CA1192416A - Metabolism monitoring apparatus - Google Patents

Abstract

Abstract Metabolism Monitoring Apparatus A mounting structure secures to a selected portion of the human body, e.g., the head, and incorporates light source and light detecting means adapted for association with spectrophotometric circuitry for in situ, in vivo monitoring of local metabolism or another selected body activity in the area of the body where the structure is secured.

Description

Description METABOLISM MOMITORI~G ~'PAR~TUS

Technical Field The invention relates to spec-trophotoinetric apparatus for monitoring seleeted characteristics of the human body in vivo and more speci-fically to apparatus associated with the monitoring apparatus for mountin~ and providiny light shielding for light source an-l light ~letector means on ~le body, par-ticularly on the head of a living hurnan patient.

Back~round Art In prior United States Patents 4,223,680, 4~281,~4~ and 4,321,930, there has he~n describe~ a spectrophotometric method and apparatus directed to noninvasive, continuous, atraumatic, in vivo, in situ monitoring oE metabolism in a body organ. In the describad applic~tions set forth in these patents, measuring and reference wavelengths within the near-infrared region, i.e., 700-1300 nm, are utilized Eor non-invasive, continuous, atraumatic, in -~ivo, in situ moni-toring of oxidative rnetaholism by monitorin~J oxy~en su-~iciency in an in-ternal organ, e.g., the brain, o~ a huMan or animal body. Advantage is taken of the critical c~arac-teristic of cellular enzyme cytochrome a, a3 (also known as eytochrome c oxidase and identified by EC 1.9.3.1) within the optical path and within the radiated portion o the selectetl organ for absorbiny the selecte~ Ineasuring wavelen~th and for light of t~is measuring wavelength, as well as at least;one :,........................................................ ~,, reference wavelength witllin the sa~ne deined infrared re-~ion and at a low, non-hazardous level o~ in~ensity to ~e detectable at t~le end of a relatively loncJ transillu~inatior or r~lectance path, e.~., oE several celltimeters lencJth, which may include substantial content oE bone as w~ll as soEt tissue and skin. Variations in metabolic and circulatory paralneters during mea6uring are recocJnized and the selection o' wavelengths, circui-try and m~thod also provide techniques for colnpensating or changes in blood volume in the organ being monitored, for continuous Inonitoring of helnoglobin oxygenation and blood volume, for intermittent monitoring of blood flow rate, ~or skin blood flow effects and variations in the light source, i.e., laser dio~e, output.
The prior art is discussed extensively in -the mentioned prior patents and in the context of -the prior patents and other prior art cited in the those paten-ts, the present invention is primarily concerned with -the lig~t sour~e an~
light detecting structure at t'ne place oE attachment -to t~e body and with the means for mounting the light source~ ht detecting structure on the body. Thus, t~e present invention i5 primarily intended to provide an improvement over the light source-light detecting structure shown in the prior patents as well as over all known prior art deemed relevant to the invention. Other uséful background may be had by making reference to the light source and light detecting structures described in United States Patents Nos. 3,527,932; 3,674,008;
3,63B,640; 3,704,703; and 4,077,399.
Taking all of the foregoing into account, further levelopment and experimentation with the spectrophotometric apparatus and method for measuring local metabolism described in the mentioned patents has revealed the need for an improved means for securing and shielding the light sources as ~ell as the light detectors when a'tached to the body and particularly in reference to improving the light source-detector mounting 35 arrangement described in United States Patent 4,321,930. Also, a need has arisen for further simplification of the light source-light detecting structure which is attaehecl to the body and to the associated ~ounting structure such that it can be , r . , : ~ l made economic~lly in a disposable form ancl wh~re necessary Eor a singLe end use application such as in a sLlrgical operation, emergency acciaent situations, and the like.
A need has also arisen for an improved Eorm of mounting in those medical and surgical procedures in which tl~e patient is prone and the head of the patient is required to be tilted back, either for examininy or introduciny substances or instruments into the throat o the patient.
The achievement o these various needed improvements tllus becomes the general object of the invention and other ob]ects will be revealed as the description p~oceeds.

Disclosure of Invention The invention is directed to improvements in means ~or orienting in reference to the body, supportin~ on and attaching to the body5 and shielding from ambient light at the point of attachment the liyht sources and the light detectors associated with remotely located spectro~hotometric apparatus ~utilized for measuring local metabolism in vivo, non-invasively and atraumatically according to the teachings o~ the rela-ted and previously mentioned prior patentsD
The invention apparatus is attached to the body, e.g., the head, a limb~ or to the torso, and operates with the apparatus and according to the tec~niques o~ t~e prior patents. Decisive infor~nation is provided on the parameter of oxygen sufficiency in the tissue or organ in question, in vivo. The invention apparatus, w~en operating in conjunction with the apparatus and techniques of the prior patents also providPs the capability of monitoring t~e oxygenation state of the blood being supplie~, blood volume and blood flow rate in the portion of the body beiny monitored and in a manner which is non-invasive and atraumatic.
As distinct from the means -Eor generating the near-infrared light sources, the timing, detecting and processing circuitry of the prior patents, the present invention is pri-marily concerned with improvements in the body-Mounted light emitting and light detecting components and with împroved means for detachably mounting, light shielding and orienting such ligh~ sourc~-detectin~ comp~nen~s on the body and in a manner desi~ne~ to avoid e~ces~ive l~calized pressure ancl erroneou~
signal cond.itions.
l'he bo~y-mourlted invention ap~aratus is u-tilized in S association with the near~infr~red sources, -timing, detecting and processin~ circuitry as well as the measuring techniques described in the prior paterl~s. Thus, by rna~.ing reEerence to the subject matter oE the prior patent~, it will be understood that the present inven~ion apparatus facilitates the carrying out of a continuous, non-invasive, in vivo, in 5i-t~ monitoring of the redox state of cytochrome a, a3 in the body por-tion o~
interest by using the deep, difuse, multiple-scattered light, reflectance or transillumination technique and near-in~rared radiation within the range of about 700-1300 nm as referre~ to and ully described in the prior patents. When the inventi.on apparatus is applied to the head, for example, the light source and light detector components are spaced apart on -the same side of the head and the light reflected and scattered - back to the light source location is detected and used in the associated processing c~rcuitry o~ the prior patents as a correction for skin blood volume changes. The present invention is particularly advantageous in minimizing light loss and also ~ini~izing the establishment of locali~ed pressure conditions and thus avoiding erroneous signal conditions. The present invention apparatus also further enhanc~s ~-e ability to discriminate between light sca-ttered by the gray matter and light reElected from the w~ite matter of the brain so as to provide a signal known to be indicative o-f the oxygen sufficiency in the gray matter of the brain.
With more specific reference to the actual structure employed in the improved light source light de~ector body mounted apparatus of the invention, two embodiments are provided. There is provided in a ~irst embodiment a strap designed to be wrapped around a sele~ted portion of the body, e.g., around the head, a limb, or the torso, with the strap ends detachably secured for the purpose of supporting and orienting the light source, .light detector, light shiel~ing ., , ~iber optic and cable componen-ts o~ the invention. The mentioned strap mount~ intermedi~te it5 len~th a block or section of resilient material ad~pted to conform to -the shape of the body at t~e place oE attachment. Such re~ilient 5 material also serves as a means for encasing a pair o~ optical modules, the terminal ends of which serve as the required li~ht source and light detector elements. These kerrninal ends are adapted to be detachably connected by quick disconnect couplings to a cable assembly usea to transfer light vr light related signals between t~e body-mounted apparatus oE the invention and external apparatus providing the light sources, the timing~ detecting and processing circuitry in which t~e deslred spectrophotometric measurements are actually made according to the techniques of -t~e prior patents.
As compared to the ]ight source-detector assembly of United States Patent 4,3~1,930, both embodiments of the presen-t invention provide an overall further sim~lified assembly. Addi-tionally, improvements are provided by ~orrning ~the light source and detector elements as uniquely constructed and se~arately mounted modules. The present invention also provides an improved means of light shielding obtained by using a double-sided, annular adhesive tape around the optical ~aces to improve both li~ht shielding and body securement.
- Further, the first embodiment oE ~he present invention provides the option of using a va~uum sealing arrangement in conjunction with a strap arrangement to further en~ance securement of t~e light source-detector elements to the body and whether of the fiber optic or electronic type.
In the second embodiment, a strap is not require~ an~ the light source and light detector modules are mountea, light shielded, and accurately spaced by means o an adhesive pad arran~ement. This is of particular significance in those medical and surgical procedures in which t~e patient is prone and t~e head of the patient is required to be tilted bac~;, either for examining or introducing substances or instruments into the throat of the patient.
Both ernbodiments of the body~mounted invention a~paratus provide means for detecting li~ht reflected and scattered back ., ~,.

