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. 2012 Jul 3;21(2):129–136. doi: 10.5978/islsm.12-SG-04

Safety Guidelines for Diagnostic and Therapeutic Laser Applications in the Neurosurgical Field

Sadao Kaneko 1,✉
PMCID: PMC3944486  PMID: 24610991

1. Purpose

The purpose of these safety guidelines is to list the requirements that need to be strictly adhered to, in order to ensure the safety of the patient, doctor and medical personnel in the course of 1: Photodynamic diagnosis (PDD) of and photodynamic therapy (PDT) 1–3) for malignant brain tumors; and 2: Intra-operative cerebral-vascular angiography for cerebral vascular diseases using indocyanine green as the contrast medium.

2. Requirements of the medical facility for performing laser treatment

In order for the facility to perform PDD and PDT for malignant brain tumors and perform intra-operative angiography for cerebral vascular disorders, the medical facility must possess adequate hardware and machinery including laser or light devices delivering light energy at an appropriate wavelength together with medical personnel who are well trained and capable of operating the hardware and devices and who have a thorough knowledge of the photosensitizer being used for the PDT procedure. Such a facility would be one accredited by the Japan Society for Laser Surgery and Medicine either as an instructional or certified facility and where a neurosurgery specialist certified by the Japan Neurosurgical Society is in full time attendance.

3. Adherence to the user's manuals and appendices

Doctors and medical personnel performing PDD of and PDT for malignant brain tumors or intra-operative angiography for cerebral vascular disorders, must have thoroughly read and comprehended the documents and instructions for use which accompany the photosensitizers. These include Photofrin® Injection 75 mg (Photofrin), Laserfrin® Injection 100 mg (Laserfrin), 5-aminolevulinic acid ( ALA ) and Diagnogreen® Injection 25 mg (ICG). All staff must also be familiar with the user's manuals for the laser devices and light-emitting devices specific for each photosensitizer.

The head of the medical facility is required to ensure that the facility's Laser Safety Officer (LSO) adheres to the content of the instructions regarding the specific device and its environment while the LSO is required to ensure that the users of the laser or lightemitting device adhere to the content of the instructions for its safe and effective use.

If and when a complication due to medication or malfunction of the laser device occurs, a report on the nature of the complication and or malfunction must immediately be sent to the pharmaceutical company, laser manufacturer and, if warranted, to the appropriate regulatory authorities.

4. Concerning PDD 4–6)

1). Brain tumors indicated for PDD

Brain tumors indicated for PDD are resectable tumors whose grade of malignancy is expected to be worse than grade III according to the WHO staging of neuroepithelial tumors, through various clinical findings and imagery. However the efficacy of PDD for malignant meningiomas, benign gliomas and metastatic brain tumors has also been reported.

The patient must be informed that PDD is not covered by the Japanese National Health Insurance system, that PDD in itself has no therapeutic effect on the brain tumor, and that its sole purpose is to distinguish normal brain tissue from the brain tumor. Patients who have submitted written informed consent to undergo the procedure are eligible for PDD.

2). Contraindications for PDD in the field of neurosurgery

The followings are contraindications for PDD in the field of neurosurgery

  1. History of hyper photosensitivity or porphyria

  2. Hypersensitivity to ALA and/or Laserfrin

  3. Patients with severe cardio-vascular, hematologic, hepatic, gastrointestinal, renal, pulmonary, endocrine, neurological or psychiatric disorders.

