradiation device used in a photosensitivity test of a photosensitive substance, and the light source is designed so that the value obtained by multiplying the irradiation time when using the light source to be evaluated by the absorbed energy of the light source to be evaluated is greater than the value obtained by multiplying the irradiation time when using a reference light source by the absorbed energy of the reference light source.Aspect 8: The method for designing a light source according to Aspect 7, wherein the reference light source is sunlight of 20,000 lux, and the irradiation time when using the reference light source is 5 minutes. Aspect 9: The method for designing a light source according to any one of Aspects 1 to 8, wherein the photosensitizer is talaporfin sodium, saratalocan sodium, aminolevulinic acid hydrochloride, verteporfin, or porfimer sodium. Aspect 10: The method for designing a light source according to Aspect 5, further comprising: using the spectrum of the light source to be evaluated and the ratio, determining the illuminance of the light source to be evaluated at which the ratio is 1 or less than 1. Aspect 11: The method for designing a light source according to Aspect 5 or 10, wherein the light source to be evaluated is a white LED containing a component corresponding to a maximum wavelength in the visible light region of the absorption coefficient of the photosensitizer. Aspect 12: The method for designing a light source according to Aspect 5 or 10, wherein the light source to be evaluated is a monochromatic LED having a peak wavelength that is the same as one of the maximum wavelengths in the visible light region of the absorption coefficient of the photosensitizer. Aspect 13: The method for designing a light source according to Aspect 2, wherein the evaluation light source absorbed energy and the reference light source absorbed energy are calculated in a wavelength range of 350 nm to 700 nm. Aspect 14: The method for designing a light source according to any one of Aspects 5 and 10 to 12, wherein the photosensitizer is talaporfin sodium and the reference light source is sunlight of 20,000 lux. Aspect 15: The method for designing a light source according to Aspect 6, wherein the photosensitizer is talaporfin sodium and the reference light source is sunlight of 500 lux. Aspect 16: A light irradiation device used in a photosensitivity test, comprising a light source designed by the method for designing a light source according to any one of Aspects 5, 7, 8, 10, 11, 12, and 14, and a control unit that controls the magnitude and time of a current applied to the light source. Aspect 17: A light irradiation device used in the management of a photosensitizer or in the light-shielding management of a patient administered the photosensitizer, comprising a light source designed by the method for designing a light source according to Aspect 6, and a control unit that controls the magnitude of a current applied to the light source.

[0092] The present invention can be used in light shielding management accompanying photodynamic therapy and in the design of light sources used therefor.

[0093] 1 LED 2, 12 Constant current source 3, 13 Control unit 4 Indicator unit 5, 15 Power supply 11 RGB-LED 100 Light sensitivity testing device 200 Light-shielding management lighting device

Claims

1. A method for designing a light source for a light irradiation device used when using or storing a photosensitive substance or when managing a patient who has been administered a photosensitive substance, comprising: (a1) a step of obtaining a reference light source spectrum, which is the emission spectrum of a reference light source; (a2) a step of obtaining an evaluation light source spectrum, which is the emission spectrum of a light source to be evaluated; (a3) ​​a step of obtaining an absorption coefficient of the photosensitive substance; and (a4) a step of using the absorption coefficient, the reference light source spectrum, and the evaluation light source spectrum to determine a ratio of the evaluation light source absorption energy, which is the absorption energy in the photosensitive substance when irradiated with the reference light source, to the evaluation light source absorption energy, which is the absorption energy in the photosensitive substance when irradiated with the reference light source, and designing a light source using the ratio.

2. A method for designing a light source according to claim 1, comprising: determining the absorption energy of the light source to be evaluated using the absorption coefficient and the spectrum of the light source to be evaluated; and determining the absorption energy of the reference light source using the absorption coefficient and the spectrum of the reference light source.

3. A method for designing a light source according to claim 1, further comprising: determining a required current value, which is a value obtained by multiplying the current value when the spectrum of the light source to be evaluated was obtained by the ratio.

4. The method for designing a light source according to claim 3, wherein the light source to be evaluated that requires the smallest current value is selected as the more suitable light source.

5. The method for designing a light source according to claim 1, wherein the light irradiation device is a light irradiation device used in photosensitivity testing of photosensitive substances, and the light source is designed so that the ratio is 1 or less.

6. The method for designing a light source according to claim 1, wherein the light irradiation device is a light irradiation device used for managing the photosensitive substance or for managing the light shielding of a patient administered the photosensitive substance, and the light source is designed so that the ratio is 1 or greater than 1.

7. The method for designing a light source according to claim 1, wherein the light irradiation device is a light irradiation device used in photosensitivity testing of photosensitive substances, and the light source is designed so that the value obtained by multiplying the irradiation time when using the light source to be evaluated by the absorbed energy of the light source to be evaluated is greater than the value obtained by multiplying the irradiation time when using a reference light source by the absorbed energy of the reference light source.

8. The method for designing a light source according to claim 7, wherein the reference light source is sunlight of 20,000 lux, and the irradiation time when using the reference light source is 5 minutes.

9. The method for designing a light source according to claim 1, wherein the photosensitizer is talaporfin sodium, sarotalocan sodium, aminolevulinic acid hydrochloride, verteporfin, or porfimer sodium.

10. The method for designing a light source according to claim 5, further comprising: determining the illuminance of the light source under evaluation at which the ratio is 1 or less, using the spectrum of the light source under evaluation and the ratio.

11. A method for designing a light source according to claim 5, wherein a white LED containing a component corresponding to the maximum wavelength in the visible light region in the absorption coefficient of the photosensitive substance is used as the light source to be evaluated.

12. A method for designing a light source according to claim 5, wherein a monochromatic LED having a peak wavelength equal to one of the maximum wavelengths in the visible light region for the absorption coefficient of the photosensitive substance is used as the light source to be evaluated.

13. The method for designing a light source according to claim 2, wherein the absorbed energy of the light source to be evaluated and the absorbed energy of the reference light source are calculated in the wavelength range of 350 nm to 700 nm.

14. The method for designing a light source according to claim 5, wherein the photosensitizer is talaporfin sodium, and the reference light source is sunlight of 20,000 lux.

15. The method for designing a light source according to claim 6, wherein the photosensitizer is talaporfin sodium, and the reference light source is sunlight of 500 lux.

16. A light irradiation device used in photosensitivity tests, comprising a light source designed by the light source design method described in claim 5 or 7, and a control unit that controls the magnitude and duration of the current applied to the light source.

17. A light irradiation device used for managing photosensitive substances or for light shielding management of patients administered with said photosensitive substances, comprising a light source designed by the light source design method described in claim 6 and a control unit for controlling the magnitude of the current applied to said light source.

Images