from t~e location w~ere t~e li~h~ irst enters the ~ody as welL as separate means for de-tecting both scattered and reflec~ed light a-t a poin~ spaced Erom the light entry point.
The inventi~ apparatus a3so provi~es improved li~ht shieLding S to prevent entry o~ ambient light or other extraneous li~ht signals and also in a manner desi~ned to ~void the establishment o harrnful localized pressure ~t those poin-ts where the lig~t enters and is detec~ed. Thus, correc~ion for skin blood volume changes i5 provi~ed in all embodiments by means of monitoring the light reflected back at ~he point of light entry in conjunction with using the light reElected and ~cat-tered back to the second point for processincJ according to the techniques of the prior patents.
In both embodiments, the incoming li~ht i6 transferred to the body-mounted apparatus of t~e invention by means of an optical cable connected to the light source elenlent of t~e body-mounted apparatus. The corrective light reflected back fro.n the body at the point where light from the light source enters the body as well as t~e measuring light reflected and sca-ttered bacX to a point spaced from t~e light source are both detected and transmitted for processing by optical fiber means. The reflectance technique utilized by the present invention should be cons-trued as ~he deep reflectance technique fully described in prior United States Patent ~,321,930.

Description of the Drawings Figure 1 is a pictorial view of the body mountable light source-light detector apparatus according to a first embodiment of the invention.
Figure 2 is an enlarged partial section view taken substantially along line 2-2 of Figure 1.`
Figure 3 is a plan view of an optical module suited to the apparatus of Figure 1.
Figure 4 is an end view of the op-tical Inodule oE Figure 3 taken in the direction of line 4-4 of Figure 3.
Figure 5 is a section view taken substantially along l.ine 5-S of Figure 3.

Figure 6 is a section view ~aken substantially along line 6-6 o Figure 3.
Figure 7 is a pietorial view o -~he body mountable lig~t source-light detector appara-~u~ illustrating a modiEication o the first em~odiment of the invention ~stili~ing a vacuurn attachment to the body.
Figure 8 i5 an enlarged partial section view taken substantially along line 8-8 of Fiyure 7.
Figure 9 is a plan view oE a vacuum adapted optical module suited to the apparatus of Figure 7~
Figure 10 is an end view of the optical module of Figure 9 taken in the direction of line 10~10 of Figure 90 Figure 11 is ~ section view takén substantially along line 11-11 of Figure 9.
Figure 12 is a sec-tion view taken substantially along line 12-12 of Figure 9.
Figure 13 is a plan view of a modified vacuum adapted optical module suit~d to the apparatus of Figure 7.
~ Figure 14 is a plan view o one side of an annular-shaped, double-sided, pressure sensitive tape use~ul with any of the optieal modules of the invention.
Fi~ure 15 is a pictorial view of the body mountable light source-light detector apparatus o-~ the invention according to a second embodiment and illustrated as being mounted on ~he ~orehead of a patient for monitoring the brain.
Figure 16 is a top plan view of the li~ht detector optical module used in the second embodiment.
Figure 17 is a side view of the light detector optical Inodule shown in Figure 16 and showing an annular light shieldin~ pad used in conjunction with such ~odule.
Figure 18 is a bottom view of the light detector optical module shown in Figure 16.
Figure 19 is a top plan view o~ the light source optical module shown in Figure 16.
Figure 20 is a side view of the light source optical snodule shown in Figure 19 and showing an annular light shielding pad used in conjunction with such module.
Figure 21 is a bottom view oE the li~ht source module shown in Figure 19.
Figure 22 is a si.de view of a modu].e mountlng ~oc~.et of the type used in the second embodiment of -t~e invention ~or receivin~ either a light sourc~ or light detector module and releasably securing the same to the body in spaced relation.
Fi~ure 23 is a top view oE the moclule socket shown in Figure 22.
Figure 24 is a bottom view of ~e module socket shown in Figure 22.
Figure 25 is an exploded side view illustrating how the light detector module of Figure 17 is assembled in the module socket ~ Figure 22.
Fi~ure 26 is a side view of the light detector module of Figure 22 fully nested in the module socket.
Figure 27 is a plan Vi2W of a light shielding pad used in the ~econd embodiment of the invention and adapted to secure and shield both the light detector module and the light source module after being nested in their respective sockets with the socket tabs adhesively secured to the body in spaced relation.
Figure 28 is an elevation view of th~ pad shown in Figure 27.
.Figure 29 is a plan view in reduced size of the light detector and light source modules as shown in Figures 1~ and 19 assembled in their respective sockets and illustrating how the socke-t tabs may be used as a means for accurately spacing the optical modules apart.
Figure 30 is a plan view in reduced size of the light detector and light source mo~ules as shown in Figures 16 and 19 assembled in their respective sockets and illustrating how the optical module spacing may be determined by ~he pad construction of ~igure 27.

