Document:

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                                                                  EXHIBIT 10.52

                           STOCK REPURCHASE AGREEMENT

         This Stock Repurchase Agreement is entered into as of this 15th day of
March, 2002, by and among CTI, INC., a Tennessee corporation (the "Company"),
and S.I.E. NETHERLANDS B.V. (the "Stockholder").

                                   BACKGROUND

         Stockholder owns 704,476 shares of Common Stock of the Company (the
"Shares") and the Company is willing to repurchase the Shares for the Purchase
Price (as defined below) upon the terms and subject to the conditions set forth
in this Agreement.

                                    AGREEMENT

         NOW, THEREFORE, the Stockholder and the Company agree as follows:

                                    SECTION 1
                          REPURCHASE AND SALE OF SHARES

         1.1      Repurchase and Sale of Shares. On the terms and subject to the
conditions set forth in this Agreement, the Company agrees to purchase from the
Stockholder and the Stockholder agrees to sell, transfer, convey and deliver to
the Company 704,476 shares of Common Stock of the Company at a price equal to
$7.50 per share.

         1.2      Payment for Shares. The total purchase price for the shares
shall be Five Million, Two Hundred Eighty Three Thousand, Five Hundred and
Seventy United States Dollars ($5,283,570) (the "Purchase Price"). Upon receipt
of the Purchase Price, the Stockholder irrevocably appoints any officer,
employee or agent of the Company as his attorney to cancel or transfer the
Shares on the books of the Company with full power of substitution.

                                    SECTION 2
                         REPRESENTATIONS AND WARRANTIES

         2.1      Representations and Warranties of the Stockholder. The
Stockholder represents and warrants to the Company as follows:

                  2.1.1    Power and Authority. The Stockholder has the power
and authority to execute and deliver this Agreement and consummate the
transactions contemplated hereby.

<PAGE>

                  2.1.2    Validity; Enforceability. This Agreement and all
other instruments or documents executed by the Stockholder in connection
herewith have been duly executed by the Stockholder, and constitute legal, valid
and binding obligations of the Stockholder, enforceable in accordance with their
respective terms.

                  2.1.3    No Encumbrances, Etc. The Stockholder is the owner of
record of all right, title and interest (legal and beneficial), free and clear
of all liens, in and to the Shares. Upon delivery of certificates representing
the Shares to be sold by the Stockholder to the Company hereunder and payment
therefor pursuant to this Agreement, good, valid and marketable title to such
Shares, free and clear of all liens, encumbrances, equities, claims, liabilities
or obligations, whether absolute, accrued, contingent or otherwise, will be
transferred to the Company.

                  2.1.4    Knowledge; Access. The Stockholder has such knowledge
and experience in financial and business matters and has been furnished access
to such information and documents concerning the Company that it is capable of
evaluating the merits and risks of accepting the Purchase Price in exchange for
the Shares and the other terms and conditions of this Agreement. The Stockholder
has had an opportunity to ask questions and receive answers concerning the terms
and conditions of this repurchase and to obtain additional information regarding
the Company's plans and future prospects.

                  2.1.5    Accredited Investor Status. The Stockholder is an
"accredited investor" as such term is defined in Rule 501(a) of Regulation D
promulgated under the Securities Act of 1933, as amended.

         2.2      Representations and Warranties of the Company. The Company
represents and warrants to the Stockholder as follows:

                  2.2.1    Power and Authority. The Company has the power and
authority to execute and deliver this Agreement and consummate the transactions
contemplated hereby.

                  2.2.2    Organization and Qualification. The Company is a
corporation, duly organized, validly existing and in good standing under the
laws of the jurisdiction of its organization.

                  2.2.3    Validity; Enforceability. This Agreement and all
other instruments or documents executed by the Company in connection herewith
have been duly executed by the Company, and constitute legal, valid and binding
obligations of the Company, enforceable in accordance with their respective
terms, except as enforceability may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium or similar laws affecting the enforcement
of creditors' rights generally and general principles of equity (whether
considered in an action at law or in equity).