  4. Patients in shock or suffering from severe hemorrhage.

  5. Patients with hemorrhagic tendencies

  6. Patients with severe infectious diseases

  7. Patients who are pregnant or breast feeding

  8. Others, and patients whose primary physician judges the patient as unsuitable.

3). For the safe performance of PDD, rules that should be observed are listed below in chronologic order of the course of the procedure

  1. Pre-PDD examination

    Clinical findings and imagery must confirm that the patient has a brain tumor and that the brain tumor is indicated for PDD, in addition to the patient's having an adequately good Laboratory finding should satisfy the following criteria:
    Leukocytes ≤ 3000/mm3 Hemoglobin ≤ 8.0 g/dl
    Platelets ≤ 100,000/mm3 AST ≤ 100 IU/l
    ALT ≤ 100 IU/l Creatinine ≤ 1.5 mg/dl
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  2. Examination of the PDD hardware

    The PDD hardware, such as lasers and light delivering devices, must be checked both visually and functionally proior to the administration of photsensitizers such as ALA and Laserfrin. ALA is used for the biosynthesis of protoporphyrin IX (PpIX) within the cells in the target tissue. When PpIX is irradiated withlight near the wavelength of 405 nm, excitation of the intercellular PpIX occurs and PpIX fluoresces, emitting light at a wavelength of 640 nm. The excitation light does not necessarily have to be a 405 nm laser light but could also be a narrow waveband of light including the wavelength of 405 nm. Presently available light emitting devices are as follows: 1: 300 W Xenon flashlamp attached to an optical fiber with a Nikon 405±10 nm filter attached to the tip. 2: A diode laser, such as the VLD-M1 (M&M corp). 3: Surgical microscopes with excitation light functions such as the OPMIPENTERO from Carl Zeiss and FL400 from Leica. Laserfrin bonds to albumin as soon as it is injected intravenously, and is preferentially taken up by the tumor cells where it accumulates. The intracellular Laserfrin is excited by 664 nm light and fluoresces at 672 nm light. The Panasonic diode laser PNL6405CNS is usually used as the excitation light source.

  3. Preparation and administration of photosensitizers.
    • a)
      Preparation and administration of ALA
      1000 mg of powdered ALA is dissolved in 50 ml of 20% glucose solution. The ALA solution is administered orally immediately after preparation (20 mg ALA/kg body weight). ALA should be administered 1 hour prior to the start of anesthesia.
    • b)
      Preparation and administration of Laserfrin One vial (100 mg) of Laserfrin is dissolved in 5 ml of normal saline under light shielded conditions. The solution is administered intravenously approximately 24 hours before the start of tumor resection, at an amount of 40 mg/ m2.

  4. Actual PDD

    After the dura is opened with a craniotomy, the area of the brain suspected of containing the tumor is irradiated with the excitation light. In the case where ALA is used as the photosensitizer, the incident power density should be greater than 5 mW/cm2, and in the case of Laserfrin, the power density should be set at 10 mW/cm2. Within the field of light irradiation, tissue seen to be fluorescing red is considered tumorous, and should be resected. While the brain tissue is being resected, language and motor functions should be monitored in order to keep the sequelae of the surgical procedure to a minimum. When ALA is used as the photosensitizer, the excitation light source does not necessarily have to be a laser, as long as the light is near the 405 nm absorption wavelength of PpIX. A low cut filter can be used to facilitate the observation of the red fluorescence. The Carl Zeiss surgical microscope PENTERO is equipped with both the excitation light source and the observation unit. Please note that diagnosing tumor tissue by means of red fluorescence is not a substitute for histopathologic diagnosis. The definitive diagnosis must await the final pathological assessment

  5. Post-PDD check list
    • a)
      Functional check of the light source Check the wavelength, power density and performance of the excitation light source.
    • b)
      Brain MRT
      Brain MRI must be performed within 24 hours of surgery in the case where ALA was the photosensitizer and within 72 hours if Laserfrin was used.
    • c)
      Systemic, vital signs
    • d)
      Laboratory data Peripheral blood count: erythrocytes, hemoglobin, leukocytes, differential leukocytes, platelets.
      Blood chemistry: total protein, albumin, total bilirubin, AST, ALT, γ-GTP, ALP, LDH, BUN, creatinine, Na, K, Cl, CRP Urinalysis: protein, sugars, urobilinogen
    • e)
      Electrocardiography
      An ECG examination should be administered the day after the procedure
    • f)
      Skin photosensitivity test
      When Laserfrin is used as the photosensitizer, hyperphotosensitivity is tested by exposing the dorsum of the hand to direct sunlight for 5 minutes. If hyperphotosensitivity is apparent, avoidance of direct sunlight and intense light is necessary. Periodic sunlight challenge tests are to be performed until no hyperphotosensitivity is evident. <Light shielding and management> When using Laserfrin as the photosensitizer, direct sunlight and intense light should be avoided as soon as Laserfrin is infused. Luminescence should be controlled to less than 500 lx. The patient's bed should be surrounded by light shielding curtains and the luminescence should be accurately measured with a luxmeter. Light shielding and management must continue until no hyperphotosensitivity becomes evident. During this period, continuous monitoring with a pulseoxymeter must not be performed, but should be measured periodically. Light shielding and management can be lifted once hyperphotosensitivity is gone, but from the point of retinal protection, the patient should wear protective glasses for at least one week after the operation.