Best Mode f~r Carryin~ Ou~ the Invention With $he background description provided by the prior patents~ it becomes evident that when the deep reflectance technique is followed, as described in prior United States Patent 4,321,930, the means employed ~or introducing and implementing deep penetration oE the near-infrared measuring and re~erence wavelengths at the point of light entry on the body, the means ernployed for collecting the directly and deeply re1ected li.ght at the point of ligh-t entry and the means for collecting the deeply penetrating light after heing sca-t~ered anfl reflected from the organ, e.g~, the brain or other bod~ portion of interest, are of crucial and signiEicant importance to obtaining meaningful measurements oE the parameters desired. It is desirable, for example, that the light source-li.ght detector assembly which i.s at-tached to the body be in a orm adaptable to various body shapes such as associated with the head, a limb, or torso of a human or animal subject under observation. It has also been found ~ritically important tllat light shiel~in~ associated with the body-mounted light source-detector assembly be effective both as to extraneous near-infrared as well as extraneous ambient light such that the light entering the body as well as ~he light detected will be only those wavelengths and only ~rom those light sources intended to be associated with the measurements. Extraneous photon energy at the measuring location which might otherwise enter the body and affect -the measurelnents is therefore desirably absorbed by means associated with the light source-detector assemhly of the -invention.
It has also become increasingly evident that '-the li~ht source-detector which attaches to the body must be in a form which avoids restricting local bloodflow or.any other tissue function in the area of observation so as to avoid erroneous signals'. Additionally, it has been found desirable that the light source-detector elements have an improved body mounting arrangememt that not only lends itsel~ to shielding of extraneous light but also protects the elements as the mounting assembly changes to con~orm to the body shape at -the area of observation. Another c~itical ~eature in the light source-detector element moun-ting structure is that the relative space between the light souree and detector elements remain ~ixed during the measuring period and not be subject to alterations by physical changes in body geometry brought about by breathing, flexing of the body, tr~uma, and the like.

~nother major consideration is t11at -the li~h-t source-de-tec~or assembly ~hich is mounted on the body be in a form a~apted to be quickly coupled and uncoupled -to the -timing, light source 3 detectin~ and processing circuitry typically located at least sever~l feet away from the patient~
As another important consideration, it has been found highly desirable that the light source-detector assembly which attaches to the body be in a form lendin3 itself to economical manufacture so as to be adapted to a single en~ use and useful as a disposable componentc Considering the difficulty and cost of washing and sterili~ation, the possibility of transmitting diseases and the likelihood of contamination in surgical and accident cases in particular, the advantage oE
having a prepacked, sterilized, single end use, disposable light source-detector assembly will be readily appreciated.
With the foregoing background information and desired ~haracteristics and objectives in mind, the description next ~akes reference to the drawings to illustrate how the same are achieved in the improved, body-mounted light source-light detector assembly of the invention according to a first embodiment utilizing a strap arrangement. After completing the description of two forms of the first embodimen-t, the description will then proceed to a description o~ the second embodiment which utilizes light source and light detector modules generally of the same type as described in reference to the first embodiment but with a different securing means.
After completing the description of two forms of the first embodiment, both of which use a strap-like arrangement but one of which uses a vacuum arrangement, the description will then proceed to describing the second embodiment basecl on using similar li~ht source-light detector nlodules with an adhesive pad arrangement for mounting rather than a strap arran~ement ~s in the first embodiment.
Referring initially ana principally to Figures 1-6, the improved light source-detector assembly 20 of the invention in a first embodiment basically comprises a base support strap 30, a module support 35 and embedded in support 35 a light source-detector module 50 and a light detector module 60.