                                      -2-
<PAGE>

                                    SECTION 3
                                  MISCELLANEOUS

         3.1      Notices. In order to be effective, any notice or other
communication required or permitted hereunder, shall, unless otherwise stated
herein, be in writing and shall be transmitted by messenger, delivery service,
mail or telecopy, as specified below:

                                    If to the Company:

                                    CTI, Inc.
                                    810 Innovation Drive
                                    Knoxville, Tennessee 37932
                                    Telecopier: (865) 218-3000
                                    Attention:  Dr. Terry D. Douglass

                                    with a copy (which shall not constitute
                                    notice) to:

                                    Alston & Bird LLP
                                    One Atlantic Center
                                    1201 West Peachtree Street
                                    Atlanta, Georgia  30309-3424
                                    Telecopier: (404) 881-4777
                                    Attention:  R. Gregory Brophy

                                    If to the Stockholder:

                                    MeesPierson Trust B.V.
                                    SIE Netherlands B.V.
                                    Herengracht 548
                                    1017 CG Amsterdam, Netherlands
                                    Telecopier: [31206258279]
                                                 -----------
                                    Attention:  Managing Director

or at such other address as a party shall designate in a written notice to the
other parties hereto given in accordance with this Section 3.2. All notices and
other communications shall be effective (a) if sent by messenger or delivery
service, when delivered, (b) if sent by mail, five (5) days after having been
sent by certified mail, with return receipt requested, or (c) if sent by
telecopier with receipt acknowledged, when sent.

         3.2      Successors and Assigns. This Agreement shall be binding upon
and inure to the benefit of the parties hereto and their respective permitted
successors and assigns.

         3.3      Entire Agreement, Amendment. This Agreement constitutes the
entire agreement between the Company and Stockholder with respect to the
transactions contemplated hereby and thereby; supersedes all prior or
contemporaneous negotiations, communications, discussions and correspondence
concerning the subject matter hereof;

                                      -3-

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and may be amended or modified only with the written consent of the Company and
the Stockholder.

         3.4      Severability of Provisions. If any provision of this Agreement
shall be prohibited by or invalid under applicable law, such provision shall be
ineffective only to the extent of such prohibition or invalidity without
invalidating the remainder of such provision or any remaining provisions of this
Agreement, and the parties shall use their respective best efforts to negotiate
and enter into an amendment to this Agreement whereby such provision will be
modified in a manner that is consistent with the intended economic consequences
of the invalid provision and that, as modified, is legal and enforceable.

         3.5      Governing Law. This agreement shall be governed by and
construed in accordance with the internal laws of the State of Tennessee without
giving effect to any choice of law or conflict, provision or rule (whether of
the State of Tennessee or any other jurisdiction) that would cause the laws of
any jurisdiction other than the State of Tennessee to be applied.

         3.6      Counterparts. This Agreement may be executed in separate
counterparts, either of which, when so executed, shall be deemed to be an
original and both of which, when taken together, shall constitute but one and
the same agreement.

         3.7      Survival. The representations, warranties, covenants and
agreements made herein shall survive the execution and delivery of this
Agreement and the consummation of the transactions contemplated hereby,
notwithstanding any investigation made by either party.

         3.8      Further Assurances. Each party shall at any time and from time
to time after the date hereof take whatever actions the other party or its
affiliates or agents reasonably request to effectuate, record, evidence or
perfect its transfer of the Shares to the Company pursuant to this Agreement or
to otherwise effectuate or consummate any of the transactions contemplated
hereby.

                                      -4-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed the day and year first written above.

                                     CTI, INC.

                                     By:      /s/ Terry D. Douglass
                                        --------------------------------------
                                          Terry D. Douglass
                                          President

                                     S.I.E. NETHERLANDS B.V.

                                     By:      /s/
                                        --------------------------------------
                                          Name:        MeesPierson Trust B.V.
                                               -------------------------------
                                          Title:       Managing Director
                                                ------------------------------

                                      -5-<PAGE>

                                                                  EXHIBIT 10.53

                           STOCK REPURCHASE AGREEMENT

         This Stock Repurchase Agreement is entered into as of this 15th day of
March, 2002, by and among CTI, INC., a Tennessee corporation (the "Company"),
and SEIKO INSTRUMENTS, INC. (the "Stockholder").