  6. Informed consent

    The patient must be fully informed regarding all aspects of PDD including therapeutic effects, side effects, complications and also the fact that it is not covered by the Japanese National Health Insurance system. Following a full explanation of the above factors, the patient and a family member are required to submit written consent before the patient can undergo the procedure.

5. Concerning PDT 7–11)

1). Brain tumors indicated for PDT

Brain tumors indicated for PDT are resectable tumors whose grade of malignancy is expected to be worse than grade III according to the WHO staging of neuroepithelial tumors, through various clinical findings and imagery and metastatic brain tumors.

2). Contraindications for PDT in the field of neurosurgery

The following are contraindications for PDT in the field of neurosurgery

  1. History of hyperphotosensitivity or porphyria

  2. Hypersensitivity to ALA, Laserfrin

  3. Patients with severe cardio-vascular, hematologic, hepatic, gastro-intestinal, renal, pulmonary, endocrine, neurological or psychiatric disorders.

  4. Patients in shock or state of severe hemorrhage.

  5. Patients with hemorrhage tendencies

  6. Patients with severe infectious diseases.

  7. Patients in pregnancy or breast feeding

  8. Others, patients whose primary physician judges the patient as unsuitable

3). For the safe performance of PDT, rules that should be observed are listed below in chronologic order of the course of the procedure

  1. Pre-PDT examination

    Clinical findings and imagery must confirm that the patient has a brain tumor and that the brain tumor is indicated for PDD, in addition to the patient's having an adequately good physical status. Laboratory findings should satisfy the following criteria:
    Leukocytes ≤ 3000/mm3 Hemoglobin ≥ 8.0 g/dl
    Platelet ≥ 100,000/mm3 AST ≤ 100 IU/l
    ALT ≤ 100 IU/l Creatinine ≤ 1.5 mg/dl
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  2. Examination of the PDT hardware

    PDT hardware such as lasers and light delivering devices, must be checked both visually and functionally prior to the administration of the photosensitizers such as ALA, Photofrin and Laserfrin. Light delivering devices presently used are the M&M corp. diode laser DLD-R2 (wavelength 635 nm) for Photofrin and the Panasonic diode laser PNL6405CNS (wavelength 664 nm) for Laserfrin.

  3. Preparation and administration of photosensitizers
    • a)
      Preparation and administration of Photofrin 2 mg/ kg of Photofrin is slowly intravenously administered to the patient 48 hours prior to the operation. The patient is moved to a light shielded and protected environment. The luminescence of the environment should be such that it will not affect the patient's normal daily activities.
    • b)
      Preparation and administration of Laserfrin One vial (100 mg) of Laserfrin is dissolved in 5 ml of normal saline under light shielded conditions. The solution is administered intravenously approximately 24 hours before the start of tumor irradiation at an amount of 40 mg/m2. The patient should be moved to a light shielded environment.
      <Light shielding and management> When using Laserfrin as the photosensitizer, direct sunlight and intense light should be avoided as soon as Laserfrin is infused. Luminescence should be controlled to less than 500 lx. The patient's bed should be surrounded by light shielding curtains and the luminescence should be accurately measured with a luxmeter.