4 ~

Base support strap 30 i5 preferably forrned of a tightly woven, elastic -Eabric such as found, Eor example, in elastic straps, stretchable belts, elastic fabric, and the like.
Strap 30 should preferably have an ability to stre-tch while providing su~ficient 1exibili-ty to conform to the sha~e of the head, limb or -~orso of a human or anirnal subjec-t under investigation. All surfaces of strap 30 are preferably black in color to assist in absorbing ex-traneous photon energy proximate to the observation area. T~e hody strapping ~nd unstrapping operation utili~ing strap 30 is facilitated by employment of mating "Velcro" type strips 40-~3 on the corresponding mating surfaces of strap 30 such that strap 30 can easily conform to the size and shape of body contour whera the light source-detector assembly 20 is attached for monitoriny purposes as described in the prior patents.
Strap 30 includes an in-termedia-te portion 30' adhered to an out~r side surface o w~at will be referred to as the Inodule support 35. A double-sided pressure sensitive tape 36 -is used for this pur~ose and provides a means for both positive securement and ease of removal o~ the module support 3S when necessary for purposes of replacement or service.
Module support 35 is preferably formed of a material which is both resilient and deormable to a degree suited to the invention a5 described. Foam, e.g., silicone rubber, represents a material which can be obtained with varyin~
degrees of resiliency and is deemed suited for this purpose.
Module support 35 is molded preferably with pre~ormed cavities, not shown, suited to lightly gripping and encasing the pair of optical modules 50, 60 which are suppor-ted by -Jnodule support 35 on strap 30.
While serving different functions, optical Inodules 50 and 60 are basically of similar construction ana will be described in reference to ~igures 2-6. Module 50, by way of example, comprises a hollow, circular-shaped housing 70 having a bacX
cover plate 71 and a slightly tapered or slightly rounded front face 72 formed with a central aperture 73. ~ fiber bundle 75 couples throu~h a quick disconnect optical coupling 76 and terminates with an L-shaped terminal end 79 having a cle ~",k ~round optical Eace 80 loca-ted in -the aperture 73. The void within housing 70 surrounding ~he L-sh~pecl terminal end 7~ is filled with an epoxy or similar hard set~ing compoulld to facilitate securement of ~he terminal ena 79 with:in housing 70 and back cover plate 71 is suitably gl~led or otherwise secured in place after su~h assembly.
Terminal end 79 o~ fiber bundle 75 provide~ both a near-infrared light source terminal and a corrective detector terminal with selected fibers being employed for bringing light to the point of light entry and other randomly dispersed selected fibers being employed for collectin~ ht reflected bacX directly from or near (1-3 mms) the point o light entry.
The manner in which such corrective and measured light sources operate and are processed are fully explained in ~he previousl~ referred to prior patents.
Module 60, as previously stated, employs a similar construction to that o module 50 and mounts a fiber bundle 80 through a quick disconnect optical coupling 81 having an L-shaped terminal end R2, not shown, with a ground optical face 83. Bundle 80 is used as a m~ans for collecting the - measured reflected light for processing as explained in the prior patents. During the light measuring op~ration, modules 50 and 60 are mounted in module support 35 and the invention assembly ~0 operates so as to maintain uniform -the spacing "S"
within the limits discussed in the prior patents.
Shielding of ambient light is deemed important especially when metabolic trends are being monitored and discrete changes are significant though small in value. Such shielding is provided by employing a layer of light shielding material 90 adhered to module suppor~ 35 and formed with suitable holes 91, 92 as illustrated to avoid covering the respec-tive optical faces 80, 83.
As another aspect o~ the present invention, a pair of double-sided, annular-shaped, pressure-sensitive, adhesive tapes 100, 101 are employed on the respective modules 50, 60 and used to assist in providing the desired ambient light shielding. Tapes 100, 101 are preformed in the shape illustrated ln Figure 14 and typically have removable adhesive protective covering which, after removal, allows the r~spective tapes 100, 101 to be attached on one side to the respective modules 50, 60 while leavincl the opposite side of the respective tapes 100, 101 exposed for securing to the respective body surfaces opposite the respective optical ~aces ~0, ~3.
In using the invention assembly 20, an optical ~el is applied to each optical ace ~0, 83 and strap 30 is secured -to the selected portion o~ the body so as to slightly compress the material forming module support 35 and bringing the respective optical ~aces 80, 83 with ~he respective surrounding annular tapes 100, 101 into ~irm enga~ement with the body surfaces to maximize light contact and minimize leakage and loss o light at t~e points of light entry and exit. T~e slightly tapered or rounded surfaces on the respective front faces, e.g., face 72 of module 50, have been founa useul in some applications as a means for facili~ating ~uch contact in view o the substantial variations in contour and surfaces found on ~he human body. Once t~e strap assembly ~0 20 of the invention h~s been properly secured as explained in -the previously mentioned prior patents, appropriate optical and electric~l circuits are established according to the prior patents and the present invention apparatu~ is used in the manner previously explained in such prior patents.
One of the important advantages of the improved strap assembly 20 of the present invention according to -the first embodiment resides in the ability to ~reform the respective optical modules 50, 60 and assemble such optical moaules with the module support 35 as a subassembly which can be quiclcly attached to the support strap 30 a~ previously explained and quickly coupled and uncoupled by means of t~e previously mentioned qùick disconn~ct couplinys 76, 81. Modules 50, 60 may be made of a suitable metal or plastic and mol~ea or machined into the previously described form. Any suitable fabrication means may be employed to obtain the L-shaped configuration of the term;nal ends of the respective optical bundles 75, 80 and to secure such optical bundles with respect to the respective optical modules 50, 60 so as to maintain t~le . ", \

respec~ive optical f~ce~ ~0, 83 fixed relative to the respective modules S0, 60.
Referriny next ~o Figures 7-13, there is described another form o the firs-~ embodiment of generally the sa~ne construction as the form of the first embodiment previously described but with the addition of a vacuum arrangement -to enhance light shielding and securement of the respective optical modules. As wi-th the irst form of ~e first em~odiment, the assembly 140 of the second form of the first embodiment employs a base support strap 150 and a module support 15S secured to strap 150 and having a layer of light shielding material 156 with suitable openings Eor light passage as with the ~irst form of the first embodiment.
Within module support 155, ~here is embedded a pair of pre~ormed optical modules 170, 180 of ~enerally similar construction and also generally constructed similar to the previously described modules 50 and 60 but adapted for vacuuTn securement to the body.
Using module 170 by way o~ exampleO the hollow ~ousing 1~1 mounts a fiber bundle 185 having an L-shaped terminal end 186. Terminal end 186 iB optically coupled through a quick disconnect optical coupling 187 and terminates with a ground optical face 190 ground flush with a central aperture 191 forrned in the slightly rounded or tapered front face 192.
Housing 181 is formed with an internal air-tight cha~ber by means of back cover plate 1~3 which is secured in place to prevent air leakage and also by means of appropriate sealing against air leaks around fiber bundle 185 and optical face 190. The internal air-tight chamber within housing 181 is coupled to an air tube 194 connected through a quick discon-nect coupling 195 to a suitable vacuum source, not shown.
Front face 192 of housing 181 i5 formed with four elliptical depressions 200 which co~nunicate through corresponding holes 201 to the vacuum chamber within housing 181 to which t~e vacuum supply air tube 194 is connected. In a third ~orm o~
the first embodiment shown in Figure 13, the elliptical depressions 200 are interconnected by other depressions 202 to increase the total body surface exposed to the vacuum efEect.

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~,

2~ ~
-~5-Module 180, in a simil.ar manner and ut.ili~in~ a generally s.m.ilar construction, mounts an optical bundle 205 connected throu~h coupling 206 and haviny an L~shaped terminal, not shown, with a optical face 210. Module 180 also mounts a 5 vacuum support air tube 215 coupled through a quick disconnect couplin~3 216 to the same vacuum source supplying vacuum ~ir tube 19~.
Bundle 185 serves the same function as bundle 75 of the first form o~ the first embodiment and bundle ~05 serves the same function as bundle 80 of the first form of the Eirst emhodiment.
In~using the strap assembly 140 o~ the second form of the first embodiment, the required optical transrnission and vacuuln circuits are esta~lished and optical gel is applied to the 15 respective optical faces 190, 210. The strap lS0 is then suitably secured 50 as to place the respective housing front faces, e.g., ~aces 192, and respective optical faces 190, 210 in suitable bofly contact and also to place the respective ~vacuum supplied recesses 200 directly over and surrounding the body surfaces serving as points of light entry and exit.
Where increased vacuum effect is desired beca~lse of the nature of the body surface to which the inven-tion apparatus is being attached, the alternative module constr~lction illustra-ted in Figure 13 increases the vacuum e~fect and thereby increases the vacuum assisted securement to the body. Thus, in conjunc-tion with the resilient pressing eEfect .afforded by strap 150 and module support 155, there is provided an improved auxiliary vacuum assisted means for ohtaining improved light shielding and securement of the strap assembly 140. As with the first form of the first embodiment, t~e resilient and deormable character of the material chosen for module support 155 allows the thickness of the module suppor-t 155, as v.iewed in Figure 8, to contract when strap 150 is applied and suitably secured by use of the appropriate "Velcro" straps 220-223. With the optical module support 155 resiliently compressed in this fashion, with an optical gel applied to the respective optical faces 190, 210 and with the appropriate vacuum applied to the respective modules 170, 180, i-t can be s ~ s: . .