                                   BACKGROUND

         Stockholder owns 880,592 shares of Common Stock of the Company (the
"Shares") and the Company is willing to repurchase the Shares for the Purchase
Price (as defined below) upon the terms and subject to the conditions set forth
in this Agreement.

                                    AGREEMENT

         NOW, THEREFORE, the Stockholder and the Company agree as follows:

                                    SECTION 1
                          REPURCHASE AND SALE OF SHARES

         1.1      Repurchase and Sale of Shares. On the terms and subject to the
conditions set forth in this Agreement, the Company agrees to purchase from the
Stockholder and the Stockholder agrees to sell, transfer, convey and deliver to
the Company 880,592 shares of Common Stock of the Company at a price equal to
$7.50 per share.

         1.2      Payment for Shares. The total purchase price for the shares
shall be Six Million, Six Hundred Four Thousand, Four Hundred and Forty United
States Dollars ($6,604,440) (the "Purchase Price"). Upon receipt of the Purchase
Price, the Stockholder irrevocably appoints any officer, employee or agent of
the Company as his attorney to cancel or transfer the Shares on the books of the
Company with full power of substitution.

                                    SECTION 2
                         REPRESENTATIONS AND WARRANTIES

         2.1      Representations and Warranties of the Stockholder. The
Stockholder represents and warrants to the Company as follows:

                  2.1.1    Power and Authority. The Stockholder has the power
and authority to execute and deliver this Agreement and consummate the
transactions contemplated hereby.

<PAGE>

                  2.1.2    Validity; Enforceability. This Agreement and all
other instruments or documents executed by the Stockholder in connection
herewith have been duly executed by the Stockholder, and constitute legal, valid
and binding obligations of the Stockholder, enforceable in accordance with their
respective terms.

                  2.1.3    No Encumbrances, Etc. The Stockholder is the owner of
record of all right, title and interest (legal and beneficial), free and clear
of all liens, in and to the Shares. Upon delivery of certificates representing
the Shares to be sold by the Stockholder to the Company hereunder and payment
therefor pursuant to this Agreement, good, valid and marketable title to such
Shares, free and clear of all liens, encumbrances, equities, claims, liabilities
or obligations, whether absolute, accrued, contingent or otherwise, will be
transferred to the Company.

                  2.1.4    Knowledge; Access. The Stockholder has such knowledge
and experience in financial and business matters and has been furnished access
to such information and documents concerning the Company that it is capable of
evaluating the merits and risks of accepting the Purchase Price in exchange for
the Shares and the other terms and conditions of this Agreement. The Stockholder
has had an opportunity to ask questions and receive answers concerning the terms
and conditions of this repurchase and to obtain additional information regarding
the Company's plans and future prospects.

                  2.1.5    Accredited Investor Status. The Stockholder is an
"accredited investor" as such term is defined in Rule 501(a) of Regulation D
promulgated under the Securities Act of 1933, as amended.

         2.2      Representations and Warranties of the Company. The Company
represents and warrants to the Stockholder as follows:

                  2.2.1    Power and Authority. The Company has the power and
authority to execute and deliver this Agreement and consummate the transactions
contemplated hereby.

                  2.2.2    Organization and Qualification. The Company is a
corporation, duly organized, validly existing and in good standing under the
laws of the jurisdiction of its organization.

                  2.2.3    Validity; Enforceability. This Agreement and all
other instruments or documents executed by the Company in connection herewith
have been duly executed by the Company, and constitute legal, valid and binding
obligations of the Company, enforceable in accordance with their respective
terms, except as enforceability may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium or similar laws affecting the enforcement
of creditors' rights generally and general principles of equity (whether
considered in an action at law or in equity). The terms of this Agreement and
the underlying transaction comply with all applicable laws of the United States
of America and of any applicable state thereof and no consent, approval, order
or

                                      -2-
<PAGE>

authorization of, or registration, qualifications, designation, declaration
or filing with, any federal, state or local governmental authority on the part
of the Company is required in connection with the consummation of the repurchase
of shares contemplated by this Agreement.