  4. Actual PDT procedure

    When the PDT procedure is about to start, doctors and medical personnel are required to wear protective goggles and irradiation with the light source must be performed according to the instructions and appendices appertaining to the specific device. Irradiation of normal brain tissue by the light source, aside from that of the periphery of the tumor, must be avoided. This is especially the case when Laserfrin is used, in which case the main trunk cerebral arteries must never be irradiated.

    If and when a malfunction of the irradiating device or a change in the patient's condition occurs, the procedure must be aborted at once. Caution is advised on continuous pulse oximeter monitoring of the photosensitized patient since skin damage due to these devices has been reported, depending on the type of device (periodic monitoring is preferred over continuous monitoring).

    The procedure for light irradiation differs in the following cases: a) Irradiation of the tumor under direct visualization through a normal craniotomy; and b) Interstitial irradiation where a probe is inserted into the tumor with a stereotaxic technique.
    • a)
      Laser irradiation through a craniotomy approach
      Following gross resection of the brain tumor, the remnant tumor tissue is irradiated with the light source. Laser energy is introduced through an optical fiber, and directed at the surface of the tumor. In the case of Photofrin, the excitation wavelength is 635 nm. The power density at the fiber tip is set at 200 mW/cm2 and the target tissue is irradiated for 15 minutes (180 J/cm2). The laser spot size should be adjusted so that the diameter of the spot is 1 cm. In the case of Laserfrin, the excitation wavelength is 664 nm. The irradiance at the fiber tip is set to 150 mW/cm2 and the target tissue is irradiated for 3 minutes (27 J/cm2). The spot size is adjusted to give an area of 1 cm2 (1 × 1 cm). The tumor is repeatedly irradiated with the laser following the procedure mentioned above, until the tumor has been irradiated in its entirety. In the case of PDT using Laserfrin, coverage and protection of the main trunks of the cerebral arteries with sterile aluminum foil is advocated.
    • b)
      Interstitial laser irradiation through approach by the stereotaxic technique.
      Photofrin is used as the photosensitizer in such cases. The excitation wavelength is 635nm and the fiber tip output is set to 200 mW/ cm2 and laser is irradiated for 15 minutes (180 Joule/cm2) per spot. The fiber tip should be moved at 1 cm intervals and the irradiation is repeated until the tumor has been irradiated in its entirety. Care must be taken if the output is set greater than 200 mW/ cm2 since carbonization of the fiber tip is known to occur.
  5. Post-PDT check list
    • a)
      Functional check of the light source Check the wavelength, power density and performance of the excitation light source.
    • b)
      Brain MRI
      Brain MRI must be performed within 24 hours of surgery in the case ALA was the photosensitizer and within 72 hours if Laserfrin was used.
    • c)
      Systemic, vital signs
    • d)
      Laboratory data
      Peripheral blood count: erythrocytes, hemoglobin, leukocyte, differential leukocyte, platelet.
      Blood chemistry: total protein, albumin, total bilirubin, AST, ALT, g-GTP, ALP, LDH, BUN, creatinine, Na, K, Cl, CRP Urinalysis: protein, sugars, urobilinogen
    • e)
      Electrocardiography
      An ECG examination should be performed the day after the procedure
    • f)
      Skin photosensitivity test
      When Laserfrin is used as the photosensitizer, hyperphotosensitivity is tested by exposing the dorsum of the hand to direct sunlight for 5 minutes. If hyperphotosensitivity is apparent, avoidance of direct sunlight and intense light is necessary. Periodic sunlight challenge tests are to be performed until no hyperphotosensitivity is evident.

  6. Light shielding and management for Photofrin

    A hyperphotosensitivity test is performed 1 month following the administration of the drug, as instructed in the appendices accompanying the drug. If the test shows negative for hyperphotosensitivity, the patient may return to normal daily living, however the patient should be advised to avoid direct sunlight for a more prolonged period of time.

    If the test shows positive for hyperphotosensitivity, light shielding and management is continued until the test shows negative. If the patient is capable of light shielding and management by him/herself, early release from the hospital is possible. However, the patient is required to comply with instructions given, and have the necessary knowledge and understanding of hyperphotosensitivity so that necessary precautionary measures will be taken.

