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Court of Appeal, Fourth District, Division 2, California.

The PEOPLE, Plaintiff and Respondent, v. Paul Seong Chul YUM, Defendant and Appellant.

No. E031437.

Decided: August 22, 2003

Russell S. Babcock, San Diego, under appointment by the Court of Appeal, for Defendant and Appellant. Bill Lockyer, Attorney General, Robert R. Anderson, Chief Assistant Attorney General, Gary W. Schons, Senior Assistant Attorney General, Robert M. Foster and Steven T. Oetting, Supervising Deputy Attorneys General, for Plaintiff and Respondent.


1. Introduction

At age 14, defendant killed his mother and his nine-year-old sister by shooting each of them in the head with a rifle.   Then, carrying about $10,000, he drove his mother's Mercedes Benz to Las Vegas and checked into the Riviera Hotel, where he was eventually apprehended by the FBI. The defense presented evidence that defendant had been abused by his father and suffered from post-traumatic stress disorder (PTSD), rendering him insane at the time of the killings.

Defendant was tried as an adult.   A jury convicted him of two counts of second degree murder.   The jury also found he was sane at the time of the murders.   Defendant is serving two concurrent sentences of 40 years to life.

Defendant contends the court erred by not giving instructions on involuntary manslaughter and not giving special instructions about defendant's mental disorders.   Defendant also asserts the court erred by not permitting evidence of defendant's SPECT 1 brain scan.

In the unpublished portion of our opinion, we hold a theory of involuntary manslaughter does not apply in this case and, also, the involuntary manslaughter and special defense instructions were properly refused.   In the published portion we hold, the SPECT brain scan is not admissible to show defendant suffered from PTSD. We affirm the judgment.


4. SPECT Brain Scan

Dr. Daniel G. Amen,9 of the Amen Clinic for Behavioral Medicine, performed a SPECT brain scan on defendant.  “Brain SPECT imaging” is described on Dr. Amen's website as “a nuclear medicine study that uses very small doses of radioisotopes to evaluate brain blood flow and activity patterns.   SPECT is widely recognized as an effective tool for evaluating brain function in strokes, seizures, dementia and head trauma․ During the past 11 years our clinics have developed this technology further to evaluate and subtype ADD, anxiety and depression, aggression, the effects of substance abuse, and non-responsive neuropsychiatric conditions.” 10

At the Evidence Code section 402 hearing on the prosecution's motion to exclude the brain scan and Dr. Amen's testimony, Dr. Amen testified that defendant's brain scan showed results associated with trauma and consistent with the SPECT pattern found in other PTSD sufferers.   He also testified that SPECT is typically used to diagnose brain trauma, strokes, seizures, and dementia but not psychiatric disorders.

In support of its motion, the prosecution presented articles from medical journals indicating brain imaging has been deemed scientifically acceptable to diagnose stroke, epilepsy, brain tumors, dementia, and Alzheimer's disease, and movement disorders, like Parkinson's disease.   The same articles also question the use of SPECT to diagnose psychiatric disorders.   The prosecution's expert witness, Dr. Peter Conti, testified there are three approved clinical uses for SPECT:  the diagnosis of stroke, epilepsy or seizure, and dementia.   Other applications are experimental and the use of SPECT to diagnose brain trauma and PTSD is controversial.   In this particular case, Dr. Conti disagreed that defendant's SPECT scans showed abnormalities.

The court ruled the defense had not shown SPECT has achieved general scientific acceptance and therefore the SPECT evidence was not admissible.

 Where expert testimony is based on the application of a new scientific technique, its proponent must demonstrate that the method employed is reliable-that is, the particular technique or test must have gained general acceptance in the field to which it belongs.11  The trial court's ruling on this issue is subject to independent review by the appellate court.12

Defendant contends that the proffered testimony of Dr. Amen was not subject at all to Kelly because it was expert medical opinion and thus fell outside the realm of evidence considered a “new scientific technique.”   This contention is belied by the record.

 As demonstrated in the evidentiary hearing, the proffered evidence was that of Dr. Amen describing brain SPECT imaging and his methods pertaining thereto, and opining that the scan revealed diminished activity in defendant's left temporal lobe, and hyperactivity elsewhere, findings consistent with brain trauma and correlated with violence, anger, and aggression.   Clearly, the purpose of Dr. Amen's testimony was to put forth evidence of defendant's SPECT scan in an attempt to show he had temporal lobe damage caused by brain trauma, which in turn caused him to kill his mother and sister.   Accordingly, in order for Dr. Amen's testimony to be admissible, defendant had to demonstrate that the use of SPECT scan imaging to diagnose brain trauma and PTSD was generally accepted in the field of brain imaging and neurology.13  Defendant failed to make this showing.

In order to establish general acceptance of the use of SPECT scans to diagnose brain trauma and PTSD, defendant had to show substantial agreement among a cross-section of the relevant scientific community.14  Defendant had to demonstrate a consensus in the field, which Dr. Amen's testimony did not.   Our review of the testimony of Doctors Amen and Conti and the pertinent medical literature reveals that the majority of qualified members in the neurology and brain imaging community does not support the use of SPECT scans to diagnose prior head trauma and mental disorders like PTSD and considers the technique generally unreliable for this purpose.   Accordingly, we hold the trial court properly excluded Dr. Amen's testimony.

5. Disposition

We affirm the judgment.


1.   Single Photon Emission Computed Tomography.

FOOTNOTE.   See footnote *, ante.

9.   Dr. Amen's internet website is


11.   People v. Kelly (1976) 17 Cal.3d 24, 30, 130 Cal.Rptr. 144, 549 P.2d 1240;  People v. Leahy (1994) 8 Cal.4th 587, 611-612, 34 Cal.Rptr.2d 663, 882 P.2d 321.

12.   People v. Ashmus (1991) 54 Cal.3d 932, 971, 2 Cal.Rptr.2d 112, 820 P.2d 214.

13.   People v. Leahy, supra, 8 Cal.4th at pages 607, 611, 34 Cal.Rptr.2d 663, 882 P.2d 321.

14.   People v. Leahy, supra, 8 Cal.4th at pages 607, 611, 34 Cal.Rptr.2d 663, 882 P.2d 321.


We concur:  RAMIREZ, P.J., and HOLLENHORST, J.

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