                                    SECTION 3
                                  MISCELLANEOUS

         3.1      Notices. In order to be effective, any notice or other
communication required or permitted hereunder, shall, unless otherwise stated
herein, be in writing and shall be transmitted by messenger, delivery service,
mail or telecopy, as specified below:

                                    If to the Company:

                                    CTI, Inc.
                                    810 Innovation Drive
                                    Knoxville, Tennessee 37932
                                    Telecopier: (865) 218-3000
                                    Attention:   Dr. Terry D. Douglass

                                    with a copy (which shall not constitute
                                    notice) to:

                                    Alston & Bird LLP
                                    One Atlantic Center
                                    1201 West Peachtree Street
                                    Atlanta, Georgia  30309-3424
                                    Telecopier:  (404) 881-4777
                                    Attention:   R. Gregory Brophy

                                    If to the Stockholder:

                                    Seiko Instruments, Inc.
                                    1-8, Nakase Mihama Ku
                                    Chiba-shi, Chiba 261-8507
                                    JAPAN
                                    Telecopier: +81-43-211-8027
                                    Attention:  Mr. Akio Irie

or at such other address as a party shall designate in a written notice to the
other parties hereto given in accordance with this Section 3.2. All notices and
other communications shall be effective (a) if sent by messenger or delivery
service, when delivered, (b) if sent by mail, five (5) days after having been
sent by certified mail, with return receipt requested, or (c) if sent by
telecopier with receipt acknowledged, when sent.

         3.2      Successors and Assigns. This Agreement shall be binding upon
and inure to the benefit of the parties hereto and their respective permitted
successors and assigns.

                                      -3-
<PAGE>

         3.3      Entire Agreement, Amendment. This Agreement constitutes the
entire agreement between the Company and Stockholder with respect to the
transactions contemplated hereby and thereby; supersedes all prior or
contemporaneous negotiations, communications, discussions and correspondence
concerning the subject matter hereof; and may be amended or modified only with
the written consent of the Company and the Stockholder.

         3.4      Severability of Provisions. If any provision of this Agreement
shall be prohibited by or invalid under applicable law, such provision shall be
ineffective only to the extent of such prohibition or invalidity without
invalidating the remainder of such provision or any remaining provisions of this
Agreement, and the parties shall use their respective best efforts to negotiate
and enter into an amendment to this Agreement whereby such provision will be
modified in a manner that is consistent with the intended economic consequences
of the invalid provision and that, as modified, is legal and enforceable.

         3.5      Governing Law. This agreement shall be governed by and
construed in accordance with the internal laws of the State of Tennessee without
giving effect to any choice of law or conflict, provision or rule (whether of
the State of Tennessee or any other jurisdiction) that would cause the laws of
any jurisdiction other than the State of Tennessee to be applied.

         3.6      Counterparts. This Agreement may be executed in separate
counterparts, either of which, when so executed, shall be deemed to be an
original and both of which, when taken together, shall constitute but one and
the same agreement.

         3.7      Survival. The representations, warranties, covenants and
agreements made herein shall survive the execution and delivery of this
Agreement and the consummation of the transactions contemplated hereby,
notwithstanding any investigation made by either party.

         3.8      Further Assurances. Each party shall at any time and from time
to time after the date hereof take whatever actions the other party or its
affiliates or agents reasonably request to effectuate, record, evidence or
perfect its transfer of the Shares to the Company pursuant to this Agreement or
to otherwise effectuate or consummate any of the transactions contemplated
hereby.

                                      -4-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed the day and year first written above.

                                     CTI, INC.

                                     By:      /s/ Terry D. Douglass
                                        ----------------------------------
                                          Terry D. Douglass
                                          President

                                     SEIKO INSTRUMENTS, INC.

                                     By:      /s/ Akio Irie
                                        ----------------------------------
                                          Akio Irie
                                          President & COO

                                      -5-

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