  7. Light shielding and management for Laserfrin The patient must be shielded from light following the operation until no hyperphotosensitivity is seen (luminescence less than 500 lx, light shielding curtains). During this period, continuous monitoring with a pulse oximeter should not be performed, and only periodical monitoring is advocated. Light shielding and management may be lifted once hyperphotosensitivity is gone, but from the point of retinal protection, the patient should wear protective glasses for at least one week after the procedure. If the patient is capable of light shielding and management by him/herself, early release from the hospital is possible. However, the patient is required to comply with instructions given, and have the necessary knowledge and understanding of hyperphotosensitivity so that necessary precautionary measures will be taken.

  8. Informed consent

    The patient must be fully informed of all aspects of PDT including therapeutic effects, side effects, complications and also the fact that it is not covered by the Japanese National Health Insurance system. Following a full explanation of the above factors, the patient and a family member are required to submit written consent before the patient can undergo the procedure.

6. Intraoperative cerebral angiography with ICG

ICG (indocyanine green) is officially listed as a medical product used for testing hepatic function and evaluation of cardiovascular function. ICG has an absorption spectrum from wavelengths between 700 nm and 850 nm (max. at 850 nm). ICG is excited at these wavelengths and fluoresces at wavelengths between 780 nm and 835 nm (max. 835 nm). This reaction is used for cerebral angiography, in order to assess the patency and/or area of blood perfusion, and to confirm preservation of normal blood vessels. Since both the excitation light and resulting fluorescence are infrared and invisible, an infrared camera is required for visualization. This method of angiography is not covered by the Japanese National Health Insurance system, and only patients who have been notified of this fact and are still willing to receive this method of angiography are to be included as candidates.

1). Disorders indicated for intra-operative ICG cerebral angiography

Almost all cerebral vascular disorders such as aneurysms, bypass operations, and arterio-venous malformation are indicated for this procedure.

2). Contraindications of intra-operative ICG cerebral angiography

Patients with a history of iodine hypersensitivity are contraindicated. Caution must be exercised in the case of patients with allergic diseases.

3). The following is a list of rules for the safe performance of intra-operative ICG cerebral angiography

  1. Pre-angiography check of the hardware

    Both visual and functional checks of the light delivery system and fluorescence observation systems are required prior to the administration of the photosensitizer.

  2. Preparation and administration of ICG

    Once the target blood vessel is within the visual field of the microscope, 1 vial of ICG is dissolved in 5 ml of distilled water, and is rapidly intravenously infused at the amount of 0.2–0.5 mg/kg. In general, 1 ml (5 mg) suffices for most observations. If necessary, the procedure can be repeated.

  3. Angiographic observation

    The target tissue is irradiated with the excitation light with between 700–850 nm, resulting in fluorescence at wavelengths between 780–835 nm. Since the range of both the excitation light and fluorescence is in the infra-red, the light energy is invisible to the naked eyes hence use of an infrared camera becomes necessary for observation. Surgical microscopes equipped with both an excitation light source and observation systems can be found on the market. Caution is advised for prolonged observation, since prolonged observation means prolonged irradiation of the target tissue with the infrared excitation energy, and may cause thermal damage to the brain surface.

  4. After the ICG angiography

    Observe for any allergic reactions to the ICG

  5. Informed Consent

    The patient must be fully informed of all aspects of intra-operative ICG angiography including therapeutic effects, side effects, complications and also the fact that it is not covered by the Japanese National Health Insurance system. Following a full explanation of the above factors, the patient and a family member are required to submit written consent before the patient can undergo the procedure.

7. Rules and stipulations for the manufacturers and their distributors of PDT related drugs and laser hardware

1). Obligation of the manufacturers and distributors to offer complete information on the products through user's manuals and appendices

All manufacturers and distributors of drugs and laser hardware associated with PDT must provide ample and sufficient information to institutions, medical and paramedical personnel through the user's manual and appendices to ensure the proper and safe usage of the drugs and laser devices. This may be done through technical seminars showing actual video footage of PDT procedures, either independently or at meetings and congresses of relevant medical societies with the cooperation of those societies. The manufacturers/distributors are required to disseminate information for the safe and effective treatment with PDT.