\
-~6-seen that a substantially improved and efEective optical coupling is secured. Further, as with the first Eorm oE the first embodiment, the optical modules 170, 180 can be pre-Eabricated and installe~ in a~propriate molded recesses in module support 155 as a subasset.nbly for quick connection to the li~ht source, light processing and vacuum equipment.
Further, annular, double-sided, pressure-sensitive tapes, as previously described, may be employed around the respective optical faces to en~ance securement when not usincJ the vacuum.
However, the vacuum securement is particularly aavantageous when measuring wet sur~aced portions of the body as for example in open heart surgery.
While not illustrated; it will also be appreciated that the illustrated optical modules may be formed with continuous ~iber bundles leading to the light source and processing circuitry so as to avoid the use of the illustrated quick disconnect couplings.
Also to be recognized is that ~he described vacuum arrangement lends itself to use with optical modules fitted with photo-detector, i.e.~ electronic type light sensors as in prior Pat~nt 40321,930. Thus, a new and versatile means oE
securement by vacuum is provided.
Another feature to be recognized in the illustrated embodiments as best seen in reference to Figure 2 is that the thickness T of the module support material is purposely made larger than the overall thickness X (Figure 4) of ~he optical modules. This allows the module support foam material 35 to effectively slide on the respective optical modules and be slightly compressed during application to the body and which assists in holding the respective modules properly positioned.
Having descibed in reference to Figures 1-14 three forms of the first embodiment in which an elongated strap-type -securing means is employed, ~he description refers next to the second embodiment as ill~strated in Figures 15-30 in which the optical module-socket type construction is retained but in a form not requiring use of a strap as the securing means.
As background for the description related to the second er~bodiment, it is noted tha-t in some surgical procedures in c . I

which it is desirable to monitor oxygen sufficiency in the b~ain, the procedure requires that the patient's ~ead be tilted backward for admitting various instrum~nts or substances in the t~roat or such bacXward he~d tilting may simply be desired surgical or rnedic~l procedure. In o-ther medical or surgical procedures where oxygen sufficiency in the brain is desirably monitored, the patient's head may not require tilting. Particularly when it is necessary t~at t'he patient's head be tilted backward, it has been found that the releaseable strap arrangement descrihed in Fi~ures 1-14 has certain disadvantages and caution is re~uired to see that the light source-detector assembly is not dislodged or mispositioned when the patient's head is tilted backwardO
However, at other times when the patient's head is not til~ed backward, the strap securing arrangement oE -the first embodimen-t as in Figures 1-14 has proven satisfactory. Thus, in tlle structure oE the second embodiment of the present invention an improved light source-detector body mounting -assembly has been provided in which all of t~e desired characteristics previously achieved in the first embodiment have been retained while at the same time providing an improved mounting assembly especially adap-ted or use on -the head during monitoring of the brain and which adap-ts to the patient's head being either tilted backward or not as required by the medical or surgical procedure involved.
Light source and light detector modules are used in bo-th the first and second embodiments. In the second embodiment there is provided for each light source and light detector module a socket device ada~ted -to receive the module and by means oE radially extending flexible tabs to be adhesively secured to the body at the place of attachment using double-sided adhesive tape. The length of the socket tabs allows the pa,ir of sockets holding the respective light source-light detector modules to be accurately spaced apart as required for practicing the op-tical monitoriny -techniques of the prior patents. The improved moun-ting apparatus of the invention according to the second embodiment also provides Eor a flexible light shielding pad to be adhesively secured to the 2~ ~

body 50 as to cover the socket tab~ and allow the remainin~
portions o the sockets to protrude outwardly frorn ~he pat~ and the appropriate interconnected optical cables to lea~l Eroln ~he pad to ~he light source and processing circuitry of the related prior patents. Once the optical Inodules and their respective sockets have been appropriateLy mounted ana have ~een suitably covered by the men-tioned light shielding pad, an additional somewhat larger second light shiel~ing pad i9 placed over the first pad so as to cover both -the Eirst light shielding pad, the soc~ets and those portions of the optical cables leading rom the respective optical modules in the sockets. The second light shielding pad is adhesively sacured to the body at the pad's periphexal edges employing double-sided adhesive tape~ As a final light shielding procedure, a flexible light impervious cape such as previously disclosed in reference to the first embodiment is placed over that portion of the patient's body on which the mentioned optical modules, sockets and light shielding pads have been mountea so as to ~urther .shield both the light source and modules from ambient light.
- With specific reEerence to Figures 15-30, the improved light source detector assembly 320 according to the second embodiment of the invention comprises a flexible, light shielding adhesively secured base support pad 330, a pair of module sockets 335, 336, a light source module 350, a light aetector module 360, an auxiliary light shielding pad 340 and finally an overall light shielding drape 345.
Base support pad 330 is preferably ormed of a tightly constructed non-elastic, black coated fabric such as found, for exarnple, in black coated Naugahyde abric used for automobile seats, upholstery, and the like , and should preferably provide sufficient flexibility to conform to the shape of the head or other part oE the body of the human or animal subject being monitored. Additionally, all surfaces o pad 330 should preferably be black in color to assist in absorbing the extraneous photon energy proximate to the observation area. Positive securement of pad 330 to the body surface i~ facilitated by employment o~ a suitable pressure ": I

