SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* XMARK ASSET MANAGEMENT LLC (Last) (First) (Middle) 152 W 57TH STREET, 21ST FLOOR (Street) NEW YORK NY 10019 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol IMCOR PHARMACEUTICAL CO [ ICPHC ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 04/20/2004
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, par value $0.001 per share(4)	04/20/2004		S		11,300	D	$0.9174	2,133,728	I	See footnote 1(1)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Put (right to sell)(4)	$1	04/20/2004		P			11,300(2)(3)	(2)(3)	06/18/2005	Common Stock	11,300	(2)(3)	1,611,989	I	See footnote 1(1)

Explanation of Responses:

1. On April 20, 2004, Xmark Fund, L.P., a Delaware limited partnership ("Xmark LP"), and Xmark Fund, Ltd., a Cayman Islands corporation ("Xmark Ltd."), respectively, sold 3,373 and 7,927 shares (collectively, the "April 20 Shares") of Common Stock, par value $0.001 per share (the "Common Stock"), of IMCOR Pharmaceutical Co., a Nevada corporation formerly known as Photogen Technologies, Inc. (the "Company"). The reporting person is Xmark Asset Management, LLC ("XAM"), a New York limited liability company, which is the investment manager for each of Xmark LP and Xmark Ltd. In such capacity, XAM possesses the power to vote and direct the disposition of all securities held by Xmark LP and Xmark Ltd. XAM is also the investment manager for Brown Simpson Partners I Ltd. ("BSP"). BSP owns 521,739 shares of Common Stock.

2. In consideration for Xmark LP and Xmark Ltd. each agreeing to extend the period during which it would refrain from exercising its rights and remedies as a secured creditor of Alliance Pharmaceutical Corp. ("Alliance"), the Company granted to each of Xmark LP and Xmark Ltd. the right to put to the Company, at a purchase price of $1.00 per share, all shares of Common Stock acquired by it pursuant to (i) that certain Standstill and Make Whole Agreement, dated as of December 30, 2002, by and among the Company, Xmark LP, Xmark Ltd., and Alliance and (ii) that certain Going Forward Agreement, dated as of May 2, 2003 and amended on August 18, 2003 and on March 25, 2004, by and among the Company, Xmark LP and Xmark Ltd (the "Going Forward Agreement").

3. Each of Xmark LP and Xmark Ltd. presently has the right to require the Company to purchase the shares of Common Stock currently owned by it at a per share purchase price of $1.00 on the terms and conditions set forth in the Going Forward Agreement. As a result of the disposition of the April 15 Shares, the aggregate number of shares of Common Stock that Xmark LP and Xmark Ltd., collectively, have the right to require the Company to purchase has been reduced from 1,623,289 shares to 1,611,989 shares.

4. XAM's interest in the securities reported herein, and in all prior filings with respect to the Company, is limited to its pecuniary interest in Xmark LP, Xmark Ltd., and BSP, if any.

	/s/ Mitchell D. Kaye, Manager of Xmark Asset Management, LLC	04/21/2004
	** Signature of Reporting Person	Date
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