The content and information that are required in the user's manual are dictated in the “Instructions for the use of laser devices”, release no. 524 Notice from the Division Head of the Evaluation and Licensing Division, Pharmaceutical Affairs Bureau of the Japanese Ministry of Health, Labour and Welfare, dated April 22nd, 1980. The content concerning checking and maintenance of laser devices must include: (a) daily preoperative checks involving both visual and operational checks; (b) intraprocedural checking (checking while the device is actually being used); and (c) postoperative checks to be performed at the end of the day, including checks to be performed on the day after the procedure, and cleaning up.

2). Written confirmation of delivery of the laser devices

3). Items requiring written confirmation upon the delivery of the laser device

Upon the delivery of the laser device, the distributor and the medical facility must sign and seal a written confirmation concerning the items listed below, abiding by Appendix 2 of “Rules and Regulations of the Manufacturer and Distributor” from the business communications of the Division of Medical Device Development, Pharmaceutical Affairs Bureau of the Japanese Ministry of Health, Labour and Welfare, dated August 6th, 1991. Two copies of this written confirmation must be made, each party keeping a single copy.

Subjects requiring confirmation upon delivery of the laser device

  1. That laser safety officers (LSOs, chief and deputy, at least 2 people) are assignedand present.

  2. That a registered users’ list has been made

  3. That the planned users of the device are surgeons who are board certified by the Japan Neurosurgical Association and the Japan Society for Laser Surgery and Medicine, and that the LSO has the right to appoint the user of the device.

  4. That the user is technically qualified and has attended courses for handling the drug and laser device, laser safety management, risk assessment and hazard prevention.

  5. That the laser device is key controlled, and that the safe keeping of the key has been determined by the LSO.

  6. That appropriate protective goggles appropriate for the wavelength of the laser device are supplied.

  7. That a dedicated earth terminal is made available.

8. Disclaimer

1). Discretionary power of the medical doctor and medical malpractice law suits and these guidelines

These clinical guidelines are designed to be used with flexibility, according to the individual circumstances of each procedure. It is not the purpose of these guidelines to limit or restrict the discretionary powers of medical doctors, nor is it the purpose of these guidelines to be used as material for legal issues concerning medical malpractice, and so on. These guidelines list the present day medical standard gained from objective bodies of evidence viewed from the clinical standpoint of a medical doctor.

2). Concerning the use of unapproved drugs and treatment methods in these guidelines

These guidelines are based on purely scientific facts and evidence gathered from domestic sources or from abroad. Whether or not a drug or a procedure is approved by the Japan National Health Insurance is completely irrelevant. These guidelines have been put together for scientific purposes only, and do not purport to be a guide for Japanese National Health Insurance system-covered medicine. It would be incorrect for anyone to assume that these drugs can be freely used or the procedures freely performed because they happen to be mentioned in these guidelines. For the use of unapproved drugs, each facility should have their own system of application and approval. When unapproved drugs are to be used, informed consent is necessary as is the case for all drugs.

9. Changes to the Guidelines

These guidelines will be changed and amended as necessary based on new medical evidence, in order to pursue the safe and effective application of PDD and PDT. It should be noted that all facilities should make their own instructional, informational material including the clinical protocols that are individually appropriate for each facility.

These guidelines were translated from Safety Guidelines for Laser Surgery and Medicine — 2011 version, supplement of The Journal of Japan Society for Laser Surgery and Medicine, Vol. 32, with the permission of the Safety Committee of the Japan Society for Laser Surgery and Medicine

Acknowledgments

I thank Professor Akimoto heartily. The content about Laserfrin was written by Professor Akimoto.

Professor Jiro Akimoto is associate professor, Dept. Neurosurgery, Tokyo Medical University.

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