sensi~ive adhesive 338 over the entire surface ~E pad 330 which is adhered to the ~ody. A removable cover s~leet over a~hesive 33~ is desirable.
The module sockets 335, 336 are preferably formed of a molded plastic ma~erial which is both resilien~ and defor~n~hle to a degrPe suited to t~e invention as described. Each module socket 335, 336 provides a hollow, resilent wall housing molded with an open base end and closed upper encl so as to snugly receive a respective light source module 350 or light detector module 360. In a preEerred orm, the inner diameter D and inner length L of sockets 335, 336 are of standard size as are the outer diameter D' and outer length L' of modules 350, 360. As best illustrated in Figures 15, 22, and 26, each module socket 335, 336 will also be noted as having an open slot 337 for receiving the respective optical cables 351, 361 leading from the respective optical modules 350, 360. Each respective socket 335, 336 is thus assembled with a respec~ive optical module 350 or 360 as illustra-~ed by way of example in Figures 25 and 26 with respect to khe assembly of -the socket 336 with the light detector module 360.
Optical cables 351, 361 made up of bundles of optical fibers may lead directly to the light source and processing circuitry 355 of the prior related patents with no intervenirlg optical coupling and thereby minimize light loss.
Alternatively, it is sometimes desirable that means be provided enabling the invention assembly 320 to be quickly optically coupled and uncoupled at the body. ~or this situation, quick connect-disconnect o,ptical couples 352, 353 are provided.
~ach socket 335, 336 is provided ak the open base end with three radially extending thin, flexible tabs 339 preferably of uniform size and of uniform length T. A
double-siaed pressure sensitive tape 341 is secured to the bottom of each respective tab 339 and is used as a means of securing the respective socket 335 or 336 to the body surface.
Removable covering strips may be employed to protect the adhesive material prior to installation. Additionally, as later reEerred to in connection wi-th Fiyures 29 and 30 it will ~3~

-~o--be noted that the critical distance M between -the liyht source module 350 and light detector mo~ule 360 can b2 est~bli~hed by overlapping a pair of tabs 339 and using the length T as a locating device as best illustratecl in Figure ~. Pad 330 is ~orrned with two sli-ts 331, 332 leadin~ from socket holes 333, 334 and spaced apart by ~he same critical distance M.
Distance M represents t~le same critical distance previously designated as ais~ance S in Figures 1 and 7. Thus, the space ~etween the slits 331, 332 can also be used as a spacing re~erence. Slits 331, 332 also facilita-te asse~bly of pad 330 on the respeetive sockets 335, 336 after the respec~ive optical. modules 350, 360 have been fully nes-ted in their respective sockets 335, ~36 by allowing the respec~ive outgoing optical cables 351, 361 secured through the respective quick disconnect couplings 35~, 353 to pass tllrough slits ~,31, 332 and over pad 330 during afisembly of pad 330 on sockets 335, 336.
While serving ~ifferent functions, optical modules 350 and 360 are basically of similar size and construction and will be more fully described in reference to Fi~ures 16-21.
- Module 350, by way of example, comprises a hollow, eircular-shaped housing 370 having a back cover plate 371 and a flat front face 372 formed with a central aper-ture 373. The fiber bundle 351 couples through quick disconnect optical couplin~ 352 and terminates with a right angle shaped terminal end 379 having a slightly pro~ruding portion with a ground optical faee 3~0 located in the aperture 373. The void within housing 370 surrounding the right angla shaped terminal end 379 is filled with an epoxy or similar hard-setting compound to facilitate securement of the terminal end 379 within ~ousing 370 and back cover pla-t~ 371 is suitably glued or otherwise secured in place after such assembly.
Terminal end 379 of iber bundle 351 provides both a near-infrared light source terminal and a corrective detector terminal with seleeted fibers being employed for bringing light to the point of light entry and other randomly dispersed selected ~ibers being employed for collecting light reflected back directly from or near (1-3 mms) t~e point of light entry.

, ~. , , " - , , . ~-- ;-The manner in which such corrective and measured lighl ~ourcesoperate is explained in the related prior pa-tents.
Module 360, as previously stated, employs a similar construction to that o~ module 350 and moun-ts fiber bundle 361 connected throu~ ~uick disconnect optical couplin~ 353 and having ~ ri~ht angle shaped terminal end 382 with a slightly protruding portion having a ground o~tical face 3~3. Bundle 361 is used as a means ~or collecting the measured reflected light for processin~, as fully explained in the related prior patents. Further, during the light measuring operation, modules 350 and 360 are mounted in their respective module sockets 335, 336 and are positioned on ~l~e body so as to maintain uniform the spacin~ M within the limits discussed in the related prior patents.
Shielding of ambient li~ht is deemed critically important especially when metabolic trends are being monitored and discrete changes are siynificant thou~n small in value. Thus, when the respective modules 350, 360 have been assernbled in the respective sockets 335, 336 and are mounted as depicted in Figure 15 with pad 330 adhesively secured over the respecti~e ~ocket tabs 339, an additional protective shielding is provided by employing the auxiliary pad of light shieldin~
material 340 which is provided with double-side~ adhesive tape 344 such that pad 340 can be firmly secured and provi~e adequate light shieldin~3 over t~e respective modules 350, 360 -assembled in their respective sockets 335, 336 as depicted in Figure 15. The corresponding optical cable~ 351, 361 are led out under pad 340 and are preferably wrapped with a black felt ~trip 348 at the point where the cables exit from beneath pad 340 to provide additional shielding. A den~e, black, highly 1exible, hard neoprene rubbe~ sheet of 1/64" thickness has been found suitable for use in making pad 340~
As ano-ther a~pect of the present invention, a pair of thin, ~ouble-sidea, annular-shaped, pressure sensitive

3$ adhesive tapes 400, 401 are employed on the respec-tive modules 350, 360 and are used to assist in providing the desired ambient light shieldin~ around the respective optical Eaces 380, 383. Tapes 400, 401 are preforme~ in the shape .1 , i , , ~ - :

illustrated in ~igure 14 and typically have ralnovable a~hesive pro-tective covering whic}-, aEter removal, allows the respec-tive tapes 400, 401 to be attached on one sicle to -the respective moclules 350, 360 while leaving the opposite adhesive surfaced side of t~e respective tapes ~00, 401 exposecl for securing to the respective body sur~aces opposite the respective optical faces 380, 3B3.
In using the invention assem~ly 320, an optical ~el is applied ~o each optical face 380, 383 and the respective annular adhesive tapes 400, 401 are installed around the respective optical Eaces 380, 383. The respective modules 350, 360 are then snugly ~itted into their respective sockets 335, 336. In order to obtain the desired spacing M between the light source module 350 and the .light detector module 360, the socket tabs 339 may be oriented prior to being adhered to the b~dy surface as in Figure 29 such tha-t the socket tab length T maintains the correct distance M. In this moc~e oE
installation ater the optical modules 350, 360 have been snugly fitted into their respective socXets 335, 336 as illu~trated in Figures 25-26 for module 360 as an example, the respective covers for adhesive strips 3~1 may be removed from the socket tabs 339 and from annular tapes 400, 401 and -the modules 350, 360 adhered to the body in the orientation illustrated in Figure 29. After this step, the adhesive cover for the adhesive on pad 330 is removed and pad 330 is next installed over the assembled optical module~ 350, 360 and sockets 335, 336 utilizing t~e slits 331, 332 to position the op-tical cable~ 351, 361 extending out over ~ad 330 as seen in Figures 15 and 30.
In another installation mode after the respactive optical modules 350, 360 are snugly fitted into the respective sockets 335, 336 the sockets are installed in pad 330 as illustratea in Figure 30. The spacing betwean the sli-ts 331, 332 thus establishes the desired spacing M required during the measuring operation. In this mode of installation, the covers for the adhe~ive on adhesive tapes 341 on socket tabs 339, tlle covers on the adhesive on annular tapes ~00, 401 and the covar ~or the adhesive on pad 330 may be r~moved after tha respective ~3 ~
~23-sockets 335, 336 with ~he res~ective modules 350, 360 have been assembled in ~he manner of Figure 30. The entire pad-socket module assembly illustrated in Figure 30 can then be adhered to t~e hody utiliæing the adhesive surEaces oE t~e optical tapes 400, 401, the adhesive surfaces on ~he socke-t tabs 339 and -the adhesive sur~ace provided on the pad 330.
The auxiliary pad 340 is then next installe~ in the manner previously described following which a suitable ligh-t shielding cape 345 is draped over -the head and over those portions of the optical cabling proximate t~e assembly 320 to provide additional ambient light shielding.
From the foregoing description of the second embodiment of the invention, various advantages over the light source-detector mounting arrangements set forth in the prior patents will become evident. A major advantage resides in the ability to secure the assembly 320 to the body, particularly to the head for brain monitoring, without requiring the use of a strap as in the first embodiment. Thus, i it becomes i- ` -necessary to tilt the head backward during the 6urgical or medical procedure, this can be accomplished with the structl~re of the second embodiment as illustrated in Figure 15 without dislodging the monitoring assembly 320. Alternatively, when the head or other portion of the body being monitorea is not required to be tilted, the described invention apparatus lenas itself to this application Inode as does the first embodiment.
The respective sockets 335, 336 may be made of a suitable plastic and thus may be forme~ as relatively inexpensive single end-use components. ~dditiona:Lly, pad 330 may also be a disposable single end-use component as well as the auxiliary pad 340. Thus, by being able to provide these operating components in a form adapted to disposable, single end-use, subs-tantial expenae is saved with regard to washing and sterilizing the invention apparatus following a surgical or medical procedure.
The invention apparatus also achieves a significant advance in light shielding in being able to utilize ~he combined shielding characteristics of -the annular tapes 400, ~01 which surround the respective optical faces 380, 383 on . ,' ~, -2~-modules 350, 360 in conjunction with t~e shielding properties oE pad 330 which can be ~ightly secured by me~ns of t~
- adhesive 338 on the surface oE pad 330. Additional shielding is, of course, provid~d by -the auxiliary shielding pad 340 u~ilizin~ tlle adhesive s-trips 344.

. .. j, , , . ; .

Claims (11)

What is claimed is:

1. In a spectrophotometric measuring apparatus for measuring in situ, in vivo, non-invasively, atraumatically, harmlessly, rapidly and continuously a selected activity of a selected portion of the body where such activity bears a measurable relation to an absorption characteristic of the selected portion for a particular wavelength of light, said apparatus being of the type having:
(a) light source means including:
(i ) a plurality of near-infrared light sources located external of the body and having light emissions of different wavelengths in a selected spectral range and of an intensity below the level damaging to the body and said selected portion but sufficient to be detectable by a light sensor after .
transmission through an optical transmission-reflectance path including said selected portion thereof and extending between selected points of light entry and exit spaced several centimeters apart and located on contiguous skin surface areas of the body and after scattering in and reflectance from said selected portion along said path; and (ii) means operatively associated with said light sources to produce emissions representing at least one measuring wavelength and at least one reference wavelength within said spectral range for transmission along said path to said selected portion, said measuring wavelength being selected such that said selected portion exhibits a selected absorption therefor, the extent of which is dependent upon the specific state of the activity being measured;

(b first optical cable means providing a bundle of optical fibers with selected fibers connected for receiving and transmitting the output light emissions of said light. sources at said measuring and reference wavelengths to a selected point of light entry proximate said body;
(c) second optical cable means providing a bundle of optical fibers connected for receiving deeply penetrating light emissions reflected and scattered to a selected said point of light exit from said selected portion of said body and transmitting such exiting light emissions to a processing means;
(d) processing means operatively associated with said light source means adapted to produce from the outputs of said first and second optical cable means an electrical output signal representing the difference in absorption of said measuring and reference wavelengths by said selected body portion as a function of the state of said activity and further adapted to convert said electrical output signal to a signal providing a substantially continuous and rapid measure of said activity;
the improvement comprising:
(e) a detachable, body mountable apparatus operatively associated with said light source, first and second optical cable and processing means comprising:
(i) a flexible, elongated support member adapted to be releasably secured to the body proximate a said selected portion of the body having a selected set of said spaced light entry and exit points, to provide ambient light shielding over said light entry and exit points and to conform to the curvature and shape of the body at the location (ii) module mounting structure adapted to be light shielded and held by said support member against said selected portion of the body and to deform in shape in correspondence with the curvature assumed by said support member when secured to the body;
(iii) a first preformed optical module mounted in said structure and providing a hollow housing enclosing first light guide means formed by a bundle of optical fibers optically coupled to said first optical cable means and having a first optical light emitting face centrally positioned in an outer face of said housing and adapted to be mated in a substantially pressed fit relation with said selected point of light entry utilizing selected fibers of said bundle for entry of light in selected wavelengths to be transmitted, deeply reflected and scattered along said path and to said selected portion of the body; and (iv) a second preformed optical module mounted in said structure and providing a second hollow housing enclosing second light guide means formed by a bundle of optical fibers optically coupled to said second optical cable means and having a second optical light receiving face centrally positioned in an outer face of said second module housing and adapted to be mated in a substantially pressed fit relation with said selected point of light exit spaced said several centimeters from said point of light entry for receiving and transmitting deeply penetrating light emissions reflected and scattered to said selected point of light exit from said selected portion of said body.

2. In an apparatus as claimed in claim 1 wherein each said optical module includes openings in the respective outer faces of the respective housings thereof surrounding the respective optical faces thereof and means communicating said openings to a vacuum source whereby securement of said optical faces to the respective points of light entry and exit is enhanced by a vacuum assisted pull on the skin surrounding said points.

3. In an apparatus as claimed in claim 1 wherein said module mounting structure is detachably secured to said support member.

4. In a spectrophotometric measuring apparatus as claimed in claim 1 wherein:
(a) said module mounting structure comprises:
first and second socket structures, each providing a hollow wall structure having an open base end and flexible tab members extending radially outward from said base end, said first socket structure being adapted to receive in snug fit relation said first optical module housing with an external optical cable connected portion of the fiber bundle associated with said first optical module leading from the wall of said first socket structure and the said second socket structure being adapted to receive in snug-fit relation said second optical module with an external optical. cable connected portion of the fiber bundle associated therewith leading from the wall of said second socket structure, and including adhesive means on the bottom surfaces of said tab members enabling said tab member to be secured to the body in laterally spaced relation whereby to secure said optical modules in the same spaced relation; and (b) wherein said elongated flexible support member comprises:
a flexible light shielding pad having one adhesive surfaced side and being adapted to be fitted over said socket structures with said modules fitted therein and in a manner enabling said adhesive-surfaced side to be adhesively secured to the body and in a manner enabling said tab members to be covered and the respective optical faces of said modules to be light shielded by said adhesively faced side of said panel with the respective optical cabling connected to said modules overlying the opposite side of said pad.

S. In a spectrophotometric measuring apparatus as claimed in claim l including at least one auxiliary ambient light-sheilding cover adapted to overlie said support member during operation of said apparatus.

6. In a spectrophotometric measuring apparatus as claimed in claim l wherein:
(a) said first optical cable means bundle of optical fibers include other selected fibers connected for transmitting deeply penetrating light emissions reflected directly back from any skin bone and tissue at or within a few millimeters of said selected point of light entry to a processing means;
(b) said processing means electrical output signal is corrected for changes in blood volume of said skin, bone and tissue during the measuring cycle; and (c) said first preformed optical module bundle of optical fibers include other selected fibers of said bundle for receiving light emissions reflected directly back from any skin bone and tissue at or within a few millimeters of said selected point of light entry.

7. In a spectrophotometric measuring apparatus as claimed in claim 4 wherein said shielding pad comprises a flexible light shielding pad having a pair of apertures formed to receive said socket structures in a predetermined spaced relation and with slit portions of said pad connecting said apertures to an outer edge thereof thereby enabling said shielding pad to be fitted over said tab members while allowing the optical cables

Claim 7 continued....
associated with said modules to lead away from said shielding pad over and above the outer surface thereof.

8. In a spectrophotometric measuring apparatus as claimed in claim 4 including at least one auxiliary ambient light-sheilding cover adapted to overlie said first shielding pad during operation of said apparatus.

9. In a spectrophotometric measuring apparatus as claimed in claim 4 wherein said first and second optical module housings are of similar size and cylindrical shape, said socket hollow wall structures are of similar size and cylindrical shape so as to provide hollow cylindrical receptacles mating in a snug fit said optical module housings and wherein said socket hollow wall structures are slotted for passing therethrough the respective fiber bundles leading from the respective said modules and each said socket hollow wall structure has a closed end wall opposite the base end thereof.
10. Spectrophotometric measuring apparatus for measuring a selected activity of a selected portion of a human body where such activity bears a measurable relation to an absorption characteristic of the selected portion for a particular wavelength of light, including in combination:
(a) first optical cable means providing a bundle of optical fibers with selected fibers connected for receiving and transmitting the output light emissions of light sources at measuring and reference wavelengths to a selected point of light entry on said selected portion of said body and other selected fibers connected for receiving and transmitting light emissions reflected directly back from said selected point of light entry to a processing means;

Claim 10 continued...
(b) second optical cable means providing a bundle of optical fibers connected for receiving and transmitting light emissions reflected and scattered to a selected point of light exit on said selected portion of said body to a processing means;
(c) a first preformed optical module comprising a molded cylindrical hollow housing enclosing first light guide means formed by a right-angle-shaped bundle of optical fibers optically coupled at one end to said first optical cable means and at the opposite end having a first optical light emitting face centrally positioned in an outer face of said housing and adapted to be mated in a substantially pressed fit relation with said selected point of light entry;
(d) a second preformed optical module comprising a second molded cylindrical hollow housing of the same size as said first housing and enclosing second light guide means formed by a right-angle-shaped bundle of optical fibers optically coupled at one end to said second optical cable means and at the opposite end having a second optical light receiving face centrally positioned in an outer face of said second module housing and adapted to be mated in a substantially pressed-fit relation with said selected point of light exit;
(e) first and second socket structures of similar size, each being molded as an integral internally-hollow structure having a cylindrical side wall with an open base end and an opposite closed end, a slot in the wall structure for passing therethrough a respective optical fiber bundle leading from a respective said module, and a

Claim 10 continued...
plurality of thin flexible tab members of uniform size and length extending radially outward -from and circumferentially spaced on said base end, said first socket structure being adapted to receive in snug-fit relation said first optical module housing with the optical cable connected end portion of the fiber bundle associated with said first optical module passing through the slot of said first socket side wall and the said second socket structure being adapted to receive in snug-fit relation said second optical module with the optical cable connected portion of the fiber bundle associated with said second optical module passing through the slot of the said second socket side wall, and including adhesive means on the bottom surfaces of said tab members enabling the tab members of said first socket structure to be secured to the body in laterally spaced relation with respect to the tab members of the second socket structure whereby to secure said optical modules in corres-pondingly-spaced relation; and (f) a flexible light-shielding pad having one adhesive surfaced side, having a pair of apertures formed to receive said socket structures in a pre-determined spaced relation, having slit portions of said pad connecting said apertures to an outer edge thereof thereby enabling said shielding pad to be fitted over said tab members while allowing the optical cables associated with said modules to lead away from said shielding pad over and above the outer surface thereof and in a manner enabling said adhesive surfaced side to be adhesively secured to the body and the respective optical faces of said modules to be light shielded by said adhesively faced side of said panel.

11. A spectrophotometric measuring apparatus as claimed in claim 10 wherein said plurality of tab members comprise three said tab members circumferentially equally spaced on said base end and the length of said tab members corresponds to a length of measure by which said pre-determined spaced relation may be established.